1 This is diffutils.info-t, produced by makeinfo version 4.13 from
4 This manual is for GNU Diffutils (version 3.3, 23 March 2013), and
5 documents the GNU `diff', `diff3', `sdiff', and `cmp' commands for
6 showing the differences between files and the GNU `patch' command for
7 using their output to update files.
9 Copyright (C) 1992-1994, 1998, 2001-2002, 2004, 2006, 2009-2013 Free
10 Software Foundation, Inc.
12 Permission is granted to copy, distribute and/or modify this
13 document under the terms of the GNU Free Documentation License,
14 Version 1.3 or any later version published by the Free Software
15 Foundation; with no Invariant Sections, no Front-Cover Texts, and
16 no Back-Cover Texts. A copy of the license is included in the
17 section entitled "GNU Free Documentation License."
19 INFO-DIR-SECTION Individual utilities
21 * cmp: (diffutils)Invoking cmp. Compare 2 files byte by byte.
22 * diff: (diffutils)Invoking diff. Compare 2 files line by line.
23 * diff3: (diffutils)Invoking diff3. Compare 3 files line by line.
24 * patch: (diffutils)Invoking patch. Apply a patch to a file.
25 * sdiff: (diffutils)Invoking sdiff. Merge 2 files side-by-side.
28 INFO-DIR-SECTION Text creation and manipulation
30 * Diffutils: (diffutils). Comparing and merging files.
34 File: diffutils.info-t, Node: Top, Next: Overview, Up: (dir)
36 Comparing and Merging Files
37 ***************************
39 This manual is for GNU Diffutils (version 3.3, 23 March 2013), and
40 documents the GNU `diff', `diff3', `sdiff', and `cmp' commands for
41 showing the differences between files and the GNU `patch' command for
42 using their output to update files.
44 Copyright (C) 1992-1994, 1998, 2001-2002, 2004, 2006, 2009-2013 Free
45 Software Foundation, Inc.
47 Permission is granted to copy, distribute and/or modify this
48 document under the terms of the GNU Free Documentation License,
49 Version 1.3 or any later version published by the Free Software
50 Foundation; with no Invariant Sections, no Front-Cover Texts, and
51 no Back-Cover Texts. A copy of the license is included in the
52 section entitled "GNU Free Documentation License."
56 * Overview:: Preliminary information.
57 * Comparison:: What file comparison means.
59 * Output Formats:: Formats for two-way difference reports.
60 * Incomplete Lines:: Lines that lack trailing newlines.
61 * Comparing Directories:: Comparing files and directories.
62 * Adjusting Output:: Making `diff' output prettier.
63 * diff Performance:: Making `diff' smarter or faster.
65 * Comparing Three Files:: Formats for three-way difference reports.
66 * diff3 Merging:: Merging from a common ancestor.
68 * Interactive Merging:: Interactive merging with `sdiff'.
70 * Merging with patch:: Using `patch' to change old files into new ones.
71 * Making Patches:: Tips for making and using patch distributions.
73 * Invoking cmp:: Compare two files byte by byte.
74 * Invoking diff:: Compare two files line by line.
75 * Invoking diff3:: Compare three files line by line.
76 * Invoking patch:: Apply a diff file to an original.
77 * Invoking sdiff:: Side-by-side merge of file differences.
79 * Standards conformance:: Conformance to the POSIX standard.
80 * Projects:: If you've found a bug or other shortcoming.
82 * Copying This Manual:: How to make copies of this manual.
83 * Translations:: Available translations of this manual.
87 File: diffutils.info-t, Node: Overview, Next: Comparison, Prev: Top, Up: Top
92 Computer users often find occasion to ask how two files differ. Perhaps
93 one file is a newer version of the other file. Or maybe the two files
94 started out as identical copies but were changed by different people.
96 You can use the `diff' command to show differences between two
97 files, or each corresponding file in two directories. `diff' outputs
98 differences between files line by line in any of several formats,
99 selectable by command line options. This set of differences is often
100 called a "diff" or "patch". For files that are identical, `diff'
101 normally produces no output; for binary (non-text) files, `diff'
102 normally reports only that they are different.
104 You can use the `cmp' command to show the byte and line numbers
105 where two files differ. `cmp' can also show all the bytes that differ
106 between the two files, side by side. A way to compare two files
107 character by character is the Emacs command `M-x compare-windows'.
108 *Note Other Window: (emacs)Other Window, for more information on that
111 You can use the `diff3' command to show differences among three
112 files. When two people have made independent changes to a common
113 original, `diff3' can report the differences between the original and
114 the two changed versions, and can produce a merged file that contains
115 both persons' changes together with warnings about conflicts.
117 You can use the `sdiff' command to merge two files interactively.
119 You can use the set of differences produced by `diff' to distribute
120 updates to text files (such as program source code) to other people.
121 This method is especially useful when the differences are small compared
122 to the complete files. Given `diff' output, you can use the `patch'
123 program to update, or "patch", a copy of the file. If you think of
124 `diff' as subtracting one file from another to produce their
125 difference, you can think of `patch' as adding the difference to one
126 file to reproduce the other.
128 This manual first concentrates on making diffs, and later shows how
129 to use diffs to update files.
131 GNU `diff' was written by Paul Eggert, Mike Haertel, David Hayes,
132 Richard Stallman, and Len Tower. Wayne Davison designed and
133 implemented the unified output format. The basic algorithm is described
134 by Eugene W. Myers in "An O(ND) Difference Algorithm and its
135 Variations", `Algorithmica' Vol. 1 No. 2, 1986, pp. 251-266; and in "A
136 File Comparison Program", Webb Miller and Eugene W. Myers,
137 `Software--Practice and Experience' Vol. 15 No. 11, 1985, pp. 1025-1040.
138 The algorithm was independently discovered as described by E. Ukkonen in
139 "Algorithms for Approximate String Matching", `Information and Control'
140 Vol. 64, 1985, pp. 100-118. Unless the `--minimal' option is used,
141 `diff' uses a heuristic by Paul Eggert that limits the cost to O(N^1.5
142 log N) at the price of producing suboptimal output for large inputs
143 with many differences. Related algorithms are surveyed by Alfred V.
144 Aho in section 6.3 of "Algorithms for Finding Patterns in Strings",
145 `Handbook of Theoretical Computer Science' (Jan Van Leeuwen, ed.), Vol.
146 A, `Algorithms and Complexity', Elsevier/MIT Press, 1990, pp. 255-300.
148 GNU `diff3' was written by Randy Smith. GNU `sdiff' was written by
149 Thomas Lord. GNU `cmp' was written by Torbjo"rn Granlund and David
152 GNU `patch' was written mainly by Larry Wall and Paul Eggert;
153 several GNU enhancements were contributed by Wayne Davison and David
154 MacKenzie. Parts of this manual are adapted from a manual page written
155 by Larry Wall, with his permission.
158 File: diffutils.info-t, Node: Comparison, Next: Output Formats, Prev: Overview, Up: Top
160 1 What Comparison Means
161 ***********************
163 There are several ways to think about the differences between two files.
164 One way to think of the differences is as a series of lines that were
165 deleted from, inserted in, or changed in one file to produce the other
166 file. `diff' compares two files line by line, finds groups of lines
167 that differ, and reports each group of differing lines. It can report
168 the differing lines in several formats, which have different purposes.
170 GNU `diff' can show whether files are different without detailing
171 the differences. It also provides ways to suppress certain kinds of
172 differences that are not important to you. Most commonly, such
173 differences are changes in the amount of white space between words or
174 lines. `diff' also provides ways to suppress differences in alphabetic
175 case or in lines that match a regular expression that you provide.
176 These options can accumulate; for example, you can ignore changes in
177 both white space and alphabetic case.
179 Another way to think of the differences between two files is as a
180 sequence of pairs of bytes that can be either identical or different.
181 `cmp' reports the differences between two files byte by byte, instead
182 of line by line. As a result, it is often more useful than `diff' for
183 comparing binary files. For text files, `cmp' is useful mainly when
184 you want to know only whether two files are identical, or whether one
185 file is a prefix of the other.
187 To illustrate the effect that considering changes byte by byte can
188 have compared with considering them line by line, think of what happens
189 if a single newline character is added to the beginning of a file. If
190 that file is then compared with an otherwise identical file that lacks
191 the newline at the beginning, `diff' will report that a blank line has
192 been added to the file, while `cmp' will report that almost every byte
193 of the two files differs.
195 `diff3' normally compares three input files line by line, finds
196 groups of lines that differ, and reports each group of differing lines.
197 Its output is designed to make it easy to inspect two different sets of
198 changes to the same file.
202 * Hunks:: Groups of differing lines.
203 * White Space:: Suppressing differences in white space.
204 * Blank Lines:: Suppressing differences whose lines are all blank.
205 * Specified Lines:: Suppressing differences whose lines all match a pattern.
206 * Case Folding:: Suppressing differences in alphabetic case.
207 * Brief:: Summarizing which files are different.
208 * Binary:: Comparing binary files or forcing text comparisons.
211 File: diffutils.info-t, Node: Hunks, Next: White Space, Up: Comparison
216 When comparing two files, `diff' finds sequences of lines common to
217 both files, interspersed with groups of differing lines called "hunks".
218 Comparing two identical files yields one sequence of common lines and
219 no hunks, because no lines differ. Comparing two entirely different
220 files yields no common lines and one large hunk that contains all lines
221 of both files. In general, there are many ways to match up lines
222 between two given files. `diff' tries to minimize the total hunk size
223 by finding large sequences of common lines interspersed with small
224 hunks of differing lines.
226 For example, suppose the file `F' contains the three lines `a', `b',
227 `c', and the file `G' contains the same three lines in reverse order
228 `c', `b', `a'. If `diff' finds the line `c' as common, then the command
229 `diff F G' produces this output:
238 But if `diff' notices the common line `b' instead, it produces this
250 It is also possible to find `a' as the common line. `diff' does not
251 always find an optimal matching between the files; it takes shortcuts
252 to run faster. But its output is usually close to the shortest
253 possible. You can adjust this tradeoff with the `--minimal' (`-d')
254 option (*note diff Performance::).
257 File: diffutils.info-t, Node: White Space, Next: Blank Lines, Prev: Hunks, Up: Comparison
259 1.2 Suppressing Differences in Blank and Tab Spacing
260 ====================================================
262 The `--ignore-tab-expansion' (`-E') option ignores the distinction
263 between tabs and spaces on input. A tab is considered to be equivalent
264 to the number of spaces to the next tab stop (*note Tabs::).
266 The `--ignore-trailing-space' (`-Z') option ignores white space at
269 The `--ignore-space-change' (`-b') option is stronger than `-E' and
270 `-Z' combined. It ignores white space at line end, and considers all
271 other sequences of one or more white space characters within a line to
272 be equivalent. With this option, `diff' considers the following two
273 lines to be equivalent, where `$' denotes the line end:
275 Here lyeth muche rychnesse in lytell space. -- John Heywood$
276 Here lyeth muche rychnesse in lytell space. -- John Heywood $
278 The `--ignore-all-space' (`-w') option is stronger still. It
279 ignores differences even if one line has white space where the other
280 line has none. "White space" characters include tab, vertical tab,
281 form feed, carriage return, and space; some locales may define
282 additional characters to be white space. With this option, `diff'
283 considers the following two lines to be equivalent, where `$' denotes
284 the line end and `^M' denotes a carriage return:
286 Here lyeth muche rychnesse in lytell space.-- John Heywood$
287 He relyeth much erychnes seinly tells pace. --John Heywood ^M$
289 For many other programs newline is also a white space character, but
290 `diff' is a line-oriented program and a newline character always ends a
291 line. Hence the `-w' or `--ignore-all-space' option does not ignore
292 newline-related changes; it ignores only other white space changes.
295 File: diffutils.info-t, Node: Blank Lines, Next: Specified Lines, Prev: White Space, Up: Comparison
297 1.3 Suppressing Differences Whose Lines Are All Blank
298 =====================================================
300 The `--ignore-blank-lines' (`-B') option ignores changes that consist
301 entirely of blank lines. With this option, for example, a file
303 1. A point is that which has no part.
305 2. A line is breadthless length.
306 -- Euclid, The Elements, I
307 is considered identical to a file containing
308 1. A point is that which has no part.
309 2. A line is breadthless length.
312 -- Euclid, The Elements, I
314 Normally this option affects only lines that are completely empty,
315 but if you also specify an option that ignores trailing spaces, lines
316 are also affected if they look empty but contain white space. In other
317 words, `-B' is equivalent to `-I '^$'' by default, but it is equivalent
318 to `-I '^[[:space:]]*$'' if `-b', `-w' or `-Z' is also specified.
321 File: diffutils.info-t, Node: Specified Lines, Next: Case Folding, Prev: Blank Lines, Up: Comparison
323 1.4 Suppressing Differences Whose Lines All Match a Regular Expression
324 ======================================================================
326 To ignore insertions and deletions of lines that match a `grep'-style
327 regular expression, use the `--ignore-matching-lines=REGEXP' (`-I
328 REGEXP') option. You should escape regular expressions that contain
329 shell metacharacters to prevent the shell from expanding them. For
330 example, `diff -I '^[[:digit:]]'' ignores all changes to lines
331 beginning with a digit.
333 However, `-I' only ignores the insertion or deletion of lines that
334 contain the regular expression if every changed line in the hunk--every
335 insertion and every deletion--matches the regular expression. In other
336 words, for each nonignorable change, `diff' prints the complete set of
337 changes in its vicinity, including the ignorable ones.
339 You can specify more than one regular expression for lines to ignore
340 by using more than one `-I' option. `diff' tries to match each line
341 against each regular expression.
344 File: diffutils.info-t, Node: Case Folding, Next: Brief, Prev: Specified Lines, Up: Comparison
346 1.5 Suppressing Case Differences
347 ================================
349 GNU `diff' can treat lower case letters as equivalent to their upper
350 case counterparts, so that, for example, it considers `Funky Stuff',
351 `funky STUFF', and `fUNKy stuFf' to all be the same. To request this,
352 use the `-i' or `--ignore-case' option.
355 File: diffutils.info-t, Node: Brief, Next: Binary, Prev: Case Folding, Up: Comparison
357 1.6 Summarizing Which Files Differ
358 ==================================
360 When you only want to find out whether files are different, and you
361 don't care what the differences are, you can use the summary output
362 format. In this format, instead of showing the differences between the
363 files, `diff' simply reports whether files differ. The `--brief'
364 (`-q') option selects this output format.
366 This format is especially useful when comparing the contents of two
367 directories. It is also much faster than doing the normal line by line
368 comparisons, because `diff' can stop analyzing the files as soon as it
369 knows that there are any differences.
371 You can also get a brief indication of whether two files differ by
372 using `cmp'. For files that are identical, `cmp' produces no output.
373 When the files differ, by default, `cmp' outputs the byte and line
374 number where the first difference occurs, or reports that one file is a
375 prefix of the other. You can use the `-s', `--quiet', or `--silent'
376 option to suppress that information, so that `cmp' produces no output
377 and reports whether the files differ using only its exit status (*note
380 Unlike `diff', `cmp' cannot compare directories; it can only compare
384 File: diffutils.info-t, Node: Binary, Prev: Brief, Up: Comparison
386 1.7 Binary Files and Forcing Text Comparisons
387 =============================================
389 If `diff' thinks that either of the two files it is comparing is binary
390 (a non-text file), it normally treats that pair of files much as if the
391 summary output format had been selected (*note Brief::), and reports
392 only that the binary files are different. This is because line by line
393 comparisons are usually not meaningful for binary files.
395 `diff' determines whether a file is text or binary by checking the
396 first few bytes in the file; the exact number of bytes is system
397 dependent, but it is typically several thousand. If every byte in that
398 part of the file is non-null, `diff' considers the file to be text;
399 otherwise it considers the file to be binary.
401 Sometimes you might want to force `diff' to consider files to be
402 text. For example, you might be comparing text files that contain null
403 characters; `diff' would erroneously decide that those are non-text
404 files. Or you might be comparing documents that are in a format used
405 by a word processing system that uses null characters to indicate
406 special formatting. You can force `diff' to consider all files to be
407 text files, and compare them line by line, by using the `--text' (`-a')
408 option. If the files you compare using this option do not in fact
409 contain text, they will probably contain few newline characters, and
410 the `diff' output will consist of hunks showing differences between
411 long lines of whatever characters the files contain.
413 You can also force `diff' to report only whether files differ (but
414 not how). Use the `--brief' (`-q') option for this.
416 Normally, differing binary files count as trouble because the
417 resulting `diff' output does not capture all the differences. This
418 trouble causes `diff' to exit with status 2. However, this trouble
419 cannot occur with the `--text' (`-a') option, or with the `--brief'
420 (`-q') option, as these options both cause `diff' to generate a form of
421 output that represents differences as requested.
423 In operating systems that distinguish between text and binary files,
424 `diff' normally reads and writes all data as text. Use the `--binary'
425 option to force `diff' to read and write binary data instead. This
426 option has no effect on a POSIX-compliant system like GNU or
427 traditional Unix. However, many personal computer operating systems
428 represent the end of a line with a carriage return followed by a
429 newline. On such systems, `diff' normally ignores these carriage
430 returns on input and generates them at the end of each output line, but
431 with the `--binary' option `diff' treats each carriage return as just
432 another input character, and does not generate a carriage return at the
433 end of each output line. This can be useful when dealing with non-text
434 files that are meant to be interchanged with POSIX-compliant systems.
436 The `--strip-trailing-cr' causes `diff' to treat input lines that
437 end in carriage return followed by newline as if they end in plain
438 newline. This can be useful when comparing text that is imperfectly
439 imported from many personal computer operating systems. This option
440 affects how lines are read, which in turn affects how they are compared
443 If you want to compare two files byte by byte, you can use the `cmp'
444 program with the `--verbose' (`-l') option to show the values of each
445 differing byte in the two files. With GNU `cmp', you can also use the
446 `-b' or `--print-bytes' option to show the ASCII representation of
447 those bytes. *Note Invoking cmp::, for more information.
449 If `diff3' thinks that any of the files it is comparing is binary (a
450 non-text file), it normally reports an error, because such comparisons
451 are usually not useful. `diff3' uses the same test as `diff' to decide
452 whether a file is binary. As with `diff', if the input files contain a
453 few non-text bytes but otherwise are like text files, you can force
454 `diff3' to consider all files to be text files and compare them line by
455 line by using the `-a' or `--text' option.
458 File: diffutils.info-t, Node: Output Formats, Next: Incomplete Lines, Prev: Comparison, Up: Top
460 2 `diff' Output Formats
461 ***********************
463 `diff' has several mutually exclusive options for output format. The
464 following sections describe each format, illustrating how `diff'
465 reports the differences between two sample input files.
469 * Sample diff Input:: Sample `diff' input files for examples.
470 * Context:: Showing differences with the surrounding text.
471 * Side by Side:: Showing differences in two columns.
472 * Normal:: Showing differences without surrounding text.
473 * Scripts:: Generating scripts for other programs.
474 * If-then-else:: Merging files with if-then-else.
477 File: diffutils.info-t, Node: Sample diff Input, Next: Context, Up: Output Formats
479 2.1 Two Sample Input Files
480 ==========================
482 Here are two sample files that we will use in numerous examples to
483 illustrate the output of `diff' and how various options can change it.
485 This is the file `lao':
487 The Way that can be told of is not the eternal Way;
488 The name that can be named is not the eternal name.
489 The Nameless is the origin of Heaven and Earth;
490 The Named is the mother of all things.
491 Therefore let there always be non-being,
492 so we may see their subtlety,
493 And let there always be being,
494 so we may see their outcome.
495 The two are the same,
496 But after they are produced,
497 they have different names.
499 This is the file `tzu':
501 The Nameless is the origin of Heaven and Earth;
502 The named is the mother of all things.
504 Therefore let there always be non-being,
505 so we may see their subtlety,
506 And let there always be being,
507 so we may see their outcome.
508 The two are the same,
509 But after they are produced,
510 they have different names.
511 They both may be called deep and profound.
512 Deeper and more profound,
513 The door of all subtleties!
515 In this example, the first hunk contains just the first two lines of
516 `lao', the second hunk contains the fourth line of `lao' opposing the
517 second and third lines of `tzu', and the last hunk contains just the
518 last three lines of `tzu'.
521 File: diffutils.info-t, Node: Context, Next: Side by Side, Prev: Sample diff Input, Up: Output Formats
523 2.2 Showing Differences in Their Context
524 ========================================
526 Usually, when you are looking at the differences between files, you will
527 also want to see the parts of the files near the lines that differ, to
528 help you understand exactly what has changed. These nearby parts of the
529 files are called the "context".
531 GNU `diff' provides two output formats that show context around the
532 differing lines: "context format" and "unified format". It can
533 optionally show in which function or section of the file the differing
536 If you are distributing new versions of files to other people in the
537 form of `diff' output, you should use one of the output formats that
538 show context so that they can apply the diffs even if they have made
539 small changes of their own to the files. `patch' can apply the diffs
540 in this case by searching in the files for the lines of context around
541 the differing lines; if those lines are actually a few lines away from
542 where the diff says they are, `patch' can adjust the line numbers
543 accordingly and still apply the diff correctly. *Note Imperfect::, for
544 more information on using `patch' to apply imperfect diffs.
548 * Context Format:: An output format that shows surrounding lines.
549 * Unified Format:: A more compact output format that shows context.
550 * Sections:: Showing which sections of the files differences are in.
551 * Alternate Names:: Showing alternate file names in context headers.
554 File: diffutils.info-t, Node: Context Format, Next: Unified Format, Up: Context
559 The context output format shows several lines of context around the
560 lines that differ. It is the standard format for distributing updates
563 To select this output format, use the `--context[=LINES]' (`-C
564 LINES') or `-c' option. The argument LINES that some of these options
565 take is the number of lines of context to show. If you do not specify
566 LINES, it defaults to three. For proper operation, `patch' typically
567 needs at least two lines of context.
571 * Example Context:: Sample output in context format.
572 * Less Context:: Another sample with less context.
573 * Detailed Context:: A detailed description of the context output format.
576 File: diffutils.info-t, Node: Example Context, Next: Less Context, Up: Context Format
578 2.2.1.1 An Example of Context Format
579 ....................................
581 Here is the output of `diff -c lao tzu' (*note Sample diff Input::, for
582 the complete contents of the two files). Notice that up to three lines
583 that are not different are shown around each line that is different;
584 they are the context lines. Also notice that the first two hunks have
585 run together, because their contents overlap.
587 *** lao 2002-02-21 23:30:39.942229878 -0800
588 --- tzu 2002-02-21 23:30:50.442260588 -0800
591 - The Way that can be told of is not the eternal Way;
592 - The name that can be named is not the eternal name.
593 The Nameless is the origin of Heaven and Earth;
594 ! The Named is the mother of all things.
595 Therefore let there always be non-being,
596 so we may see their subtlety,
597 And let there always be being,
599 The Nameless is the origin of Heaven and Earth;
600 ! The named is the mother of all things.
602 Therefore let there always be non-being,
603 so we may see their subtlety,
604 And let there always be being,
608 The two are the same,
609 But after they are produced,
610 they have different names.
611 + They both may be called deep and profound.
612 + Deeper and more profound,
613 + The door of all subtleties!
616 File: diffutils.info-t, Node: Less Context, Next: Detailed Context, Prev: Example Context, Up: Context Format
618 2.2.1.2 An Example of Context Format with Less Context
619 ......................................................
621 Here is the output of `diff -C 1 lao tzu' (*note Sample diff Input::,
622 for the complete contents of the two files). Notice that at most one
623 context line is reported here.
625 *** lao 2002-02-21 23:30:39.942229878 -0800
626 --- tzu 2002-02-21 23:30:50.442260588 -0800
629 - The Way that can be told of is not the eternal Way;
630 - The name that can be named is not the eternal name.
631 The Nameless is the origin of Heaven and Earth;
632 ! The Named is the mother of all things.
633 Therefore let there always be non-being,
635 The Nameless is the origin of Heaven and Earth;
636 ! The named is the mother of all things.
638 Therefore let there always be non-being,
642 they have different names.
643 + They both may be called deep and profound.
644 + Deeper and more profound,
645 + The door of all subtleties!
648 File: diffutils.info-t, Node: Detailed Context, Prev: Less Context, Up: Context Format
650 2.2.1.3 Detailed Description of Context Format
651 ..............................................
653 The context output format starts with a two-line header, which looks
656 *** FROM-FILE FROM-FILE-MODIFICATION-TIME
657 --- TO-FILE TO-FILE-MODIFICATION TIME
659 The time stamp normally looks like `2002-02-21 23:30:39.942229878
660 -0800' to indicate the date, time with fractional seconds, and time
661 zone in Internet RFC 2822 format
662 (ftp://ftp.isi.edu/in-notes/rfc2822.txt). (The fractional seconds are
663 omitted on hosts that do not support fractional time stamps.) However,
664 a traditional time stamp like `Thu Feb 21 23:30:39 2002' is used if the
665 `LC_TIME' locale category is either `C' or `POSIX'.
667 You can change the header's content with the `--label=LABEL' option;
668 see *note Alternate Names::.
670 Next come one or more hunks of differences; each hunk shows one area
671 where the files differ. Context format hunks look like this:
674 *** FROM-FILE-LINE-NUMBERS ****
677 --- TO-FILE-LINE-NUMBERS ----
681 If a hunk contains two or more lines, its line numbers look like
682 `START,END'. Otherwise only its end line number appears. An empty
683 hunk is considered to end at the line that precedes the hunk.
685 The lines of context around the lines that differ start with two
686 space characters. The lines that differ between the two files start
687 with one of the following indicator characters, followed by a space
691 A line that is part of a group of one or more lines that changed
692 between the two files. There is a corresponding group of lines
693 marked with `!' in the part of this hunk for the other file.
696 An "inserted" line in the second file that corresponds to nothing
700 A "deleted" line in the first file that corresponds to nothing in
703 If all of the changes in a hunk are insertions, the lines of
704 FROM-FILE are omitted. If all of the changes are deletions, the lines
705 of TO-FILE are omitted.
708 File: diffutils.info-t, Node: Unified Format, Next: Sections, Prev: Context Format, Up: Context
713 The unified output format is a variation on the context format that is
714 more compact because it omits redundant context lines. To select this
715 output format, use the `--unified[=LINES]' (`-U LINES'), or `-u' option.
716 The argument LINES is the number of lines of context to show. When it
717 is not given, it defaults to three.
719 At present, only GNU `diff' can produce this format and only GNU
720 `patch' can automatically apply diffs in this format. For proper
721 operation, `patch' typically needs at least three lines of context.
725 * Example Unified:: Sample output in unified format.
726 * Detailed Unified:: A detailed description of unified format.
729 File: diffutils.info-t, Node: Example Unified, Next: Detailed Unified, Up: Unified Format
731 2.2.2.1 An Example of Unified Format
732 ....................................
734 Here is the output of the command `diff -u lao tzu' (*note Sample diff
735 Input::, for the complete contents of the two files):
737 --- lao 2002-02-21 23:30:39.942229878 -0800
738 +++ tzu 2002-02-21 23:30:50.442260588 -0800
740 -The Way that can be told of is not the eternal Way;
741 -The name that can be named is not the eternal name.
742 The Nameless is the origin of Heaven and Earth;
743 -The Named is the mother of all things.
744 +The named is the mother of all things.
746 Therefore let there always be non-being,
747 so we may see their subtlety,
748 And let there always be being,
750 The two are the same,
751 But after they are produced,
752 they have different names.
753 +They both may be called deep and profound.
754 +Deeper and more profound,
755 +The door of all subtleties!
758 File: diffutils.info-t, Node: Detailed Unified, Prev: Example Unified, Up: Unified Format
760 2.2.2.2 Detailed Description of Unified Format
761 ..............................................
763 The unified output format starts with a two-line header, which looks
766 --- FROM-FILE FROM-FILE-MODIFICATION-TIME
767 +++ TO-FILE TO-FILE-MODIFICATION-TIME
769 The time stamp looks like `2002-02-21 23:30:39.942229878 -0800' to
770 indicate the date, time with fractional seconds, and time zone. The
771 fractional seconds are omitted on hosts that do not support fractional
774 You can change the header's content with the `--label=LABEL' option.
775 *Note Alternate Names::.
777 Next come one or more hunks of differences; each hunk shows one area
778 where the files differ. Unified format hunks look like this:
780 @@ FROM-FILE-LINE-NUMBERS TO-FILE-LINE-NUMBERS @@
781 LINE-FROM-EITHER-FILE
782 LINE-FROM-EITHER-FILE...
784 If a hunk contains just one line, only its start line number appears.
785 Otherwise its line numbers look like `START,COUNT'. An empty hunk is
786 considered to start at the line that follows the hunk.
788 If a hunk and its context contain two or more lines, its line
789 numbers look like `START,COUNT'. Otherwise only its end line number
790 appears. An empty hunk is considered to end at the line that precedes
793 The lines common to both files begin with a space character. The
794 lines that actually differ between the two files have one of the
795 following indicator characters in the left print column:
798 A line was added here to the first file.
801 A line was removed here from the first file.
804 File: diffutils.info-t, Node: Sections, Next: Alternate Names, Prev: Unified Format, Up: Context
806 2.2.3 Showing Which Sections Differences Are in
807 -----------------------------------------------
809 Sometimes you might want to know which part of the files each change
810 falls in. If the files are source code, this could mean which function
811 was changed. If the files are documents, it could mean which chapter
812 or appendix was changed. GNU `diff' can show this by displaying the
813 nearest section heading line that precedes the differing lines. Which
814 lines are "section headings" is determined by a regular expression.
818 * Specified Headings:: Showing headings that match regular expressions.
819 * C Function Headings:: Showing headings of C functions.
822 File: diffutils.info-t, Node: Specified Headings, Next: C Function Headings, Up: Sections
824 2.2.3.1 Showing Lines That Match Regular Expressions
825 ....................................................
827 To show in which sections differences occur for files that are not
828 source code for C or similar languages, use the
829 `--show-function-line=REGEXP' (`-F REGEXP') option. `diff' considers
830 lines that match the `grep'-style regular expression REGEXP to be the
831 beginning of a section of the file. Here are suggested regular
832 expressions for some common languages:
843 This option does not automatically select an output format; in order
844 to use it, you must select the context format (*note Context Format::)
845 or unified format (*note Unified Format::). In other output formats it
848 The `--show-function-line' (`-F') option finds the nearest unchanged
849 line that precedes each hunk of differences and matches the given
850 regular expression. Then it adds that line to the end of the line of
851 asterisks in the context format, or to the `@@' line in unified format.
852 If no matching line exists, this option leaves the output for that hunk
853 unchanged. If that line is more than 40 characters long, it outputs
854 only the first 40 characters. You can specify more than one regular
855 expression for such lines; `diff' tries to match each line against each
856 regular expression, starting with the last one given. This means that
857 you can use `-p' and `-F' together, if you wish.
860 File: diffutils.info-t, Node: C Function Headings, Prev: Specified Headings, Up: Sections
862 2.2.3.2 Showing C Function Headings
863 ...................................
865 To show in which functions differences occur for C and similar
866 languages, you can use the `--show-c-function' (`-p') option. This
867 option automatically defaults to the context output format (*note
868 Context Format::), with the default number of lines of context. You
869 can override that number with `-C LINES' elsewhere in the command line.
870 You can override both the format and the number with `-U LINES'
871 elsewhere in the command line.
873 The `--show-c-function' (`-p') option is equivalent to `-F
874 '^[[:alpha:]$_]'' if the unified format is specified, otherwise `-c -F
875 '^[[:alpha:]$_]'' (*note Specified Headings::). GNU `diff' provides
876 this option for the sake of convenience.
879 File: diffutils.info-t, Node: Alternate Names, Prev: Sections, Up: Context
881 2.2.4 Showing Alternate File Names
882 ----------------------------------
884 If you are comparing two files that have meaningless or uninformative
885 names, you might want `diff' to show alternate names in the header of
886 the context and unified output formats. To do this, use the
887 `--label=LABEL' option. The first time you give this option, its
888 argument replaces the name and date of the first file in the header;
889 the second time, its argument replaces the name and date of the second
890 file. If you give this option more than twice, `diff' reports an
891 error. The `--label' option does not affect the file names in the `pr'
892 header when the `-l' or `--paginate' option is used (*note
895 Here are the first two lines of the output from `diff -C 2
896 --label=original --label=modified lao tzu':
902 File: diffutils.info-t, Node: Side by Side, Next: Normal, Prev: Context, Up: Output Formats
904 2.3 Showing Differences Side by Side
905 ====================================
907 `diff' can produce a side by side difference listing of two files. The
908 files are listed in two columns with a gutter between them. The gutter
909 contains one of the following markers:
912 The corresponding lines are in common. That is, either the lines
913 are identical, or the difference is ignored because of one of the
914 `--ignore' options (*note White Space::).
917 The corresponding lines differ, and they are either both complete
921 The files differ and only the first file contains the line.
924 The files differ and only the second file contains the line.
927 Only the first file contains the line, but the difference is
931 Only the second file contains the line, but the difference is
935 The corresponding lines differ, and only the first line is
939 The corresponding lines differ, and only the second line is
942 Normally, an output line is incomplete if and only if the lines that
943 it contains are incomplete. *Note Incomplete Lines::. However, when an
944 output line represents two differing lines, one might be incomplete
945 while the other is not. In this case, the output line is complete, but
946 its the gutter is marked `\' if the first line is incomplete, `/' if
949 Side by side format is sometimes easiest to read, but it has
950 limitations. It generates much wider output than usual, and truncates
951 lines that are too long to fit. Also, it relies on lining up output
952 more heavily than usual, so its output looks particularly bad if you
953 use varying width fonts, nonstandard tab stops, or nonprinting
956 You can use the `sdiff' command to interactively merge side by side
957 differences. *Note Interactive Merging::, for more information on
962 * Side by Side Format:: Controlling side by side output format.
963 * Example Side by Side:: Sample side by side output.
966 File: diffutils.info-t, Node: Side by Side Format, Next: Example Side by Side, Up: Side by Side
968 2.3.1 Controlling Side by Side Format
969 -------------------------------------
971 The `--side-by-side' (`-y') option selects side by side format.
972 Because side by side output lines contain two input lines, the output
973 is wider than usual: normally 130 print columns, which can fit onto a
974 traditional printer line. You can set the width of the output with the
975 `--width=COLUMNS' (`-W COLUMNS') option. The output is split into two
976 halves of equal width, separated by a small gutter to mark differences;
977 the right half is aligned to a tab stop so that tabs line up. Input
978 lines that are too long to fit in half of an output line are truncated
981 The `--left-column' option prints only the left column of two common
982 lines. The `--suppress-common-lines' option suppresses common lines
986 File: diffutils.info-t, Node: Example Side by Side, Prev: Side by Side Format, Up: Side by Side
988 2.3.2 An Example of Side by Side Format
989 ---------------------------------------
991 Here is the output of the command `diff -y -W 72 lao tzu' (*note Sample
992 diff Input::, for the complete contents of the two files).
994 The Way that can be told of is n <
995 The name that can be named is no <
996 The Nameless is the origin of He The Nameless is the origin of He
997 The Named is the mother of all t | The named is the mother of all t
999 Therefore let there always be no Therefore let there always be no
1000 so we may see their subtlety, so we may see their subtlety,
1001 And let there always be being, And let there always be being,
1002 so we may see their outcome. so we may see their outcome.
1003 The two are the same, The two are the same,
1004 But after they are produced, But after they are produced,
1005 they have different names. they have different names.
1006 > They both may be called deep and
1007 > Deeper and more profound,
1008 > The door of all subtleties!
1011 File: diffutils.info-t, Node: Normal, Next: Scripts, Prev: Side by Side, Up: Output Formats
1013 2.4 Showing Differences Without Context
1014 =======================================
1016 The "normal" `diff' output format shows each hunk of differences
1017 without any surrounding context. Sometimes such output is the clearest
1018 way to see how lines have changed, without the clutter of nearby
1019 unchanged lines (although you can get similar results with the context
1020 or unified formats by using 0 lines of context). However, this format
1021 is no longer widely used for sending out patches; for that purpose, the
1022 context format (*note Context Format::) and the unified format (*note
1023 Unified Format::) are superior. Normal format is the default for
1024 compatibility with older versions of `diff' and the POSIX standard.
1025 Use the `--normal' option to select this output format explicitly.
1029 * Example Normal:: Sample output in the normal format.
1030 * Detailed Normal:: A detailed description of normal output format.
1033 File: diffutils.info-t, Node: Example Normal, Next: Detailed Normal, Up: Normal
1035 2.4.1 An Example of Normal Format
1036 ---------------------------------
1038 Here is the output of the command `diff lao tzu' (*note Sample diff
1039 Input::, for the complete contents of the two files). Notice that it
1040 shows only the lines that are different between the two files.
1043 < The Way that can be told of is not the eternal Way;
1044 < The name that can be named is not the eternal name.
1046 < The Named is the mother of all things.
1048 > The named is the mother of all things.
1051 > They both may be called deep and profound.
1052 > Deeper and more profound,
1053 > The door of all subtleties!
1056 File: diffutils.info-t, Node: Detailed Normal, Prev: Example Normal, Up: Normal
1058 2.4.2 Detailed Description of Normal Format
1059 -------------------------------------------
1061 The normal output format consists of one or more hunks of differences;
1062 each hunk shows one area where the files differ. Normal format hunks
1072 There are three types of change commands. Each consists of a line
1073 number or comma-separated range of lines in the first file, a single
1074 character indicating the kind of change to make, and a line number or
1075 comma-separated range of lines in the second file. All line numbers are
1076 the original line numbers in each file. The types of change commands
1080 Add the lines in range R of the second file after line L of the
1081 first file. For example, `8a12,15' means append lines 12-15 of
1082 file 2 after line 8 of file 1; or, if changing file 2 into file 1,
1083 delete lines 12-15 of file 2.
1086 Replace the lines in range F of the first file with lines in range
1087 T of the second file. This is like a combined add and delete, but
1088 more compact. For example, `5,7c8,10' means change lines 5-7 of
1089 file 1 to read as lines 8-10 of file 2; or, if changing file 2 into
1090 file 1, change lines 8-10 of file 2 to read as lines 5-7 of file 1.
1093 Delete the lines in range R from the first file; line L is where
1094 they would have appeared in the second file had they not been
1095 deleted. For example, `5,7d3' means delete lines 5-7 of file 1;
1096 or, if changing file 2 into file 1, append lines 5-7 of file 1
1097 after line 3 of file 2.
1100 File: diffutils.info-t, Node: Scripts, Next: If-then-else, Prev: Normal, Up: Output Formats
1102 2.5 Making Edit Scripts
1103 =======================
1105 Several output modes produce command scripts for editing FROM-FILE to
1110 * ed Scripts:: Using `diff' to produce commands for `ed'.
1111 * Forward ed:: Making forward `ed' scripts.
1112 * RCS:: A special `diff' output format used by RCS.
1115 File: diffutils.info-t, Node: ed Scripts, Next: Forward ed, Up: Scripts
1120 `diff' can produce commands that direct the `ed' text editor to change
1121 the first file into the second file. Long ago, this was the only
1122 output mode that was suitable for editing one file into another
1123 automatically; today, with `patch', it is almost obsolete. Use the
1124 `--ed' (`-e') option to select this output format.
1126 Like the normal format (*note Normal::), this output format does not
1127 show any context; unlike the normal format, it does not include the
1128 information necessary to apply the diff in reverse (to produce the first
1129 file if all you have is the second file and the diff).
1131 If the file `d' contains the output of `diff -e old new', then the
1132 command `(cat d && echo w) | ed - old' edits `old' to make it a copy of
1133 `new'. More generally, if `d1', `d2', ..., `dN' contain the outputs of
1134 `diff -e old new1', `diff -e new1 new2', ..., `diff -e newN-1 newN',
1135 respectively, then the command `(cat d1 d2 ... dN && echo w) | ed -
1136 old' edits `old' to make it a copy of `newN'.
1140 * Example ed:: A sample `ed' script.
1141 * Detailed ed:: A detailed description of `ed' format.
1144 File: diffutils.info-t, Node: Example ed, Next: Detailed ed, Up: ed Scripts
1146 2.5.1.1 Example `ed' Script
1147 ...........................
1149 Here is the output of `diff -e lao tzu' (*note Sample diff Input::, for
1150 the complete contents of the two files):
1153 They both may be called deep and profound.
1154 Deeper and more profound,
1155 The door of all subtleties!
1158 The named is the mother of all things.
1164 File: diffutils.info-t, Node: Detailed ed, Prev: Example ed, Up: ed Scripts
1166 2.5.1.2 Detailed Description of `ed' Format
1167 ...........................................
1169 The `ed' output format consists of one or more hunks of differences.
1170 The changes closest to the ends of the files come first so that
1171 commands that change the number of lines do not affect how `ed'
1172 interprets line numbers in succeeding commands. `ed' format hunks look
1180 Because `ed' uses a single period on a line to indicate the end of
1181 input, GNU `diff' protects lines of changes that contain a single
1182 period on a line by writing two periods instead, then writing a
1183 subsequent `ed' command to change the two periods into one. The `ed'
1184 format cannot represent an incomplete line, so if the second file ends
1185 in a changed incomplete line, `diff' reports an error and then pretends
1186 that a newline was appended.
1188 There are three types of change commands. Each consists of a line
1189 number or comma-separated range of lines in the first file and a single
1190 character indicating the kind of change to make. All line numbers are
1191 the original line numbers in the file. The types of change commands
1195 Add text from the second file after line L in the first file. For
1196 example, `8a' means to add the following lines after line 8 of file
1200 Replace the lines in range R in the first file with the following
1201 lines. Like a combined add and delete, but more compact. For
1202 example, `5,7c' means change lines 5-7 of file 1 to read as the
1206 Delete the lines in range R from the first file. For example,
1207 `5,7d' means delete lines 5-7 of file 1.
1210 File: diffutils.info-t, Node: Forward ed, Next: RCS, Prev: ed Scripts, Up: Scripts
1212 2.5.2 Forward `ed' Scripts
1213 --------------------------
1215 `diff' can produce output that is like an `ed' script, but with hunks
1216 in forward (front to back) order. The format of the commands is also
1217 changed slightly: command characters precede the lines they modify,
1218 spaces separate line numbers in ranges, and no attempt is made to
1219 disambiguate hunk lines consisting of a single period. Like `ed'
1220 format, forward `ed' format cannot represent incomplete lines.
1222 Forward `ed' format is not very useful, because neither `ed' nor
1223 `patch' can apply diffs in this format. It exists mainly for
1224 compatibility with older versions of `diff'. Use the `-f' or
1225 `--forward-ed' option to select it.
1228 File: diffutils.info-t, Node: RCS, Prev: Forward ed, Up: Scripts
1233 The RCS output format is designed specifically for use by the Revision
1234 Control System, which is a set of free programs used for organizing
1235 different versions and systems of files. Use the `--rcs' (`-n') option
1236 to select this output format. It is like the forward `ed' format
1237 (*note Forward ed::), but it can represent arbitrary changes to the
1238 contents of a file because it avoids the forward `ed' format's problems
1239 with lines consisting of a single period and with incomplete lines.
1240 Instead of ending text sections with a line consisting of a single
1241 period, each command specifies the number of lines it affects; a
1242 combination of the `a' and `d' commands are used instead of `c'. Also,
1243 if the second file ends in a changed incomplete line, then the output
1244 also ends in an incomplete line.
1246 Here is the output of `diff -n lao tzu' (*note Sample diff Input::,
1247 for the complete contents of the two files):
1252 The named is the mother of all things.
1255 They both may be called deep and profound.
1256 Deeper and more profound,
1257 The door of all subtleties!
1260 File: diffutils.info-t, Node: If-then-else, Prev: Scripts, Up: Output Formats
1262 2.6 Merging Files with If-then-else
1263 ===================================
1265 You can use `diff' to merge two files of C source code. The output of
1266 `diff' in this format contains all the lines of both files. Lines
1267 common to both files are output just once; the differing parts are
1268 separated by the C preprocessor directives `#ifdef NAME' or `#ifndef
1269 NAME', `#else', and `#endif'. When compiling the output, you select
1270 which version to use by either defining or leaving undefined the macro
1273 To merge two files, use `diff' with the `-D NAME' or `--ifdef=NAME'
1274 option. The argument NAME is the C preprocessor identifier to use in
1275 the `#ifdef' and `#ifndef' directives.
1277 For example, if you change an instance of `wait (&s)' to `waitpid
1278 (-1, &s, 0)' and then merge the old and new files with the
1279 `--ifdef=HAVE_WAITPID' option, then the affected part of your code
1280 might look like this:
1283 #ifndef HAVE_WAITPID
1284 if ((w = wait (&s)) < 0 && errno != EINTR)
1285 #else /* HAVE_WAITPID */
1286 if ((w = waitpid (-1, &s, 0)) < 0 && errno != EINTR)
1287 #endif /* HAVE_WAITPID */
1289 } while (w != child);
1291 You can specify formats for languages other than C by using line
1292 group formats and line formats, as described in the next sections.
1296 * Line Group Formats:: Formats for general if-then-else line groups.
1297 * Line Formats:: Formats for each line in a line group.
1298 * Example If-then-else:: Sample if-then-else format output.
1299 * Detailed If-then-else:: A detailed description of if-then-else format.
1302 File: diffutils.info-t, Node: Line Group Formats, Next: Line Formats, Up: If-then-else
1304 2.6.1 Line Group Formats
1305 ------------------------
1307 Line group formats let you specify formats suitable for many
1308 applications that allow if-then-else input, including programming
1309 languages and text formatting languages. A line group format specifies
1310 the output format for a contiguous group of similar lines.
1312 For example, the following command compares the TeX files `old' and
1313 `new', and outputs a merged file in which old regions are surrounded by
1314 `\begin{em}'-`\end{em}' lines, and new regions are surrounded by
1315 `\begin{bf}'-`\end{bf}' lines.
1318 --old-group-format='\begin{em}
1321 --new-group-format='\begin{bf}
1326 The following command is equivalent to the above example, but it is a
1327 little more verbose, because it spells out the default line group
1331 --old-group-format='\begin{em}
1334 --new-group-format='\begin{bf}
1337 --unchanged-group-format='%=' \
1338 --changed-group-format='\begin{em}
1345 Here is a more advanced example, which outputs a diff listing with
1346 headers containing line numbers in a "plain English" style.
1349 --unchanged-group-format='' \
1350 --old-group-format='-------- %dn line%(n=1?:s) deleted at %df:
1352 --new-group-format='-------- %dN line%(N=1?:s) added after %de:
1354 --changed-group-format='-------- %dn line%(n=1?:s) changed at %df:
1359 To specify a line group format, use `diff' with one of the options
1360 listed below. You can specify up to four line group formats, one for
1361 each kind of line group. You should quote FORMAT, because it typically
1362 contains shell metacharacters.
1364 `--old-group-format=FORMAT'
1365 These line groups are hunks containing only lines from the first
1366 file. The default old group format is the same as the changed
1367 group format if it is specified; otherwise it is a format that
1368 outputs the line group as-is.
1370 `--new-group-format=FORMAT'
1371 These line groups are hunks containing only lines from the second
1372 file. The default new group format is same as the changed group
1373 format if it is specified; otherwise it is a format that outputs
1374 the line group as-is.
1376 `--changed-group-format=FORMAT'
1377 These line groups are hunks containing lines from both files. The
1378 default changed group format is the concatenation of the old and
1381 `--unchanged-group-format=FORMAT'
1382 These line groups contain lines common to both files. The default
1383 unchanged group format is a format that outputs the line group
1386 In a line group format, ordinary characters represent themselves;
1387 conversion specifications start with `%' and have one of the following
1391 stands for the lines from the first file, including the trailing
1392 newline. Each line is formatted according to the old line format
1393 (*note Line Formats::).
1396 stands for the lines from the second file, including the trailing
1397 newline. Each line is formatted according to the new line format.
1400 stands for the lines common to both files, including the trailing
1401 newline. Each line is formatted according to the unchanged line
1408 where C is a single character, stands for C. C may not be a
1409 backslash or an apostrophe. For example, `%c':'' stands for a
1410 colon, even inside the then-part of an if-then-else format, which
1411 a colon would normally terminate.
1414 where O is a string of 1, 2, or 3 octal digits, stands for the
1415 character with octal code O. For example, `%c'\0'' stands for a
1419 where F is a `printf' conversion specification and N is one of the
1420 following letters, stands for N's value formatted with F.
1423 The line number of the line just before the group in the old
1427 The line number of the first line in the group in the old
1431 The line number of the last line in the group in the old file.
1434 The line number of the line just after the group in the old
1438 The number of lines in the group in the old file; equals L -
1442 Likewise, for lines in the new file.
1445 The `printf' conversion specification can be `%d', `%o', `%x', or
1446 `%X', specifying decimal, octal, lower case hexadecimal, or upper
1447 case hexadecimal output respectively. After the `%' the following
1448 options can appear in sequence: a series of zero or more flags; an
1449 integer specifying the minimum field width; and a period followed
1450 by an optional integer specifying the minimum number of digits.
1451 The flags are `-' for left-justification, `'' for separating the
1452 digit into groups as specified by the `LC_NUMERIC' locale category,
1453 and `0' for padding with zeros instead of spaces. For example,
1454 `%5dN' prints the number of new lines in the group in a field of
1455 width 5 characters, using the `printf' format `"%5d"'.
1458 If A equals B then T else E. A and B are each either a decimal
1459 constant or a single letter interpreted as above. This format
1460 spec is equivalent to T if A's value equals B's; otherwise it is
1463 For example, `%(N=0?no:%dN) line%(N=1?:s)' is equivalent to `no
1464 lines' if N (the number of lines in the group in the new file) is
1465 0, to `1 line' if N is 1, and to `%dN lines' otherwise.
1468 File: diffutils.info-t, Node: Line Formats, Next: Example If-then-else, Prev: Line Group Formats, Up: If-then-else
1473 Line formats control how each line taken from an input file is output
1474 as part of a line group in if-then-else format.
1476 For example, the following command outputs text with a one-character
1477 change indicator to the left of the text. The first character of output
1478 is `-' for deleted lines, `|' for added lines, and a space for
1479 unchanged lines. The formats contain newline characters where newlines
1480 are desired on output.
1483 --old-line-format='-%l
1485 --new-line-format='|%l
1487 --unchanged-line-format=' %l
1491 To specify a line format, use one of the following options. You
1492 should quote FORMAT, since it often contains shell metacharacters.
1494 `--old-line-format=FORMAT'
1495 formats lines just from the first file.
1497 `--new-line-format=FORMAT'
1498 formats lines just from the second file.
1500 `--unchanged-line-format=FORMAT'
1501 formats lines common to both files.
1503 `--line-format=FORMAT'
1504 formats all lines; in effect, it sets all three above options
1507 In a line format, ordinary characters represent themselves;
1508 conversion specifications start with `%' and have one of the following
1512 stands for the contents of the line, not counting its trailing
1513 newline (if any). This format ignores whether the line is
1514 incomplete; *Note Incomplete Lines::.
1517 stands for the contents of the line, including its trailing newline
1518 (if any). If a line is incomplete, this format preserves its
1525 where C is a single character, stands for C. C may not be a
1526 backslash or an apostrophe. For example, `%c':'' stands for a
1530 where O is a string of 1, 2, or 3 octal digits, stands for the
1531 character with octal code O. For example, `%c'\0'' stands for a
1535 where F is a `printf' conversion specification, stands for the
1536 line number formatted with F. For example, `%.5dn' prints the
1537 line number using the `printf' format `"%.5d"'. *Note Line Group
1538 Formats::, for more about printf conversion specifications.
1541 The default line format is `%l' followed by a newline character.
1543 If the input contains tab characters and it is important that they
1544 line up on output, you should ensure that `%l' or `%L' in a line format
1545 is just after a tab stop (e.g. by preceding `%l' or `%L' with a tab
1546 character), or you should use the `-t' or `--expand-tabs' option.
1548 Taken together, the line and line group formats let you specify many
1549 different formats. For example, the following command uses a format
1550 similar to normal `diff' format. You can tailor this command to get
1551 fine control over `diff' output.
1554 --old-line-format='< %l
1556 --new-line-format='> %l
1558 --old-group-format='%df%(f=l?:,%dl)d%dE
1560 --new-group-format='%dea%dF%(F=L?:,%dL)
1562 --changed-group-format='%df%(f=l?:,%dl)c%dF%(F=L?:,%dL)
1565 --unchanged-group-format='' \
1569 File: diffutils.info-t, Node: Example If-then-else, Next: Detailed If-then-else, Prev: Line Formats, Up: If-then-else
1571 2.6.3 An Example of If-then-else Format
1572 ---------------------------------------
1574 Here is the output of `diff -DTWO lao tzu' (*note Sample diff Input::,
1575 for the complete contents of the two files):
1578 The Way that can be told of is not the eternal Way;
1579 The name that can be named is not the eternal name.
1581 The Nameless is the origin of Heaven and Earth;
1583 The Named is the mother of all things.
1585 The named is the mother of all things.
1588 Therefore let there always be non-being,
1589 so we may see their subtlety,
1590 And let there always be being,
1591 so we may see their outcome.
1592 The two are the same,
1593 But after they are produced,
1594 they have different names.
1596 They both may be called deep and profound.
1597 Deeper and more profound,
1598 The door of all subtleties!
1602 File: diffutils.info-t, Node: Detailed If-then-else, Prev: Example If-then-else, Up: If-then-else
1604 2.6.4 Detailed Description of If-then-else Format
1605 -------------------------------------------------
1607 For lines common to both files, `diff' uses the unchanged line group
1608 format. For each hunk of differences in the merged output format, if
1609 the hunk contains only lines from the first file, `diff' uses the old
1610 line group format; if the hunk contains only lines from the second
1611 file, `diff' uses the new group format; otherwise, `diff' uses the
1612 changed group format.
1614 The old, new, and unchanged line formats specify the output format of
1615 lines from the first file, lines from the second file, and lines common
1616 to both files, respectively.
1618 The option `--ifdef=NAME' is equivalent to the following sequence of
1619 options using shell syntax:
1621 --old-group-format='#ifndef NAME
1622 %<#endif /* ! NAME */
1624 --new-group-format='#ifdef NAME
1627 --unchanged-group-format='%=' \
1628 --changed-group-format='#ifndef NAME
1633 You should carefully check the `diff' output for proper nesting.
1634 For example, when using the `-D NAME' or `--ifdef=NAME' option, you
1635 should check that if the differing lines contain any of the C
1636 preprocessor directives `#ifdef', `#ifndef', `#else', `#elif', or
1637 `#endif', they are nested properly and match. If they don't, you must
1638 make corrections manually. It is a good idea to carefully check the
1639 resulting code anyway to make sure that it really does what you want it
1640 to; depending on how the input files were produced, the output might
1641 contain duplicate or otherwise incorrect code.
1643 The `patch' `-D NAME' option behaves like the `diff' `-D NAME'
1644 option, except it operates on a file and a diff to produce a merged
1645 file. *Note patch Options::.
1648 File: diffutils.info-t, Node: Incomplete Lines, Next: Comparing Directories, Prev: Output Formats, Up: Top
1653 When an input file ends in a non-newline character, its last line is
1654 called an "incomplete line" because its last character is not a
1655 newline. All other lines are called "full lines" and end in a newline
1656 character. Incomplete lines do not match full lines unless differences
1657 in white space are ignored (*note White Space::).
1659 An incomplete line is normally distinguished on output from a full
1660 line by a following line that starts with `\'. However, the RCS format
1661 (*note RCS::) outputs the incomplete line as-is, without any trailing
1662 newline or following line. The side by side format normally represents
1663 incomplete lines as-is, but in some cases uses a `\' or `/' gutter
1664 marker. *Note Side by Side::. The if-then-else line format preserves
1665 a line's incompleteness with `%L', and discards the newline with `%l'.
1666 *Note Line Formats::. Finally, with the `ed' and forward `ed' output
1667 formats (*note Output Formats::) `diff' cannot represent an incomplete
1668 line, so it pretends there was a newline and reports an error.
1670 For example, suppose `F' and `G' are one-byte files that contain
1671 just `f' and `g', respectively. Then `diff F G' outputs
1675 \ No newline at end of file
1678 \ No newline at end of file
1680 (The exact message may differ in non-English locales.) `diff -n F G'
1681 outputs the following without a trailing newline:
1687 `diff -e F G' reports two errors and outputs the following:
1694 File: diffutils.info-t, Node: Comparing Directories, Next: Adjusting Output, Prev: Incomplete Lines, Up: Top
1696 4 Comparing Directories
1697 ***********************
1699 You can use `diff' to compare some or all of the files in two directory
1700 trees. When both file name arguments to `diff' are directories, it
1701 compares each file that is contained in both directories, examining
1702 file names in alphabetical order as specified by the `LC_COLLATE'
1703 locale category. Normally `diff' is silent about pairs of files that
1704 contain no differences, but if you use the `--report-identical-files'
1705 (`-s') option, it reports pairs of identical files. Normally `diff'
1706 reports subdirectories common to both directories without comparing
1707 subdirectories' files, but if you use the `-r' or `--recursive' option,
1708 it compares every corresponding pair of files in the directory trees,
1709 as many levels deep as they go.
1711 If only one file exists, `diff' normally does not show its contents;
1712 it merely reports that one file exists but the other does not. You can
1713 make `diff' act as though the missing file is empty, so that it outputs
1714 the entire contents of the file that actually exists. (It is output as
1715 either an insertion or a deletion, depending on whether the missing
1716 file is in the first or the second position.) To do this, use the
1717 `--new-file' (`-N') option. This option affects command-line arguments
1718 as well as files found via directory traversal; for example, `diff -N a
1719 b' treats `a' as empty if `a' does not exist but `b' does, and
1720 similarly `diff -N - b' treats standard input as empty if it is closed
1723 If the older directory contains large files that are not in the
1724 newer directory, you can make the patch smaller by using the
1725 `--unidirectional-new-file' option instead of `-N'. This option is
1726 like `-N' except that it inserts the contents only of files that appear
1727 in the second directory but not the first (that is, files that were
1728 added). At the top of the patch, write instructions for the user
1729 applying the patch to remove the files that were deleted before
1730 applying the patch. *Note Making Patches::, for more discussion of
1731 making patches for distribution.
1733 To ignore some files while comparing directories, use the
1734 `--exclude=PATTERN' (`-x PATTERN') option. This option ignores any
1735 files or subdirectories whose base names match the shell pattern
1736 PATTERN. Unlike in the shell, a period at the start of the base of a
1737 file name matches a wildcard at the start of a pattern. You should
1738 enclose PATTERN in quotes so that the shell does not expand it. For
1739 example, the option `-x '*.[ao]'' ignores any file whose name ends with
1742 This option accumulates if you specify it more than once. For
1743 example, using the options `-x 'RCS' -x '*,v'' ignores any file or
1744 subdirectory whose base name is `RCS' or ends with `,v'.
1746 If you need to give this option many times, you can instead put the
1747 patterns in a file, one pattern per line, and use the
1748 `--exclude-from=FILE' (`-X FILE') option. Trailing white space and
1749 empty lines are ignored in the pattern file.
1751 If you have been comparing two directories and stopped partway
1752 through, later you might want to continue where you left off. You can
1753 do this by using the `--starting-file=FILE' (`-S FILE') option. This
1754 compares only the file FILE and all alphabetically later files in the
1755 topmost directory level.
1757 If two directories differ only in that file names are lower case in
1758 one directory and upper case in the upper, `diff' normally reports many
1759 differences because it compares file names in a case sensitive way.
1760 With the `--ignore-file-name-case' option, `diff' ignores case
1761 differences in file names, so that for example the contents of the file
1762 `Tao' in one directory are compared to the contents of the file `TAO'
1763 in the other. The `--no-ignore-file-name-case' option cancels the
1764 effect of the `--ignore-file-name-case' option, reverting to the default
1767 If an `--exclude=PATTERN' (`-x PATTERN') option, or an
1768 `--exclude-from=FILE' (`-X FILE') option, is specified while the
1769 `--ignore-file-name-case' option is in effect, case is ignored when
1770 excluding file names matching the specified patterns.
1772 To avoid that `diff' follows symbolic links, use the
1773 `--no-dereference'. When this option is in use, symbolic links will be
1774 treated like a special kind of files, rather than comparing the target
1775 of each symbolic link.
1778 File: diffutils.info-t, Node: Adjusting Output, Next: diff Performance, Prev: Comparing Directories, Up: Top
1780 5 Making `diff' Output Prettier
1781 *******************************
1783 `diff' provides several ways to adjust the appearance of its output.
1784 These adjustments can be applied to any output format.
1788 * Tabs:: Preserving the alignment of tab stops.
1789 * Trailing Blanks:: Suppressing blanks before empty output lines.
1790 * Pagination:: Page numbering and time-stamping `diff' output.
1793 File: diffutils.info-t, Node: Tabs, Next: Trailing Blanks, Up: Adjusting Output
1795 5.1 Preserving Tab Stop Alignment
1796 =================================
1798 The lines of text in some of the `diff' output formats are preceded by
1799 one or two characters that indicate whether the text is inserted,
1800 deleted, or changed. The addition of those characters can cause tabs
1801 to move to the next tab stop, throwing off the alignment of columns in
1802 the line. GNU `diff' provides two ways to make tab-aligned columns
1805 The first way is to have `diff' convert all tabs into the correct
1806 number of spaces before outputting them; select this method with the
1807 `--expand-tabs' (`-t') option. To use this form of output with
1808 `patch', you must give `patch' the `-l' or `--ignore-white-space'
1809 option (*note Changed White Space::, for more information). `diff'
1810 normally assumes that tab stops are set every 8 print columns, but this
1811 can be altered by the `--tabsize=COLUMNS' option.
1813 The other method for making tabs line up correctly is to add a tab
1814 character instead of a space after the indicator character at the
1815 beginning of the line. This ensures that all following tab characters
1816 are in the same position relative to tab stops that they were in the
1817 original files, so that the output is aligned correctly. Its
1818 disadvantage is that it can make long lines too long to fit on one line
1819 of the screen or the paper. It also does not work with the unified
1820 output format, which does not have a space character after the change
1821 type indicator character. Select this method with the `-T' or
1822 `--initial-tab' option.
1825 File: diffutils.info-t, Node: Trailing Blanks, Next: Pagination, Prev: Tabs, Up: Adjusting Output
1827 5.2 Omitting trailing blanks
1828 ============================
1830 When outputting lines in normal or context format, or outputting an
1831 unchanged line in unified format, `diff' normally outputs a blank just
1832 before each line. If the line is empty, the output of `diff' therefore
1833 contains trailing blanks even though the input does not contain them.
1834 For example, when outputting an unchanged empty line in context format,
1835 `diff' normally outputs a line with two leading spaces.
1837 Some text editors and email agents routinely delete trailing blanks,
1838 so it can be a problem to deal with diff output files that contain
1839 them. You can avoid this problem with the `--suppress-blank-empty'
1840 option. It causes `diff' to omit trailing blanks at the end of output
1841 lines in normal, context, and unified format, unless the trailing
1842 blanks were already present in the input. This changes the output
1843 format slightly, so that output lines are guaranteed to never end in a
1844 blank unless an input line ends in a blank. This format is less likely
1845 to be munged by text editors or by transmission via email. It is
1846 accepted by GNU `patch' as well.
1849 File: diffutils.info-t, Node: Pagination, Prev: Trailing Blanks, Up: Adjusting Output
1851 5.3 Paginating `diff' Output
1852 ============================
1854 It can be convenient to have long output page-numbered and time-stamped.
1855 The `--paginate' (`-l') option does this by sending the `diff' output
1856 through the `pr' program. Here is what the page header might look like
1857 for `diff -lc lao tzu':
1859 2002-02-22 14:20 diff -lc lao tzu Page 1
1862 File: diffutils.info-t, Node: diff Performance, Next: Comparing Three Files, Prev: Adjusting Output, Up: Top
1864 6 `diff' Performance Tradeoffs
1865 ******************************
1867 GNU `diff' runs quite efficiently; however, in some circumstances you
1868 can cause it to run faster or produce a more compact set of changes.
1870 One way to improve `diff' performance is to use hard or symbolic
1871 links to files instead of copies. This improves performance because
1872 `diff' normally does not need to read two hard or symbolic links to the
1873 same file, since their contents must be identical. For example,
1874 suppose you copy a large directory hierarchy, make a few changes to the
1875 copy, and then often use `diff -r' to compare the original to the copy.
1876 If the original files are read-only, you can greatly improve
1877 performance by creating the copy using hard or symbolic links (e.g.,
1878 with GNU `cp -lR' or `cp -sR'). Before editing a file in the copy for
1879 the first time, you should break the link and replace it with a regular
1882 You can also affect the performance of GNU `diff' by giving it
1883 options that change the way it compares files. Performance has more
1884 than one dimension. These options improve one aspect of performance at
1885 the cost of another, or they improve performance in some cases while
1886 hurting it in others.
1888 The way that GNU `diff' determines which lines have changed always
1889 comes up with a near-minimal set of differences. Usually it is good
1890 enough for practical purposes. If the `diff' output is large, you
1891 might want `diff' to use a modified algorithm that sometimes produces a
1892 smaller set of differences. The `--minimal' (`-d') option does this;
1893 however, it can also cause `diff' to run more slowly than usual, so it
1894 is not the default behavior.
1896 When the files you are comparing are large and have small groups of
1897 changes scattered throughout them, you can use the
1898 `--speed-large-files' option to make a different modification to the
1899 algorithm that `diff' uses. If the input files have a constant small
1900 density of changes, this option speeds up the comparisons without
1901 changing the output. If not, `diff' might produce a larger set of
1902 differences; however, the output will still be correct.
1904 Normally `diff' discards the prefix and suffix that is common to
1905 both files before it attempts to find a minimal set of differences.
1906 This makes `diff' run faster, but occasionally it may produce
1907 non-minimal output. The `--horizon-lines=LINES' option prevents `diff'
1908 from discarding the last LINES lines of the prefix and the first LINES
1909 lines of the suffix. This gives `diff' further opportunities to find a
1912 Suppose a run of changed lines includes a sequence of lines at one
1913 end and there is an identical sequence of lines just outside the other
1914 end. The `diff' command is free to choose which identical sequence is
1915 included in the hunk. In this case, `diff' normally shifts the hunk's
1916 boundaries when this merges adjacent hunks, or shifts a hunk's lines
1917 towards the end of the file. Merging hunks can make the output look
1918 nicer in some cases.
1921 File: diffutils.info-t, Node: Comparing Three Files, Next: diff3 Merging, Prev: diff Performance, Up: Top
1923 7 Comparing Three Files
1924 ***********************
1926 Use the program `diff3' to compare three files and show any differences
1927 among them. (`diff3' can also merge files; see *note diff3 Merging::).
1929 The "normal" `diff3' output format shows each hunk of differences
1930 without surrounding context. Hunks are labeled depending on whether
1931 they are two-way or three-way, and lines are annotated by their
1932 location in the input files.
1934 *Note Invoking diff3::, for more information on how to run `diff3'.
1938 * Sample diff3 Input:: Sample `diff3' input for examples.
1939 * Example diff3 Normal:: Sample output in the normal format.
1940 * Detailed diff3 Normal:: A detailed description of normal output format.
1941 * diff3 Hunks:: The format of normal output format.
1944 File: diffutils.info-t, Node: Sample diff3 Input, Next: Example diff3 Normal, Up: Comparing Three Files
1946 7.1 A Third Sample Input File
1947 =============================
1949 Here is a third sample file that will be used in examples to illustrate
1950 the output of `diff3' and how various options can change it. The first
1951 two files are the same that we used for `diff' (*note Sample diff
1952 Input::). This is the third sample file, called `tao':
1954 The Way that can be told of is not the eternal Way;
1955 The name that can be named is not the eternal name.
1956 The Nameless is the origin of Heaven and Earth;
1957 The named is the mother of all things.
1959 Therefore let there always be non-being,
1960 so we may see their subtlety,
1961 And let there always be being,
1962 so we may see their result.
1963 The two are the same,
1964 But after they are produced,
1965 they have different names.
1967 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
1970 File: diffutils.info-t, Node: Example diff3 Normal, Next: Detailed diff3 Normal, Prev: Sample diff3 Input, Up: Comparing Three Files
1972 7.2 An Example of `diff3' Normal Format
1973 =======================================
1975 Here is the output of the command `diff3 lao tzu tao' (*note Sample
1976 diff3 Input::, for the complete contents of the files). Notice that it
1977 shows only the lines that are different among the three files.
1982 The Way that can be told of is not the eternal Way;
1983 The name that can be named is not the eternal name.
1987 The Named is the mother of all things.
1990 The named is the mother of all things.
1995 so we may see their outcome.
1997 so we may see their result.
2001 They both may be called deep and profound.
2002 Deeper and more profound,
2003 The door of all subtleties!
2006 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2009 File: diffutils.info-t, Node: Detailed diff3 Normal, Next: diff3 Hunks, Prev: Example diff3 Normal, Up: Comparing Three Files
2011 7.3 Detailed Description of `diff3' Normal Format
2012 =================================================
2014 Each hunk begins with a line marked `===='. Three-way hunks have plain
2015 `====' lines, and two-way hunks have `1', `2', or `3' appended to
2016 specify which of the three input files differ in that hunk. The hunks
2017 contain copies of two or three sets of input lines each preceded by one
2018 or two commands identifying where the lines came from.
2020 Normally, two spaces precede each copy of an input line to
2021 distinguish it from the commands. But with the `--initial-tab' (`-T')
2022 option, `diff3' uses a tab instead of two spaces; this lines up tabs
2023 correctly. *Note Tabs::, for more information.
2025 Commands take the following forms:
2028 This hunk appears after line L of file FILE, and contains no lines
2029 in that file. To edit this file to yield the other files, one
2030 must append hunk lines taken from the other files. For example,
2031 `1:11a' means that the hunk follows line 11 in the first file and
2032 contains no lines from that file.
2035 This hunk contains the lines in the range R of file FILE. The
2036 range R is a comma-separated pair of line numbers, or just one
2037 number if there is only one line. To edit this file to yield the
2038 other files, one must change the specified lines to be the lines
2039 taken from the other files. For example, `2:11,13c' means that
2040 the hunk contains lines 11 through 13 from the second file.
2042 If the last line in a set of input lines is incomplete (*note
2043 Incomplete Lines::), it is distinguished on output from a full line by
2044 a following line that starts with `\'.
2047 File: diffutils.info-t, Node: diff3 Hunks, Prev: Detailed diff3 Normal, Up: Comparing Three Files
2052 Groups of lines that differ in two or three of the input files are
2053 called "diff3 hunks", by analogy with `diff' hunks (*note Hunks::). If
2054 all three input files differ in a `diff3' hunk, the hunk is called a
2055 "three-way hunk"; if just two input files differ, it is a "two-way
2058 As with `diff', several solutions are possible. When comparing the
2059 files `A', `B', and `C', `diff3' normally finds `diff3' hunks by
2060 merging the two-way hunks output by the two commands `diff A B' and
2061 `diff A C'. This does not necessarily minimize the size of the output,
2062 but exceptions should be rare.
2064 For example, suppose `F' contains the three lines `a', `b', `f', `G'
2065 contains the lines `g', `b', `g', and `H' contains the lines `a', `b',
2066 `h'. `diff3 F G H' might output the following:
2082 because it found a two-way hunk containing `a' in the first and third
2083 files and `g' in the second file, then the single line `b' common to
2084 all three files, then a three-way hunk containing the last line of each
2088 File: diffutils.info-t, Node: diff3 Merging, Next: Interactive Merging, Prev: Comparing Three Files, Up: Top
2090 8 Merging From a Common Ancestor
2091 ********************************
2093 When two people have made changes to copies of the same file, `diff3'
2094 can produce a merged output that contains both sets of changes together
2095 with warnings about conflicts.
2097 One might imagine programs with names like `diff4' and `diff5' to
2098 compare more than three files simultaneously, but in practice the need
2099 rarely arises. You can use `diff3' to merge three or more sets of
2100 changes to a file by merging two change sets at a time.
2102 `diff3' can incorporate changes from two modified versions into a
2103 common preceding version. This lets you merge the sets of changes
2104 represented by the two newer files. Specify the common ancestor version
2105 as the second argument and the two newer versions as the first and third
2106 arguments, like this:
2108 diff3 MINE OLDER YOURS
2110 You can remember the order of the arguments by noting that they are in
2113 You can think of this as subtracting OLDER from YOURS and adding the
2114 result to MINE, or as merging into MINE the changes that would turn
2115 OLDER into YOURS. This merging is well-defined as long as MINE and
2116 OLDER match in the neighborhood of each such change. This fails to be
2117 true when all three input files differ or when only OLDER differs; we
2118 call this a "conflict". When all three input files differ, we call the
2119 conflict an "overlap".
2121 `diff3' gives you several ways to handle overlaps and conflicts.
2122 You can omit overlaps or conflicts, or select only overlaps, or mark
2123 conflicts with special `<<<<<<<' and `>>>>>>>' lines.
2125 `diff3' can output the merge results as an `ed' script that that can
2126 be applied to the first file to yield the merged output. However, it
2127 is usually better to have `diff3' generate the merged output directly;
2128 this bypasses some problems with `ed'.
2132 * Which Changes:: Selecting changes to incorporate.
2133 * Marking Conflicts:: Marking conflicts.
2134 * Bypassing ed:: Generating merged output directly.
2135 * Merging Incomplete Lines:: How `diff3' merges incomplete lines.
2136 * Saving the Changed File:: Emulating System V behavior.
2139 File: diffutils.info-t, Node: Which Changes, Next: Marking Conflicts, Up: diff3 Merging
2141 8.1 Selecting Which Changes to Incorporate
2142 ==========================================
2144 You can select all unmerged changes from OLDER to YOURS for merging
2145 into MINE with the `--ed' (`-e') option. You can select only the
2146 nonoverlapping unmerged changes with `--easy-only' (`-3'), and you can
2147 select only the overlapping changes with `--overlap-only' (`-x').
2149 The `-e', `-3' and `-x' options select only "unmerged changes", i.e.
2150 changes where MINE and YOURS differ; they ignore changes from OLDER to
2151 YOURS where MINE and YOURS are identical, because they assume that such
2152 changes have already been merged. If this assumption is not a safe
2153 one, you can use the `--show-all' (`-A') option (*note Marking
2156 Here is the output of the command `diff3' with each of these three
2157 options (*note Sample diff3 Input::, for the complete contents of the
2158 files). Notice that `-e' outputs the union of the disjoint sets of
2159 changes output by `-3' and `-x'.
2161 Output of `diff3 -e lao tzu tao':
2164 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2167 so we may see their result.
2170 Output of `diff3 -3 lao tzu tao':
2172 so we may see their result.
2175 Output of `diff3 -x lao tzu tao':
2178 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2182 File: diffutils.info-t, Node: Marking Conflicts, Next: Bypassing ed, Prev: Which Changes, Up: diff3 Merging
2184 8.2 Marking Conflicts
2185 =====================
2187 `diff3' can mark conflicts in the merged output by bracketing them with
2188 special marker lines. A conflict that comes from two files A and B is
2197 A conflict that comes from three files A, B and C is marked as
2208 The `--show-all' (`-A') option acts like the `-e' option, except
2209 that it brackets conflicts, and it outputs all changes from OLDER to
2210 YOURS, not just the unmerged changes. Thus, given the sample input
2211 files (*note Sample diff3 Input::), `diff3 -A lao tzu tao' puts
2212 brackets around the conflict where only `tzu' differs:
2216 The Way that can be told of is not the eternal Way;
2217 The name that can be named is not the eternal name.
2220 And it outputs the three-way conflict as follows:
2224 They both may be called deep and profound.
2225 Deeper and more profound,
2226 The door of all subtleties!
2229 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2232 The `--show-overlap' (`-E') option outputs less information than the
2233 `--show-all' (`-A') option, because it outputs only unmerged changes,
2234 and it never outputs the contents of the second file. Thus the `-E'
2235 option acts like the `-e' option, except that it brackets the first and
2236 third files from three-way overlapping changes. Similarly, `-X' acts
2237 like `-x', except it brackets all its (necessarily overlapping)
2238 changes. For example, for the three-way overlapping change above, the
2239 `-E' and `-X' options output the following:
2244 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2247 If you are comparing files that have meaningless or uninformative
2248 names, you can use the `--label=LABEL' option to show alternate names
2249 in the `<<<<<<<', `|||||||' and `>>>>>>>' brackets. This option can be
2250 given up to three times, once for each input file. Thus `diff3 -A
2251 --label X --label Y --label Z A B C' acts like `diff3 -A A B C', except
2252 that the output looks like it came from files named `X', `Y' and `Z'
2253 rather than from files named `A', `B' and `C'.
2256 File: diffutils.info-t, Node: Bypassing ed, Next: Merging Incomplete Lines, Prev: Marking Conflicts, Up: diff3 Merging
2258 8.3 Generating the Merged Output Directly
2259 =========================================
2261 With the `--merge' (`-m') option, `diff3' outputs the merged file
2262 directly. This is more efficient than using `ed' to generate it, and
2263 works even with non-text files that `ed' would reject. If you specify
2264 `-m' without an `ed' script option, `-A' is assumed.
2266 For example, the command `diff3 -m lao tzu tao' (*note Sample diff3
2267 Input:: for a copy of the input files) would output the following:
2271 The Way that can be told of is not the eternal Way;
2272 The name that can be named is not the eternal name.
2274 The Nameless is the origin of Heaven and Earth;
2275 The Named is the mother of all things.
2276 Therefore let there always be non-being,
2277 so we may see their subtlety,
2278 And let there always be being,
2279 so we may see their result.
2280 The two are the same,
2281 But after they are produced,
2282 they have different names.
2285 They both may be called deep and profound.
2286 Deeper and more profound,
2287 The door of all subtleties!
2290 -- The Way of Lao-Tzu, tr. Wing-tsit Chan
2294 File: diffutils.info-t, Node: Merging Incomplete Lines, Next: Saving the Changed File, Prev: Bypassing ed, Up: diff3 Merging
2296 8.4 How `diff3' Merges Incomplete Lines
2297 =======================================
2299 With `-m', incomplete lines (*note Incomplete Lines::) are simply
2300 copied to the output as they are found; if the merged output ends in an
2301 conflict and one of the input files ends in an incomplete line,
2302 succeeding `|||||||', `=======' or `>>>>>>>' brackets appear somewhere
2303 other than the start of a line because they are appended to the
2306 Without `-m', if an `ed' script option is specified and an
2307 incomplete line is found, `diff3' generates a warning and acts as if a
2308 newline had been present.
2311 File: diffutils.info-t, Node: Saving the Changed File, Prev: Merging Incomplete Lines, Up: diff3 Merging
2313 8.5 Saving the Changed File
2314 ===========================
2316 Traditional Unix `diff3' generates an `ed' script without the trailing
2317 `w' and `q' commands that save the changes. System V `diff3' generates
2318 these extra commands. GNU `diff3' normally behaves like traditional
2319 Unix `diff3', but with the `-i' option it behaves like System V `diff3'
2320 and appends the `w' and `q' commands.
2322 The `-i' option requires one of the `ed' script options `-AeExX3',
2323 and is incompatible with the merged output option `-m'.
2326 File: diffutils.info-t, Node: Interactive Merging, Next: Merging with patch, Prev: diff3 Merging, Up: Top
2328 9 Interactive Merging with `sdiff'
2329 **********************************
2331 With `sdiff', you can merge two files interactively based on a
2332 side-by-side `-y' format comparison (*note Side by Side::). Use
2333 `--output=FILE' (`-o FILE') to specify where to put the merged text.
2334 *Note Invoking sdiff::, for more details on the options to `sdiff'.
2336 Another way to merge files interactively is to use the Emacs Lisp
2337 package `emerge'. *Note emerge: (emacs)emerge, for more information.
2341 * sdiff Option Summary:: Summary of `sdiff' options.
2342 * Merge Commands:: Merging two files interactively.
2345 File: diffutils.info-t, Node: sdiff Option Summary, Next: Merge Commands, Up: Interactive Merging
2347 9.1 Specifying `diff' Options to `sdiff'
2348 ========================================
2350 The following `sdiff' options have the same meaning as for `diff'.
2351 *Note diff Options::, for the use of these options.
2357 --ignore-blank-lines --ignore-case
2358 --ignore-matching-lines=REGEXP --ignore-space-change
2359 --ignore-tab-expansion --ignore-trailing-space
2360 --left-column --minimal --speed-large-files
2361 --strip-trailing-cr --suppress-common-lines
2362 --tabsize=COLUMNS --text --version --width=COLUMNS
2364 For historical reasons, `sdiff' has alternate names for some
2365 options. The `-l' option is equivalent to the `--left-column' option,
2366 and similarly `-s' is equivalent to `--suppress-common-lines'. The
2367 meaning of the `sdiff' `-w' and `-W' options is interchanged from that
2368 of `diff': with `sdiff', `-w COLUMNS' is equivalent to
2369 `--width=COLUMNS', and `-W' is equivalent to `--ignore-all-space'.
2370 `sdiff' without the `-o' option is equivalent to `diff' with the
2371 `--side-by-side' (`-y') option (*note Side by Side::).
2374 File: diffutils.info-t, Node: Merge Commands, Prev: sdiff Option Summary, Up: Interactive Merging
2379 Groups of common lines, with a blank gutter, are copied from the first
2380 file to the output. After each group of differing lines, `sdiff'
2381 prompts with `%' and pauses, waiting for one of the following commands.
2382 Follow each command with <RET>.
2385 Discard both versions. Invoke a text editor on an empty temporary
2386 file, then copy the resulting file to the output.
2389 Concatenate the two versions, edit the result in a temporary file,
2390 then copy the edited result to the output.
2393 Like `eb', except precede each version with a header that shows
2394 what file and lines the version came from.
2398 Edit a copy of the left version, then copy the result to the
2403 Edit a copy of the right version, then copy the result to the
2408 Copy the left version to the output.
2415 Copy the right version to the output.
2418 Silently copy common lines.
2421 Verbosely copy common lines. This is the default.
2423 The text editor invoked is specified by the `EDITOR' environment
2424 variable if it is set. The default is system-dependent.
2427 File: diffutils.info-t, Node: Merging with patch, Next: Making Patches, Prev: Interactive Merging, Up: Top
2429 10 Merging with `patch'
2430 ***********************
2432 `patch' takes comparison output produced by `diff' and applies the
2433 differences to a copy of the original file, producing a patched
2434 version. With `patch', you can distribute just the changes to a set of
2435 files instead of distributing the entire file set; your correspondents
2436 can apply `patch' to update their copy of the files with your changes.
2437 `patch' automatically determines the diff format, skips any leading or
2438 trailing headers, and uses the headers to determine which file to
2439 patch. This lets your correspondents feed a mail message containing a
2440 difference listing directly to `patch'.
2442 `patch' detects and warns about common problems like forward
2443 patches. It saves any patches that it could not apply. It can also
2444 maintain a `patchlevel.h' file to ensure that your correspondents apply
2445 diffs in the proper order.
2447 `patch' accepts a series of diffs in its standard input, usually
2448 separated by headers that specify which file to patch. It applies
2449 `diff' hunks (*note Hunks::) one by one. If a hunk does not exactly
2450 match the original file, `patch' uses heuristics to try to patch the
2451 file as well as it can. If no approximate match can be found, `patch'
2452 rejects the hunk and skips to the next hunk. `patch' normally replaces
2453 each file F with its new version, putting reject hunks (if any) into
2456 *Note Invoking patch::, for detailed information on the options to
2461 * patch Input:: Selecting the type of `patch' input.
2462 * Revision Control:: Getting files from RCS, SCCS, etc.
2463 * Imperfect:: Dealing with imperfect patches.
2464 * Creating and Removing:: Creating and removing files with a patch.
2465 * Patching Time Stamps:: Updating time stamps on patched files.
2466 * Multiple Patches:: Handling multiple patches in a file.
2467 * patch Directories:: Changing directory and stripping directories.
2468 * Backups:: Whether backup files are made.
2469 * Backup Names:: Backup file names.
2470 * Reject Names:: Reject file names.
2471 * patch Messages:: Messages and questions `patch' can produce.
2472 * patch and POSIX:: Conformance to the POSIX standard.
2473 * patch and Tradition:: GNU versus traditional `patch'.
2476 File: diffutils.info-t, Node: patch Input, Next: Revision Control, Up: Merging with patch
2478 10.1 Selecting the `patch' Input Format
2479 =======================================
2481 `patch' normally determines which `diff' format the patch file uses by
2482 examining its contents. For patch files that contain particularly
2483 confusing leading text, you might need to use one of the following
2484 options to force `patch' to interpret the patch file as a certain
2485 format of diff. The output formats listed here are the only ones that
2486 `patch' can understand.
2505 File: diffutils.info-t, Node: Revision Control, Next: Imperfect, Prev: patch Input, Up: Merging with patch
2507 10.2 Revision Control
2508 =====================
2510 If a nonexistent input file is under a revision control system
2511 supported by `patch', `patch' normally asks the user whether to get (or
2512 check out) the file from the revision control system. Patch currently
2513 supports RCS, ClearCase and SCCS. Under RCS and SCCS, `patch' also
2514 asks when the input file is read-only and matches the default version
2515 in the revision control system.
2517 The `--get=NUM' (`-g NUM') option affects access to files under
2518 supported revision control systems. If NUM is positive, `patch' gets
2519 the file without asking the user; if zero, `patch' neither asks the
2520 user nor gets the file; and if negative, `patch' asks the user before
2521 getting the file. The default value of NUM is given by the value of the
2522 `PATCH_GET' environment variable if it is set; if not, the default
2523 value is zero if `patch' is conforming to POSIX, negative otherwise.
2524 *Note patch and POSIX::.
2526 The choice of revision control system is unaffected by the
2527 `VERSION_CONTROL' environment variable (*note Backup Names::).
2530 File: diffutils.info-t, Node: Imperfect, Next: Creating and Removing, Prev: Revision Control, Up: Merging with patch
2532 10.3 Applying Imperfect Patches
2533 ===============================
2535 `patch' tries to skip any leading text in the patch file, apply the
2536 diff, and then skip any trailing text. Thus you can feed a mail
2537 message directly to `patch', and it should work. If the entire diff is
2538 indented by a constant amount of white space, `patch' automatically
2539 ignores the indentation. If a context diff contains trailing carriage
2540 return on each line, `patch' automatically ignores the carriage return.
2541 If a context diff has been encapsulated by prepending `- ' to lines
2542 beginning with `-' as per Internet RFC 934
2543 (ftp://ftp.isi.edu/in-notes/rfc934.txt), `patch' automatically
2544 unencapsulates the input.
2546 However, certain other types of imperfect input require user
2547 intervention or testing.
2551 * Changed White Space:: When tabs and spaces don't match exactly.
2552 * Reversed Patches:: Applying reversed patches correctly.
2553 * Inexact:: Helping `patch' find close matches.
2554 * Dry Runs:: Predicting what `patch' will do.
2557 File: diffutils.info-t, Node: Changed White Space, Next: Reversed Patches, Up: Imperfect
2559 10.3.1 Applying Patches with Changed White Space
2560 ------------------------------------------------
2562 Sometimes mailers, editors, or other programs change spaces into tabs,
2563 or vice versa. If this happens to a patch file or an input file, the
2564 files might look the same, but `patch' will not be able to match them
2565 properly. If this problem occurs, use the `-l' or
2566 `--ignore-white-space' option, which makes `patch' compare blank
2567 characters (i.e. spaces and tabs) loosely so that any nonempty sequence
2568 of blanks in the patch file matches any nonempty sequence of blanks in
2569 the input files. Non-blank characters must still match exactly. Each
2570 line of the context must still match a line in the input file.
2573 File: diffutils.info-t, Node: Reversed Patches, Next: Inexact, Prev: Changed White Space, Up: Imperfect
2575 10.3.2 Applying Reversed Patches
2576 --------------------------------
2578 Sometimes people run `diff' with the new file first instead of second.
2579 This creates a diff that is "reversed". To apply such patches, give
2580 `patch' the `--reverse' (`-R') option. `patch' then attempts to swap
2581 each hunk around before applying it. Rejects come out in the swapped
2584 Often `patch' can guess that the patch is reversed. If the first
2585 hunk of a patch fails, `patch' reverses the hunk to see if it can apply
2586 it that way. If it can, `patch' asks you if you want to have the `-R'
2587 option set; if it can't, `patch' continues to apply the patch normally.
2588 This method cannot detect a reversed patch if it is a normal diff and
2589 the first command is an append (which should have been a delete) since
2590 appends always succeed, because a null context matches anywhere. But
2591 most patches add or change lines rather than delete them, so most
2592 reversed normal diffs begin with a delete, which fails, and `patch'
2595 If you apply a patch that you have already applied, `patch' thinks
2596 it is a reversed patch and offers to un-apply the patch. This could be
2597 construed as a feature. If you did this inadvertently and you don't
2598 want to un-apply the patch, just answer `n' to this offer and to the
2599 subsequent "apply anyway" question--or type `C-c' to kill the `patch'
2603 File: diffutils.info-t, Node: Inexact, Next: Dry Runs, Prev: Reversed Patches, Up: Imperfect
2605 10.3.3 Helping `patch' Find Inexact Matches
2606 -------------------------------------------
2608 For context diffs, and to a lesser extent normal diffs, `patch' can
2609 detect when the line numbers mentioned in the patch are incorrect, and
2610 it attempts to find the correct place to apply each hunk of the patch.
2611 As a first guess, it takes the line number mentioned in the hunk, plus
2612 or minus any offset used in applying the previous hunk. If that is not
2613 the correct place, `patch' scans both forward and backward for a set of
2614 lines matching the context given in the hunk.
2616 First `patch' looks for a place where all lines of the context
2617 match. If it cannot find such a place, and it is reading a context or
2618 unified diff, and the maximum fuzz factor is set to 1 or more, then
2619 `patch' makes another scan, ignoring the first and last line of
2620 context. If that fails, and the maximum fuzz factor is set to 2 or
2621 more, it makes another scan, ignoring the first two and last two lines
2622 of context are ignored. It continues similarly if the maximum fuzz
2625 The `--fuzz=LINES' (`-F LINES') option sets the maximum fuzz factor
2626 to LINES. This option only applies to context and unified diffs; it
2627 ignores up to LINES lines while looking for the place to install a
2628 hunk. Note that a larger fuzz factor increases the odds of making a
2629 faulty patch. The default fuzz factor is 2; there is no point to
2630 setting it to more than the number of lines of context in the diff,
2633 If `patch' cannot find a place to install a hunk of the patch, it
2634 writes the hunk out to a reject file (*note Reject Names::, for
2635 information on how reject files are named). It writes out rejected
2636 hunks in context format no matter what form the input patch is in. If
2637 the input is a normal or `ed' diff, many of the contexts are simply
2638 null. The line numbers on the hunks in the reject file may be
2639 different from those in the patch file: they show the approximate
2640 location where `patch' thinks the failed hunks belong in the new file
2641 rather than in the old one.
2643 If the `--verbose' option is given, then as it completes each hunk
2644 `patch' tells you whether the hunk succeeded or failed, and if it
2645 failed, on which line (in the new file) `patch' thinks the hunk should
2646 go. If this is different from the line number specified in the diff,
2647 it tells you the offset. A single large offset _may_ indicate that
2648 `patch' installed a hunk in the wrong place. `patch' also tells you if
2649 it used a fuzz factor to make the match, in which case you should also
2650 be slightly suspicious.
2652 `patch' cannot tell if the line numbers are off in an `ed' script,
2653 and can only detect wrong line numbers in a normal diff when it finds a
2654 change or delete command. It may have the same problem with a context
2655 diff using a fuzz factor equal to or greater than the number of lines
2656 of context shown in the diff (typically 3). In these cases, you should
2657 probably look at a context diff between your original and patched input
2658 files to see if the changes make sense. Compiling without errors is a
2659 pretty good indication that the patch worked, but not a guarantee.
2661 A patch against an empty file applies to a nonexistent file, and vice
2662 versa. *Note Creating and Removing::.
2664 `patch' usually produces the correct results, even when it must make
2665 many guesses. However, the results are guaranteed only when the patch
2666 is applied to an exact copy of the file that the patch was generated
2670 File: diffutils.info-t, Node: Dry Runs, Prev: Inexact, Up: Imperfect
2672 10.3.4 Predicting what `patch' will do
2673 --------------------------------------
2675 It may not be obvious in advance what `patch' will do with a
2676 complicated or poorly formatted patch. If you are concerned that the
2677 input might cause `patch' to modify the wrong files, you can use the
2678 `--dry-run' option, which causes `patch' to print the results of
2679 applying patches without actually changing any files. You can then
2680 inspect the diagnostics generated by the dry run to see whether `patch'
2681 will modify the files that you expect. If the patch does not do what
2682 you want, you can modify the patch (or the other options to `patch')
2683 and try another dry run. Once you are satisfied with the proposed
2684 patch you can apply it by invoking `patch' as before, but this time
2685 without the `--dry-run' option.
2688 File: diffutils.info-t, Node: Creating and Removing, Next: Patching Time Stamps, Prev: Imperfect, Up: Merging with patch
2690 10.4 Creating and Removing Files
2691 ================================
2693 Sometimes when comparing two directories, a file may exist in one
2694 directory but not the other. If you give `diff' the `--new-file'
2695 (`-N') option, or if you supply an old or new file that is named
2696 `/dev/null' or is empty and is dated the Epoch (1970-01-01 00:00:00
2697 UTC), `diff' outputs a patch that adds or deletes the contents of this
2698 file. When given such a patch, `patch' normally creates a new file or
2699 removes the old file. However, when conforming to POSIX (*note patch
2700 and POSIX::), `patch' does not remove the old file, but leaves it empty.
2701 The `--remove-empty-files' (`-E') option causes `patch' to remove
2702 output files that are empty after applying a patch, even if the patch
2703 does not appear to be one that removed the file.
2705 If the patch appears to create a file that already exists, `patch'
2706 asks for confirmation before applying the patch.
2709 File: diffutils.info-t, Node: Patching Time Stamps, Next: Multiple Patches, Prev: Creating and Removing, Up: Merging with patch
2711 10.5 Updating Time Stamps on Patched Files
2712 ==========================================
2714 When `patch' updates a file, it normally sets the file's last-modified
2715 time stamp to the current time of day. If you are using `patch' to
2716 track a software distribution, this can cause `make' to incorrectly
2717 conclude that a patched file is out of date. For example, if
2718 `syntax.c' depends on `syntax.y', and `patch' updates `syntax.c' and
2719 then `syntax.y', then `syntax.c' will normally appear to be out of date
2720 with respect to `syntax.y' even though its contents are actually up to
2723 The `--set-utc' (`-Z') option causes `patch' to set a patched file's
2724 modification and access times to the time stamps given in context diff
2725 headers. If the context diff headers do not specify a time zone, they
2726 are assumed to use Coordinated Universal Time (UTC, often known as GMT).
2728 The `--set-time' (`-T') option acts like `-Z' or `--set-utc', except
2729 that it assumes that the context diff headers' time stamps use local
2730 time instead of UTC. This option is not recommended, because patches
2731 using local time cannot easily be used by people in other time zones,
2732 and because local time stamps are ambiguous when local clocks move
2733 backwards during daylight-saving time adjustments. If the context diff
2734 headers specify a time zone, this option is equivalent to `--set-utc'
2737 `patch' normally refrains from setting a file's time stamps if the
2738 file's original last-modified time stamp does not match the time given
2739 in the diff header, of if the file's contents do not exactly match the
2740 patch. However, if the `--force' (`-f') option is given, the file's
2741 time stamps are set regardless.
2743 Due to the limitations of the current `diff' format, `patch' cannot
2744 update the times of files whose contents have not changed. Also, if
2745 you set file time stamps to values other than the current time of day,
2746 you should also remove (e.g., with `make clean') all files that depend
2747 on the patched files, so that later invocations of `make' do not get
2748 confused by the patched files' times.
2751 File: diffutils.info-t, Node: Multiple Patches, Next: patch Directories, Prev: Patching Time Stamps, Up: Merging with patch
2753 10.6 Multiple Patches in a File
2754 ===============================
2756 If the patch file contains more than one patch, and if you do not
2757 specify an input file on the command line, `patch' tries to apply each
2758 patch as if they came from separate patch files. This means that it
2759 determines the name of the file to patch for each patch, and that it
2760 examines the leading text before each patch for file names and
2761 prerequisite revision level (*note Making Patches::, for more on that
2764 `patch' uses the following rules to intuit a file name from the
2765 leading text before a patch. First, `patch' takes an ordered list of
2766 candidate file names as follows:
2768 * If the header is that of a context diff, `patch' takes the old and
2769 new file names in the header. A name is ignored if it does not
2770 have enough slashes to satisfy the `-pNUM' or `--strip=NUM'
2771 option. The name `/dev/null' is also ignored.
2773 * If there is an `Index:' line in the leading garbage and if either
2774 the old and new names are both absent or if `patch' is conforming
2775 to POSIX, `patch' takes the name in the `Index:' line.
2777 * For the purpose of the following rules, the candidate file names
2778 are considered to be in the order (old, new, index), regardless of
2779 the order that they appear in the header.
2781 Then `patch' selects a file name from the candidate list as follows:
2783 * If some of the named files exist, `patch' selects the first name
2784 if conforming to POSIX, and the best name otherwise.
2786 * If `patch' is not ignoring RCS, ClearCase, and SCCS (*note
2787 Revision Control::), and no named files exist but an RCS,
2788 ClearCase, or SCCS master is found, `patch' selects the first
2789 named file with an RCS, ClearCase, or SCCS master.
2791 * If no named files exist, no RCS, ClearCase, or SCCS master was
2792 found, some names are given, `patch' is not conforming to POSIX,
2793 and the patch appears to create a file, `patch' selects the best
2794 name requiring the creation of the fewest directories.
2796 * If no file name results from the above heuristics, you are asked
2797 for the name of the file to patch, and `patch' selects that name.
2799 To determine the "best" of a nonempty list of file names, `patch'
2800 first takes all the names with the fewest path name components; of
2801 those, it then takes all the names with the shortest basename; of
2802 those, it then takes all the shortest names; finally, it takes the
2803 first remaining name.
2805 *Note patch and POSIX::, to see whether `patch' is conforming to
2809 File: diffutils.info-t, Node: patch Directories, Next: Backups, Prev: Multiple Patches, Up: Merging with patch
2811 10.7 Applying Patches in Other Directories
2812 ==========================================
2814 The `--directory=DIRECTORY' (`-d DIRECTORY') option to `patch' makes
2815 directory DIRECTORY the current directory for interpreting both file
2816 names in the patch file, and file names given as arguments to other
2817 options (such as `-B' and `-o'). For example, while in a mail reading
2818 program, you can patch a file in the `/usr/src/emacs' directory
2819 directly from a message containing the patch like this:
2821 | patch -d /usr/src/emacs
2823 Sometimes the file names given in a patch contain leading
2824 directories, but you keep your files in a directory different from the
2825 one given in the patch. In those cases, you can use the
2826 `--strip=NUMBER' (`-pNUMBER') option to set the file name strip count
2827 to NUMBER. The strip count tells `patch' how many slashes, along with
2828 the directory names between them, to strip from the front of file
2829 names. A sequence of one or more adjacent slashes is counted as a
2830 single slash. By default, `patch' strips off all leading directories,
2831 leaving just the base file names.
2833 For example, suppose the file name in the patch file is
2834 `/gnu/src/emacs/etc/NEWS'. Using `-p0' gives the entire file name
2835 unmodified, `-p1' gives `gnu/src/emacs/etc/NEWS' (no leading slash),
2836 `-p4' gives `etc/NEWS', and not specifying `-p' at all gives `NEWS'.
2838 `patch' looks for each file (after any slashes have been stripped)
2839 in the current directory, or if you used the `-d DIRECTORY' option, in
2843 File: diffutils.info-t, Node: Backups, Next: Backup Names, Prev: patch Directories, Up: Merging with patch
2848 Normally, `patch' creates a backup file if the patch does not exactly
2849 match the original input file, because in that case the original data
2850 might not be recovered if you undo the patch with `patch -R' (*note
2851 Reversed Patches::). However, when conforming to POSIX, `patch' does
2852 not create backup files by default. *Note patch and POSIX::.
2854 The `--backup' (`-b') option causes `patch' to make a backup file
2855 regardless of whether the patch matches the original input. The
2856 `--backup-if-mismatch' option causes `patch' to create backup files for
2857 mismatches files; this is the default when not conforming to POSIX. The
2858 `--no-backup-if-mismatch' option causes `patch' to not create backup
2859 files, even for mismatched patches; this is the default when conforming
2862 When backing up a file that does not exist, an empty, unreadable
2863 backup file is created as a placeholder to represent the nonexistent
2867 File: diffutils.info-t, Node: Backup Names, Next: Reject Names, Prev: Backups, Up: Merging with patch
2869 10.9 Backup File Names
2870 ======================
2872 Normally, `patch' renames an original input file into a backup file by
2873 appending to its name the extension `.orig', or `~' if using `.orig'
2874 would make the backup file name too long.(1) The `-z BACKUP-SUFFIX' or
2875 `--suffix=BACKUP-SUFFIX' option causes `patch' to use BACKUP-SUFFIX as
2876 the backup extension instead.
2878 Alternately, you can specify the extension for backup files with the
2879 `SIMPLE_BACKUP_SUFFIX' environment variable, which the options override.
2881 `patch' can also create numbered backup files the way GNU Emacs
2882 does. With this method, instead of having a single backup of each
2883 file, `patch' makes a new backup file name each time it patches a file.
2884 For example, the backups of a file named `sink' would be called,
2885 successively, `sink.~1~', `sink.~2~', `sink.~3~', etc.
2887 The `-V BACKUP-STYLE' or `--version-control=BACKUP-STYLE' option
2888 takes as an argument a method for creating backup file names. You can
2889 alternately control the type of backups that `patch' makes with the
2890 `PATCH_VERSION_CONTROL' environment variable, which the `-V' option
2891 overrides. If `PATCH_VERSION_CONTROL' is not set, the
2892 `VERSION_CONTROL' environment variable is used instead. Please note
2893 that these options and variables control backup file names; they do not
2894 affect the choice of revision control system (*note Revision Control::).
2896 The values of these environment variables and the argument to the
2897 `-V' option are like the GNU Emacs `version-control' variable (*note
2898 Backup Names: (emacs)Backup Names, for more information on backup
2899 versions in Emacs). They also recognize synonyms that are more
2900 descriptive. The valid values are listed below; unique abbreviations
2905 Always make numbered backups.
2909 Make numbered backups of files that already have them, simple
2910 backups of the others. This is the default.
2914 Always make simple backups.
2916 You can also tell `patch' to prepend a prefix, such as a directory
2917 name, to produce backup file names. The `--prefix=PREFIX' (`-B
2918 PREFIX') option makes backup files by prepending PREFIX to them. The
2919 `--basename-prefix=PREFIX' (`-Y PREFIX') prepends PREFIX to the last
2920 file name component of backup file names instead; for example, `-Y ~'
2921 causes the backup name for `dir/file.c' to be `dir/~file.c'. If you
2922 use either of these prefix options, the suffix-based options are
2925 If you specify the output file with the `-o' option, that file is
2926 the one that is backed up, not the input file.
2928 Options that affect the names of backup files do not affect whether
2929 backups are made. For example, if you specify the
2930 `--no-backup-if-mismatch' option, none of the options described in this
2931 section have any affect, because no backups are made.
2933 ---------- Footnotes ----------
2935 (1) A coding error in GNU `patch' version 2.5.4 causes it to always
2936 use `~', but this should be fixed in the next release.
2939 File: diffutils.info-t, Node: Reject Names, Next: patch Messages, Prev: Backup Names, Up: Merging with patch
2941 10.10 Reject File Names
2942 =======================
2944 The names for reject files (files containing patches that `patch' could
2945 not find a place to apply) are normally the name of the output file
2946 with `.rej' appended (or `#' if using `.rej' would make the backup file
2949 Alternatively, you can tell `patch' to place all of the rejected
2950 patches in a single file. The `-r REJECT-FILE' or
2951 `--reject-file=REJECT-FILE' option uses REJECT-FILE as the reject file
2955 File: diffutils.info-t, Node: patch Messages, Next: patch and POSIX, Prev: Reject Names, Up: Merging with patch
2957 10.11 Messages and Questions from `patch'
2958 =========================================
2960 `patch' can produce a variety of messages, especially if it has trouble
2961 decoding its input. In a few situations where it's not sure how to
2962 proceed, `patch' normally prompts you for more information from the
2963 keyboard. There are options to produce more or fewer messages, to have
2964 it not ask for keyboard input, and to affect the way that file names
2965 are quoted in messages.
2969 * More or Fewer Messages:: Controlling the verbosity of `patch'.
2970 * patch and Keyboard Input:: Inhibiting keyboard input.
2971 * patch Quoting Style:: Quoting file names in diagnostics.
2973 `patch' exits with status 0 if all hunks are applied successfully, 1
2974 if some hunks cannot be applied, and 2 if there is more serious trouble.
2975 When applying a set of patches in a loop, you should check the exit
2976 status, so you don't apply a later patch to a partially patched file.
2979 File: diffutils.info-t, Node: More or Fewer Messages, Next: patch and Keyboard Input, Up: patch Messages
2981 10.11.1 Controlling the Verbosity of `patch'
2982 --------------------------------------------
2984 You can cause `patch' to produce more messages by using the `--verbose'
2985 option. For example, when you give this option, the message `Hmm...'
2986 indicates that `patch' is reading text in the patch file, attempting to
2987 determine whether there is a patch in that text, and if so, what kind
2990 You can inhibit all terminal output from `patch', unless an error
2991 occurs, by using the `-s', `--quiet', or `--silent' option.
2994 File: diffutils.info-t, Node: patch and Keyboard Input, Next: patch Quoting Style, Prev: More or Fewer Messages, Up: patch Messages
2996 10.11.2 Inhibiting Keyboard Input
2997 ---------------------------------
2999 There are two ways you can prevent `patch' from asking you any
3000 questions. The `--force' (`-f') option assumes that you know what you
3001 are doing. It causes `patch' to do the following:
3003 * Skip patches that do not contain file names in their headers.
3005 * Patch files even though they have the wrong version for the
3006 `Prereq:' line in the patch;
3008 * Assume that patches are not reversed even if they look like they
3011 The `--batch' (`-t') option is similar to `-f', in that it suppresses
3012 questions, but it makes somewhat different assumptions:
3014 * Skip patches that do not contain file names in their headers (the
3017 * Skip patches for which the file has the wrong version for the
3018 `Prereq:' line in the patch;
3020 * Assume that patches are reversed if they look like they are.
3023 File: diffutils.info-t, Node: patch Quoting Style, Prev: patch and Keyboard Input, Up: patch Messages
3025 10.11.3 `patch' Quoting Style
3026 -----------------------------
3028 When `patch' outputs a file name in a diagnostic message, it can format
3029 the name in any of several ways. This can be useful to output file
3030 names unambiguously, even if they contain punctuation or special
3031 characters like newlines. The `--quoting-style=WORD' option controls
3032 how names are output. The WORD should be one of the following:
3038 Quote names for the shell if they contain shell metacharacters or
3039 would cause ambiguous output.
3042 Quote names for the shell, even if they would normally not require
3046 Quote names as for a C language string.
3049 Quote as with `c' except omit the surrounding double-quote
3052 You can specify the default value of the `--quoting-style' option
3053 with the environment variable `QUOTING_STYLE'. If that environment
3054 variable is not set, the default value is `shell', but this default may
3055 change in a future version of `patch'.
3058 File: diffutils.info-t, Node: patch and POSIX, Next: patch and Tradition, Prev: patch Messages, Up: Merging with patch
3060 10.12 `patch' and the POSIX Standard
3061 ====================================
3063 If you specify the `--posix' option, or set the `POSIXLY_CORRECT'
3064 environment variable, `patch' conforms more strictly to the POSIX
3065 standard, as follows:
3067 * Take the first existing file from the list (old, new, index) when
3068 intuiting file names from diff headers. *Note Multiple Patches::.
3070 * Do not remove files that are removed by a diff. *Note Creating
3073 * Do not ask whether to get files from RCS, ClearCase, or SCCS.
3074 *Note Revision Control::.
3076 * Require that all options precede the files in the command line.
3078 * Do not backup files, even when there is a mismatch. *Note
3083 File: diffutils.info-t, Node: patch and Tradition, Prev: patch and POSIX, Up: Merging with patch
3085 10.13 GNU `patch' and Traditional `patch'
3086 =========================================
3088 The current version of GNU `patch' normally follows the POSIX standard.
3089 *Note patch and POSIX::, for the few exceptions to this general rule.
3091 Unfortunately, POSIX redefined the behavior of `patch' in several
3092 important ways. You should be aware of the following differences if
3093 you must interoperate with traditional `patch', or with GNU `patch'
3094 version 2.1 and earlier.
3096 * In traditional `patch', the `-p' option's operand was optional,
3097 and a bare `-p' was equivalent to `-p0'. The `-p' option now
3098 requires an operand, and `-p 0' is now equivalent to `-p0'. For
3099 maximum compatibility, use options like `-p0' and `-p1'.
3101 Also, traditional `patch' simply counted slashes when stripping
3102 path prefixes; `patch' now counts pathname components. That is, a
3103 sequence of one or more adjacent slashes now counts as a single
3104 slash. For maximum portability, avoid sending patches containing
3107 * In traditional `patch', backups were enabled by default. This
3108 behavior is now enabled with the `--backup' (`-b') option.
3110 Conversely, in POSIX `patch', backups are never made, even when
3111 there is a mismatch. In GNU `patch', this behavior is enabled
3112 with the `--no-backup-if-mismatch' option, or by conforming to
3115 The `-b SUFFIX' option of traditional `patch' is equivalent to the
3116 `-b -z SUFFIX' options of GNU `patch'.
3118 * Traditional `patch' used a complicated (and incompletely
3119 documented) method to intuit the name of the file to be patched
3120 from the patch header. This method did not conform to POSIX, and
3121 had a few gotchas. Now `patch' uses a different, equally
3122 complicated (but better documented) method that is optionally
3123 POSIX-conforming; we hope it has fewer gotchas. The two methods
3124 are compatible if the file names in the context diff header and the
3125 `Index:' line are all identical after prefix-stripping. Your
3126 patch is normally compatible if each header's file names all
3127 contain the same number of slashes.
3129 * When traditional `patch' asked the user a question, it sent the
3130 question to standard error and looked for an answer from the first
3131 file in the following list that was a terminal: standard error,
3132 standard output, `/dev/tty', and standard input. Now `patch'
3133 sends questions to standard output and gets answers from
3134 `/dev/tty'. Defaults for some answers have been changed so that
3135 `patch' never goes into an infinite loop when using default
3138 * Traditional `patch' exited with a status value that counted the
3139 number of bad hunks, or with status 1 if there was real trouble.
3140 Now `patch' exits with status 1 if some hunks failed, or with 2 if
3141 there was real trouble.
3143 * Limit yourself to the following options when sending instructions
3144 meant to be executed by anyone running GNU `patch', traditional
3145 `patch', or a `patch' that conforms to POSIX. Spaces are
3146 significant in the following list, and operands are required.
3162 File: diffutils.info-t, Node: Making Patches, Next: Invoking cmp, Prev: Merging with patch, Up: Top
3164 11 Tips for Making and Using Patches
3165 ************************************
3167 Use some common sense when making and using patches. For example, when
3168 sending bug fixes to a program's maintainer, send several small
3169 patches, one per independent subject, instead of one large,
3170 harder-to-digest patch that covers all the subjects.
3172 Here are some other things you should keep in mind if you are going
3173 to distribute patches for updating a software package.
3177 * Tips for Patch Producers:: Advice for making patches.
3178 * Tips for Patch Consumers:: Advice for using patches.
3179 * Avoiding Common Mistakes:: Avoiding common mistakes when using `patch'.
3180 * Generating Smaller Patches:: How to generate smaller patches.
3183 File: diffutils.info-t, Node: Tips for Patch Producers, Next: Tips for Patch Consumers, Up: Making Patches
3185 11.1 Tips for Patch Producers
3186 =============================
3188 To create a patch that changes an older version of a package into a
3189 newer version, first make a copy of the older and newer versions in
3190 adjacent subdirectories. It is common to do that by unpacking `tar'
3191 archives of the two versions.
3193 To generate the patch, use the command `diff -Naur OLD NEW' where
3194 OLD and NEW identify the old and new directories. The names OLD and
3195 NEW should not contain any slashes. The `-N' option lets the patch
3196 create and remove files; `-a' lets the patch update non-text files; `-u'
3197 generates useful time stamps and enough context; and `-r' lets the
3198 patch update subdirectories. Here is an example command, using Bourne
3201 diff -Naur gcc-3.0.3 gcc-3.0.4
3203 Tell your recipients how to apply the patches. This should include
3204 which working directory to use, and which `patch' options to use; the
3205 option `-p1' is recommended. Test your procedure by pretending to be a
3206 recipient and applying your patches to a copy of the original files.
3208 *Note Avoiding Common Mistakes::, for how to avoid common mistakes
3209 when generating a patch.
3212 File: diffutils.info-t, Node: Tips for Patch Consumers, Next: Avoiding Common Mistakes, Prev: Tips for Patch Producers, Up: Making Patches
3214 11.2 Tips for Patch Consumers
3215 =============================
3217 A patch producer should tell recipients how to apply the patches, so
3218 the first rule of thumb for a patch consumer is to follow the
3219 instructions supplied with the patch.
3221 GNU `diff' can analyze files with arbitrarily long lines and files
3222 that end in incomplete lines. However, older versions of `patch'
3223 cannot patch such files. If you are having trouble applying such
3224 patches, try upgrading to a recent version of GNU `patch'.
3227 File: diffutils.info-t, Node: Avoiding Common Mistakes, Next: Generating Smaller Patches, Prev: Tips for Patch Consumers, Up: Making Patches
3229 11.3 Avoiding Common Mistakes
3230 =============================
3232 When producing a patch for multiple files, apply `diff' to directories
3233 whose names do not have slashes. This reduces confusion when the patch
3234 consumer specifies the `-pNUMBER' option, since this option can have
3235 surprising results when the old and new file names have different
3236 numbers of slashes. For example, do not send a patch with a header
3237 that looks like this:
3239 diff -Naur v2.0.29/prog/README prog/README
3240 --- v2.0.29/prog/README 2002-03-10 23:30:39.942229878 -0800
3241 +++ prog/README 2002-03-17 20:49:32.442260588 -0800
3243 because the two file names have different numbers of slashes, and
3244 different versions of `patch' interpret the file names differently. To
3245 avoid confusion, send output that looks like this instead:
3247 diff -Naur v2.0.29/prog/README v2.0.30/prog/README
3248 --- v2.0.29/prog/README 2002-03-10 23:30:39.942229878 -0800
3249 +++ v2.0.30/prog/README 2002-03-17 20:49:32.442260588 -0800
3251 Make sure you have specified the file names correctly, either in a
3252 context diff header or with an `Index:' line. Take care to not send out
3253 reversed patches, since these make people wonder whether they have
3254 already applied the patch.
3256 Avoid sending patches that compare backup file names like
3257 `README.orig' or `README~', since this might confuse `patch' into
3258 patching a backup file instead of the real file. Instead, send patches
3259 that compare the same base file names in different directories, e.g.
3260 `old/README' and `new/README'.
3262 To save people from partially applying a patch before other patches
3263 that should have gone before it, you can make the first patch in the
3264 patch file update a file with a name like `patchlevel.h' or
3265 `version.c', which contains a patch level or version number. If the
3266 input file contains the wrong version number, `patch' will complain
3269 An even clearer way to prevent this problem is to put a `Prereq:'
3270 line before the patch. If the leading text in the patch file contains a
3271 line that starts with `Prereq:', `patch' takes the next word from that
3272 line (normally a version number) and checks whether the next input file
3273 contains that word, preceded and followed by either white space or a
3274 newline. If not, `patch' prompts you for confirmation before
3275 proceeding. This makes it difficult to accidentally apply patches in
3279 File: diffutils.info-t, Node: Generating Smaller Patches, Prev: Avoiding Common Mistakes, Up: Making Patches
3281 11.4 Generating Smaller Patches
3282 ===============================
3284 The simplest way to generate a patch is to use `diff -Naur' (*note Tips
3285 for Patch Producers::), but you might be able to reduce the size of the
3286 patch by renaming or removing some files before making the patch. If
3287 the older version of the package contains any files that the newer
3288 version does not, or if any files have been renamed between the two
3289 versions, make a list of `rm' and `mv' commands for the user to execute
3290 in the old version directory before applying the patch. Then run those
3291 commands yourself in the scratch directory.
3293 If there are any files that you don't need to include in the patch
3294 because they can easily be rebuilt from other files (for example,
3295 `TAGS' and output from `yacc' and `makeinfo'), exclude them from the
3296 patch by giving `diff' the `-x PATTERN' option (*note Comparing
3297 Directories::). If you want your patch to modify a derived file
3298 because your recipients lack tools to build it, make sure that the
3299 patch for the derived file follows any patches for files that it
3300 depends on, so that the recipients' time stamps will not confuse `make'.
3302 Now you can create the patch using `diff -Naur'. Make sure to
3303 specify the scratch directory first and the newer directory second.
3305 Add to the top of the patch a note telling the user any `rm' and
3306 `mv' commands to run before applying the patch. Then you can remove
3307 the scratch directory.
3309 You can also shrink the patch size by using fewer lines of context,
3310 but bear in mind that `patch' typically needs at least two lines for
3311 proper operation when patches do not exactly match the input files.
3314 File: diffutils.info-t, Node: Invoking cmp, Next: Invoking diff, Prev: Making Patches, Up: Top
3319 The `cmp' command compares two files, and if they differ, tells the
3320 first byte and line number where they differ or reports that one file
3321 is a prefix of the other. Bytes and lines are numbered starting with
3322 1. The arguments of `cmp' are as follows:
3324 cmp OPTIONS... FROM-FILE [TO-FILE [FROM-SKIP [TO-SKIP]]]
3326 The file name `-' is always the standard input. `cmp' also uses the
3327 standard input if one file name is omitted. The FROM-SKIP and TO-SKIP
3328 operands specify how many bytes to ignore at the start of each file;
3329 they are equivalent to the `--ignore-initial=FROM-SKIP:TO-SKIP' option.
3331 By default, `cmp' outputs nothing if the two files have the same
3332 contents. If one file is a prefix of the other, `cmp' prints to
3333 standard error a message of the following form:
3335 cmp: EOF on SHORTER-FILE
3337 Otherwise, `cmp' prints to standard output a message of the
3340 FROM-FILE TO-FILE differ: char BYTE-NUMBER, line LINE-NUMBER
3342 The message formats can differ outside the POSIX locale. Also,
3343 POSIX allows the EOF message to be followed by a blank and some
3344 additional information.
3346 An exit status of 0 means no differences were found, 1 means some
3347 differences were found, and 2 means trouble.
3351 * cmp Options:: Summary of options to `cmp'.
3354 File: diffutils.info-t, Node: cmp Options, Up: Invoking cmp
3356 12.1 Options to `cmp'
3357 =====================
3359 Below is a summary of all of the options that GNU `cmp' accepts. Most
3360 options have two equivalent names, one of which is a single letter
3361 preceded by `-', and the other of which is a long name preceded by
3362 `--'. Multiple single letter options (unless they take an argument)
3363 can be combined into a single command line word: `-bl' is equivalent to
3368 Print the differing bytes. Display control bytes as a `^'
3369 followed by a letter of the alphabet and precede bytes that have
3370 the high bit set with `M-' (which stands for "meta").
3373 Output a summary of usage and then exit.
3376 `--ignore-initial=SKIP'
3377 Ignore any differences in the first SKIP bytes of the input files.
3378 Treat files with fewer than SKIP bytes as if they are empty. If
3379 SKIP is of the form `FROM-SKIP:TO-SKIP', skip the first FROM-SKIP
3380 bytes of the first input file and the first TO-SKIP bytes of the
3385 Output the (decimal) byte numbers and (octal) values of all
3386 differing bytes, instead of the default standard output. Each
3387 output line contains a differing byte's number relative to the
3388 start of the input, followed by the differing byte values. Byte
3389 numbers start at 1. Also, output the EOF message if one file is
3390 shorter than the other.
3394 Compare at most COUNT input bytes.
3399 Do not print anything; only return an exit status indicating
3400 whether the files differ.
3404 Output version information and then exit.
3406 In the above table, operands that are byte counts are normally
3407 decimal, but may be preceded by `0' for octal and `0x' for hexadecimal.
3409 A byte count can be followed by a suffix to specify a multiple of
3410 that count; in this case an omitted integer is understood to be 1. A
3411 bare size letter, or one followed by `iB', specifies a multiple using
3412 powers of 1024. A size letter followed by `B' specifies powers of 1000
3413 instead. For example, `-n 4M' and `-n 4MiB' are equivalent to `-n
3414 4194304', whereas `-n 4MB' is equivalent to `-n 4000000'. This
3415 notation is upward compatible with the SI prefixes
3416 (http://www.bipm.fr/enus/3_SI/si-prefixes.html) for decimal multiples
3417 and with the IEC 60027-2 prefixes for binary multiples
3418 (http://physics.nist.gov/cuu/Units/binary.html).
3420 The following suffixes are defined. Large sizes like `1Y' may be
3421 rejected by your computer due to limitations of its arithmetic.
3424 kilobyte: 10^3 = 1000.
3429 kibibyte: 2^10 = 1024. `K' is special: the SI prefix is `k' and
3430 the IEC 60027-2 prefix is `Ki', but tradition and POSIX use `k' to
3434 megabyte: 10^6 = 1,000,000.
3438 mebibyte: 2^20 = 1,048,576.
3441 gigabyte: 10^9 = 1,000,000,000.
3445 gibibyte: 2^30 = 1,073,741,824.
3448 terabyte: 10^12 = 1,000,000,000,000.
3452 tebibyte: 2^40 = 1,099,511,627,776.
3455 petabyte: 10^15 = 1,000,000,000,000,000.
3459 pebibyte: 2^50 = 1,125,899,906,842,624.
3462 exabyte: 10^18 = 1,000,000,000,000,000,000.
3466 exbibyte: 2^60 = 1,152,921,504,606,846,976.
3469 zettabyte: 10^21 = 1,000,000,000,000,000,000,000
3473 2^70 = 1,180,591,620,717,411,303,424. (`Zi' is a GNU extension to
3477 yottabyte: 10^24 = 1,000,000,000,000,000,000,000,000.
3481 2^80 = 1,208,925,819,614,629,174,706,176. (`Yi' is a GNU
3482 extension to IEC 60027-2.)
3485 File: diffutils.info-t, Node: Invoking diff, Next: Invoking diff3, Prev: Invoking cmp, Up: Top
3490 The format for running the `diff' command is:
3492 diff OPTIONS... FILES...
3494 In the simplest case, two file names FROM-FILE and TO-FILE are
3495 given, and `diff' compares the contents of FROM-FILE and TO-FILE. A
3496 file name of `-' stands for text read from the standard input. As a
3497 special case, `diff - -' compares a copy of standard input to itself.
3499 If one file is a directory and the other is not, `diff' compares the
3500 file in the directory whose name is that of the non-directory. The
3501 non-directory file must not be `-'.
3503 If two file names are given and both are directories, `diff'
3504 compares corresponding files in both directories, in alphabetical
3505 order; this comparison is not recursive unless the `--recursive' (`-r')
3506 option is given. `diff' never compares the actual contents of a
3507 directory as if it were a file. The file that is fully specified may
3508 not be standard input, because standard input is nameless and the
3509 notion of "file with the same name" does not apply.
3511 If the `--from-file=FILE' option is given, the number of file names
3512 is arbitrary, and FILE is compared to each named file. Similarly, if
3513 the `--to-file=FILE' option is given, each named file is compared to
3516 `diff' options begin with `-', so normally file names may not begin
3517 with `-'. However, `--' as an argument by itself treats the remaining
3518 arguments as file names even if they begin with `-'.
3520 An exit status of 0 means no differences were found, 1 means some
3521 differences were found, and 2 means trouble. Normally, differing
3522 binary files count as trouble, but this can be altered by using the
3523 `--text' (`-a') option, or the `-q' or `--brief' option.
3527 * diff Options:: Summary of options to `diff'.
3530 File: diffutils.info-t, Node: diff Options, Up: Invoking diff
3532 13.1 Options to `diff'
3533 ======================
3535 Below is a summary of all of the options that GNU `diff' accepts. Most
3536 options have two equivalent names, one of which is a single letter
3537 preceded by `-', and the other of which is a long name preceded by
3538 `--'. Multiple single letter options (unless they take an argument)
3539 can be combined into a single command line word: `-ac' is equivalent to
3540 `-a -c'. Long named options can be abbreviated to any unique prefix of
3541 their name. Brackets ([ and ]) indicate that an option takes an
3546 Treat all files as text and compare them line-by-line, even if they
3547 do not seem to be text. *Note Binary::.
3550 `--ignore-space-change'
3551 Ignore changes in amount of white space. *Note White Space::.
3554 `--ignore-blank-lines'
3555 Ignore changes that just insert or delete blank lines. *Note
3559 Read and write data in binary mode. *Note Binary::.
3562 Use the context output format, showing three lines of context.
3563 *Note Context Format::.
3567 Use the context output format, showing LINES (an integer) lines of
3568 context, or three if LINES is not given. *Note Context Format::.
3569 For proper operation, `patch' typically needs at least two lines of
3572 For compatibility `diff' also supports an obsolete option syntax
3573 `-LINES' that has effect when combined with `-c', `-p', or `-u'.
3574 New scripts should use `-U LINES' (`-C LINES') instead.
3576 `--changed-group-format=FORMAT'
3577 Use FORMAT to output a line group containing differing lines from
3578 both files in if-then-else format. *Note Line Group Formats::.
3582 Change the algorithm perhaps find a smaller set of changes. This
3583 makes `diff' slower (sometimes much slower). *Note diff
3588 Make merged `#ifdef' format output, conditional on the preprocessor
3589 macro NAME. *Note If-then-else::.
3593 Make output that is a valid `ed' script. *Note ed Scripts::.
3596 `--ignore-tab-expansion'
3597 Ignore changes due to tab expansion. *Note White Space::.
3601 Make output that looks vaguely like an `ed' script but has changes
3602 in the order they appear in the file. *Note Forward ed::.
3605 `--show-function-line=REGEXP'
3606 In context and unified format, for each hunk of differences, show
3607 some of the last preceding line that matches REGEXP. *Note
3608 Specified Headings::.
3611 Compare FILE to each operand; FILE may be a directory.
3614 Output a summary of usage and then exit.
3616 `--horizon-lines=LINES'
3617 Do not discard the last LINES lines of the common prefix and the
3618 first LINES lines of the common suffix. *Note diff Performance::.
3622 Ignore changes in case; consider upper- and lower-case letters
3623 equivalent. *Note Case Folding::.
3626 `--ignore-matching-lines=REGEXP'
3627 Ignore changes that just insert or delete lines that match REGEXP.
3628 *Note Specified Lines::.
3630 `--ignore-file-name-case'
3631 Ignore case when comparing file names. For example, recursive
3632 comparison of `d' to `e' might compare the contents of `d/Init'
3633 and `e/inIt'. At the top level, `diff d inIt' might compare the
3634 contents of `d/Init' and `inIt'. *Note Comparing Directories::.
3638 Pass the output through `pr' to paginate it. *Note Pagination::.
3642 Use LABEL instead of the file name in the context format (*note
3643 Context Format::) and unified format (*note Unified Format::)
3644 headers. *Note RCS::.
3647 Print only the left column of two common lines in side by side
3648 format. *Note Side by Side Format::.
3650 `--line-format=FORMAT'
3651 Use FORMAT to output all input lines in if-then-else format.
3652 *Note Line Formats::.
3656 Output RCS-format diffs; like `-f' except that each command
3657 specifies the number of lines affected. *Note RCS::.
3661 If one file is missing, treat it as present but empty. *Note
3662 Comparing Directories::.
3664 `--new-group-format=FORMAT'
3665 Use FORMAT to output a group of lines taken from just the second
3666 file in if-then-else format. *Note Line Group Formats::.
3668 `--new-line-format=FORMAT'
3669 Use FORMAT to output a line taken from just the second file in
3670 if-then-else format. *Note Line Formats::.
3673 Act on symbolic links themselves instead of what they point to.
3675 `--old-group-format=FORMAT'
3676 Use FORMAT to output a group of lines taken from just the first
3677 file in if-then-else format. *Note Line Group Formats::.
3679 `--old-line-format=FORMAT'
3680 Use FORMAT to output a line taken from just the first file in
3681 if-then-else format. *Note Line Formats::.
3685 Show which C function each change is in. *Note C Function
3690 Report only whether the files differ, not the details of the
3691 differences. *Note Brief::.
3695 When comparing directories, recursively compare any subdirectories
3696 found. *Note Comparing Directories::.
3699 `--report-identical-files'
3700 Report when two files are the same. *Note Comparing Directories::.
3703 `--starting-file=FILE'
3704 When comparing directories, start with the file FILE. This is
3705 used for resuming an aborted comparison. *Note Comparing
3708 `--speed-large-files'
3709 Use heuristics to speed handling of large files that have numerous
3710 scattered small changes. *Note diff Performance::.
3712 `--strip-trailing-cr'
3713 Strip any trailing carriage return at the end of an input line.
3716 `--suppress-common-lines'
3717 Do not print common lines in side by side format. *Note Side by
3722 Expand tabs to spaces in the output, to preserve the alignment of
3723 tabs in the input files. *Note Tabs::.
3727 Output a tab rather than a space before the text of a line in
3728 normal or context format. This causes the alignment of tabs in
3729 the line to look normal. *Note Tabs::.
3732 Assume that tab stops are set every COLUMNS (default 8) print
3733 columns. *Note Tabs::.
3735 `--suppress-blank-empty'
3736 Suppress any blanks before newlines when printing the
3737 representation of an empty line, when outputting normal, context,
3738 or unified format. *Note Trailing Blanks::.
3741 Compare each operand to FILE; FILE may be a directory.
3744 Use the unified output format, showing three lines of context.
3745 *Note Unified Format::.
3747 `--unchanged-group-format=FORMAT'
3748 Use FORMAT to output a group of common lines taken from both files
3749 in if-then-else format. *Note Line Group Formats::.
3751 `--unchanged-line-format=FORMAT'
3752 Use FORMAT to output a line common to both files in if-then-else
3753 format. *Note Line Formats::.
3755 `--unidirectional-new-file'
3756 If a first file is missing, treat it as present but empty. *Note
3757 Comparing Directories::.
3761 Use the unified output format, showing LINES (an integer) lines of
3762 context, or three if LINES is not given. *Note Unified Format::.
3763 For proper operation, `patch' typically needs at least two lines of
3766 On older systems, `diff' supports an obsolete option `-LINES' that
3767 has effect when combined with `-u'. POSIX 1003.1-2001 (*note
3768 Standards conformance::) does not allow this; use `-U LINES'
3773 Output version information and then exit.
3776 `--ignore-all-space'
3777 Ignore white space when comparing lines. *Note White Space::.
3781 Output at most COLUMNS (default 130) print columns per line in
3782 side by side format. *Note Side by Side Format::.
3786 When comparing directories, ignore files and subdirectories whose
3787 basenames match PATTERN. *Note Comparing Directories::.
3790 `--exclude-from=FILE'
3791 When comparing directories, ignore files and subdirectories whose
3792 basenames match any pattern contained in FILE. *Note Comparing
3797 Use the side by side output format. *Note Side by Side Format::.
3800 `--ignore-trailing-space'
3801 Ignore white space at line end. *Note White Space::.
3804 File: diffutils.info-t, Node: Invoking diff3, Next: Invoking patch, Prev: Invoking diff, Up: Top
3809 The `diff3' command compares three files and outputs descriptions of
3810 their differences. Its arguments are as follows:
3812 diff3 OPTIONS... MINE OLDER YOURS
3814 The files to compare are MINE, OLDER, and YOURS. At most one of
3815 these three file names may be `-', which tells `diff3' to read the
3816 standard input for that file.
3818 An exit status of 0 means `diff3' was successful, 1 means some
3819 conflicts were found, and 2 means trouble.
3823 * diff3 Options:: Summary of options to `diff3'.
3826 File: diffutils.info-t, Node: diff3 Options, Up: Invoking diff3
3828 14.1 Options to `diff3'
3829 =======================
3831 Below is a summary of all of the options that GNU `diff3' accepts.
3832 Multiple single letter options (unless they take an argument) can be
3833 combined into a single command line argument.
3837 Treat all files as text and compare them line-by-line, even if they
3838 do not appear to be text. *Note Binary::.
3842 Incorporate all unmerged changes from OLDER to YOURS into MINE,
3843 surrounding conflicts with bracket lines. *Note Marking
3846 `--diff-program=PROGRAM'
3847 Use the compatible comparison program PROGRAM to compare files
3852 Generate an `ed' script that incorporates all the changes from
3853 OLDER to YOURS into MINE. *Note Which Changes::.
3857 Like `-e', except bracket lines from overlapping changes' first
3858 and third files. *Note Marking Conflicts::. With `-E', an
3859 overlapping change looks like this:
3868 Output a summary of usage and then exit.
3871 Generate `w' and `q' commands at the end of the `ed' script for
3872 System V compatibility. This option must be combined with one of
3873 the `-AeExX3' options, and may not be combined with `-m'. *Note
3874 Saving the Changed File::.
3877 Use the label LABEL for the brackets output by the `-A', `-E' and
3878 `-X' options. This option may be given up to three times, one for
3879 each input file. The default labels are the names of the input
3880 files. Thus `diff3 --label X --label Y --label Z -m A B C' acts
3881 like `diff3 -m A B C', except that the output looks like it came
3882 from files named `X', `Y' and `Z' rather than from files named
3883 `A', `B' and `C'. *Note Marking Conflicts::.
3887 Apply the edit script to the first file and send the result to
3888 standard output. Unlike piping the output from `diff3' to `ed',
3889 this works even for binary files and incomplete lines. `-A' is
3890 assumed if no edit script option is specified. *Note Bypassing
3893 `--strip-trailing-cr'
3894 Strip any trailing carriage return at the end of an input line.
3899 Output a tab rather than two spaces before the text of a line in
3900 normal format. This causes the alignment of tabs in the line to
3901 look normal. *Note Tabs::.
3905 Output version information and then exit.
3909 Like `-e', except output only the overlapping changes. *Note
3913 Like `-E', except output only the overlapping changes. In other
3914 words, like `-x', except bracket changes as in `-E'. *Note
3915 Marking Conflicts::.
3919 Like `-e', except output only the nonoverlapping changes. *Note
3923 File: diffutils.info-t, Node: Invoking patch, Next: Invoking sdiff, Prev: Invoking diff3, Up: Top
3928 Normally `patch' is invoked like this:
3932 The full format for invoking `patch' is:
3934 patch OPTIONS... [ORIGFILE [PATCHFILE]]
3936 You can also specify where to read the patch from with the `-i
3937 PATCHFILE' or `--input=PATCHFILE' option. If you do not specify
3938 PATCHFILE, or if PATCHFILE is `-', `patch' reads the patch (that is,
3939 the `diff' output) from the standard input.
3941 If you do not specify an input file on the command line, `patch'
3942 tries to intuit from the "leading text" (any text in the patch that
3943 comes before the `diff' output) which file to edit. *Note Multiple
3946 By default, `patch' replaces the original input file with the
3947 patched version, possibly after renaming the original file into a
3948 backup file (*note Backup Names::, for a description of how `patch'
3949 names backup files). You can also specify where to put the output with
3950 the `-o FILE' or `--output=FILE' option; however, do not use this option
3951 if FILE is one of the input files.
3955 * patch Options:: Summary table of options to `patch'.
3958 File: diffutils.info-t, Node: patch Options, Up: Invoking patch
3960 15.1 Options to `patch'
3961 =======================
3963 Here is a summary of all of the options that GNU `patch' accepts.
3964 *Note patch and Tradition::, for which of these options are safe to use
3965 in older versions of `patch'.
3967 Multiple single-letter options that do not take an argument can be
3968 combined into a single command line argument with only one dash.
3972 Back up the original contents of each file, even if backups would
3973 normally not be made. *Note Backups::.
3977 Prepend PREFIX to backup file names. *Note Backup Names::.
3979 `--backup-if-mismatch'
3980 Back up the original contents of each file if the patch does not
3981 exactly match the file. This is the default behavior when not
3982 conforming to POSIX. *Note Backups::.
3985 Read and write all files in binary mode, except for standard output
3986 and `/dev/tty'. This option has no effect on POSIX-conforming
3987 systems like GNU/Linux. On systems where this option makes a
3988 difference, the patch should be generated by `diff -a --binary'.
3993 Interpret the patch file as a context diff. *Note patch Input::.
3996 `--directory=DIRECTORY'
3997 Make directory DIRECTORY the current directory for interpreting
3998 both file names in the patch file, and file names given as
3999 arguments to other options. *Note patch Directories::.
4003 Make merged if-then-else output using NAME. *Note If-then-else::.
4006 Print the results of applying the patches without actually changing
4007 any files. *Note Dry Runs::.
4011 Interpret the patch file as an `ed' script. *Note patch Input::.
4014 `--remove-empty-files'
4015 Remove output files that are empty after the patches have been
4016 applied. *Note Creating and Removing::.
4020 Assume that the user knows exactly what he or she is doing, and do
4021 not ask any questions. *Note patch Messages::.
4025 Set the maximum fuzz factor to LINES. *Note Inexact::.
4029 If NUM is positive, get input files from a revision control system
4030 as necessary; if zero, do not get the files; if negative, ask the
4031 user whether to get the files. *Note Revision Control::.
4034 Output a summary of usage and then exit.
4038 Read the patch from PATCHFILE rather than from standard input.
4039 *Note patch Options::.
4042 `--ignore-white-space'
4043 Let any sequence of blanks (spaces or tabs) in the patch file match
4044 any sequence of blanks in the input file. *Note Changed White
4049 Interpret the patch file as a normal diff. *Note patch Input::.
4053 Ignore patches that `patch' thinks are reversed or already applied.
4054 See also `-R'. *Note Reversed Patches::.
4056 `--no-backup-if-mismatch'
4057 Do not back up the original contents of files. This is the default
4058 behavior when conforming to POSIX. *Note Backups::.
4062 Use FILE as the output file name. *Note patch Options::.
4066 Set the file name strip count to NUMBER. *Note patch
4070 Conform to POSIX, as if the `POSIXLY_CORRECT' environment variable
4071 had been set. *Note patch and POSIX::.
4073 `--quoting-style=WORD'
4074 Use style WORD to quote names in diagnostics, as if the
4075 `QUOTING_STYLE' environment variable had been set to WORD. *Note
4076 patch Quoting Style::.
4079 `--reject-file=REJECT-FILE'
4080 Use REJECT-FILE as the reject file name. *Note Reject Names::.
4084 Assume that this patch was created with the old and new files
4085 swapped. *Note Reversed Patches::.
4090 Work silently unless an error occurs. *Note patch Messages::.
4094 Do not ask any questions. *Note patch Messages::.
4098 Set the modification and access times of patched files from time
4099 stamps given in context diff headers, assuming that the context
4100 diff headers use local time. *Note Patching Time Stamps::.
4104 Interpret the patch file as a unified diff. *Note patch Input::.
4108 Output version information and then exit.
4111 `--version=control=BACKUP-STYLE'
4112 Select the naming convention for backup file names. *Note Backup
4116 Print more diagnostics than usual. *Note patch Messages::.
4120 Set internal debugging flags. Of interest only to `patch'
4124 `--basename-prefix=PREFIX'
4125 Prepend PREFIX to base names of backup files. *Note Backup
4130 Use SUFFIX as the backup extension instead of `.orig' or `~'.
4131 *Note Backup Names::.
4135 Set the modification and access times of patched files from time
4136 stamps given in context diff headers, assuming that the context
4137 diff headers use UTC. *Note Patching Time Stamps::.
4141 File: diffutils.info-t, Node: Invoking sdiff, Next: Standards conformance, Prev: Invoking patch, Up: Top
4146 The `sdiff' command merges two files and interactively outputs the
4147 results. Its arguments are as follows:
4149 sdiff -o OUTFILE OPTIONS... FROM-FILE TO-FILE
4151 This merges FROM-FILE with TO-FILE, with output to OUTFILE. If
4152 FROM-FILE is a directory and TO-FILE is not, `sdiff' compares the file
4153 in FROM-FILE whose file name is that of TO-FILE, and vice versa.
4154 FROM-FILE and TO-FILE may not both be directories.
4156 `sdiff' options begin with `-', so normally FROM-FILE and TO-FILE
4157 may not begin with `-'. However, `--' as an argument by itself treats
4158 the remaining arguments as file names even if they begin with `-'. You
4159 may not use `-' as an input file.
4161 `sdiff' without `--output' (`-o') produces a side-by-side
4162 difference. This usage is obsolete; use the `--side-by-side' (`-y')
4163 option of `diff' instead.
4165 An exit status of 0 means no differences were found, 1 means some
4166 differences were found, and 2 means trouble.
4170 * sdiff Options:: Summary of options to `diff'.
4173 File: diffutils.info-t, Node: sdiff Options, Up: Invoking sdiff
4175 16.1 Options to `sdiff'
4176 =======================
4178 Below is a summary of all of the options that GNU `sdiff' accepts.
4179 Each option has two equivalent names, one of which is a single letter
4180 preceded by `-', and the other of which is a long name preceded by
4181 `--'. Multiple single letter options (unless they take an argument)
4182 can be combined into a single command line argument. Long named
4183 options can be abbreviated to any unique prefix of their name.
4187 Treat all files as text and compare them line-by-line, even if they
4188 do not appear to be text. *Note Binary::.
4191 `--ignore-space-change'
4192 Ignore changes in amount of white space. *Note White Space::.
4195 `--ignore-blank-lines'
4196 Ignore changes that just insert or delete blank lines. *Note
4201 Change the algorithm to perhaps find a smaller set of changes.
4202 This makes `sdiff' slower (sometimes much slower). *Note diff
4205 `--diff-program=PROGRAM'
4206 Use the compatible comparison program PROGRAM to compare files
4210 `--ignore-tab-expansion'
4211 Ignore changes due to tab expansion. *Note White Space::.
4214 Output a summary of usage and then exit.
4218 Ignore changes in case; consider upper- and lower-case to be the
4219 same. *Note Case Folding::.
4222 `--ignore-matching-lines=REGEXP'
4223 Ignore changes that just insert or delete lines that match REGEXP.
4224 *Note Specified Lines::.
4228 Print only the left column of two common lines. *Note Side by
4233 Put merged output into FILE. This option is required for merging.
4236 `--suppress-common-lines'
4237 Do not print common lines. *Note Side by Side Format::.
4239 `--speed-large-files'
4240 Use heuristics to speed handling of large files that have numerous
4241 scattered small changes. *Note diff Performance::.
4243 `--strip-trailing-cr'
4244 Strip any trailing carriage return at the end of an input line.
4249 Expand tabs to spaces in the output, to preserve the alignment of
4250 tabs in the input files. *Note Tabs::.
4253 Assume that tab stops are set every COLUMNS (default 8) print
4254 columns. *Note Tabs::.
4258 Output version information and then exit.
4262 Output at most COLUMNS (default 130) print columns per line.
4263 *Note Side by Side Format::. Note that for historical reasons,
4264 this option is `-W' in `diff', `-w' in `sdiff'.
4267 `--ignore-all-space'
4268 Ignore white space when comparing lines. *Note White Space::.
4269 Note that for historical reasons, this option is `-w' in `diff',
4273 `--ignore-trailing-space'
4274 Ignore white space at line end. *Note White Space::.
4277 File: diffutils.info-t, Node: Standards conformance, Next: Projects, Prev: Invoking sdiff, Up: Top
4279 17 Standards conformance
4280 ************************
4282 In a few cases, the GNU utilities' default behavior is incompatible
4283 with the POSIX standard. To suppress these incompatibilities, define
4284 the `POSIXLY_CORRECT' environment variable. Unless you are checking
4285 for POSIX conformance, you probably do not need to define
4288 Normally options and operands can appear in any order, and programs
4289 act as if all the options appear before any operands. For example,
4290 `diff lao tzu -C 2' acts like `diff -C 2 lao tzu', since `2' is an
4291 option-argument of `-C'. However, if the `POSIXLY_CORRECT' environment
4292 variable is set, options must appear before operands, unless otherwise
4293 specified for a particular command.
4295 Newer versions of POSIX are occasionally incompatible with older
4296 versions. For example, older versions of POSIX allowed the command
4297 `diff -c -10' to have the same meaning as `diff -C 10', but POSIX
4298 1003.1-2001 `diff' no longer allows digit-string options like `-10'.
4300 The GNU utilities normally conform to the version of POSIX that is
4301 standard for your system. To cause them to conform to a different
4302 version of POSIX, define the `_POSIX2_VERSION' environment variable to
4303 a value of the form YYYYMM specifying the year and month the standard
4304 was adopted. Two values are currently supported for `_POSIX2_VERSION':
4305 `199209' stands for POSIX 1003.2-1992, and `200112' stands for POSIX
4306 1003.1-2001. For example, if you are running older software that
4307 assumes an older version of POSIX and uses `diff -c -10', you can work
4308 around the compatibility problems by setting `_POSIX2_VERSION=199209'
4309 in your environment.
4312 File: diffutils.info-t, Node: Projects, Next: Copying This Manual, Prev: Standards conformance, Up: Top
4317 Here are some ideas for improving GNU `diff' and `patch'. The GNU
4318 project has identified some improvements as potential programming
4319 projects for volunteers. You can also help by reporting any bugs that
4322 If you are a programmer and would like to contribute something to the
4323 GNU project, please consider volunteering for one of these projects.
4324 If you are seriously contemplating work, please write to <gvc@gnu.org>
4325 to coordinate with other volunteers.
4329 * Shortcomings:: Suggested projects for improvements.
4330 * Bugs:: Reporting bugs.
4333 File: diffutils.info-t, Node: Shortcomings, Next: Bugs, Up: Projects
4335 18.1 Suggested Projects for Improving GNU `diff' and `patch'
4336 ============================================================
4338 One should be able to use GNU `diff' to generate a patch from any pair
4339 of directory trees, and given the patch and a copy of one such tree,
4340 use `patch' to generate a faithful copy of the other. Unfortunately,
4341 some changes to directory trees cannot be expressed using current patch
4342 formats; also, `patch' does not handle some of the existing formats.
4343 These shortcomings motivate the following suggested projects.
4347 * Internationalization:: Handling multibyte and varying-width characters.
4348 * Changing Structure:: Handling changes to the directory structure.
4349 * Special Files:: Handling symbolic links, device special files, etc.
4350 * Unusual File Names:: Handling file names that contain unusual characters.
4351 * Time Stamp Order:: Outputting diffs in time stamp order.
4352 * Ignoring Changes:: Ignoring certain changes while showing others.
4353 * Speedups:: Improving performance.
4356 File: diffutils.info-t, Node: Internationalization, Next: Changing Structure, Up: Shortcomings
4358 18.1.1 Handling Multibyte and Varying-Width Characters
4359 ------------------------------------------------------
4361 `diff', `diff3' and `sdiff' treat each line of input as a string of
4362 unibyte characters. This can mishandle multibyte characters in some
4363 cases. For example, when asked to ignore spaces, `diff' does not
4364 properly ignore a multibyte space character.
4366 Also, `diff' currently assumes that each byte is one column wide,
4367 and this assumption is incorrect in some locales, e.g., locales that
4368 use UTF-8 encoding. This causes problems with the `-y' or
4369 `--side-by-side' option of `diff'.
4371 These problems need to be fixed without unduly affecting the
4372 performance of the utilities in unibyte environments.
4374 The IBM GNU/Linux Technology Center Internationalization Team has
4375 proposed patches to support internationalized `diff'
4376 (http://oss.software.ibm.com/developer/opensource/linux/patches/i18n/diffutils-2.7.2-i18n-0.1.patch.gz).
4377 Unfortunately, these patches are incomplete and are to an older version
4378 of `diff', so more work needs to be done in this area.
4381 File: diffutils.info-t, Node: Changing Structure, Next: Special Files, Prev: Internationalization, Up: Shortcomings
4383 18.1.2 Handling Changes to the Directory Structure
4384 --------------------------------------------------
4386 `diff' and `patch' do not handle some changes to directory structure.
4387 For example, suppose one directory tree contains a directory named `D'
4388 with some subsidiary files, and another contains a file with the same
4389 name `D'. `diff -r' does not output enough information for `patch' to
4390 transform the directory subtree into the file.
4392 There should be a way to specify that a file has been removed without
4393 having to include its entire contents in the patch file. There should
4394 also be a way to tell `patch' that a file was renamed, even if there is
4395 no way for `diff' to generate such information. There should be a way
4396 to tell `patch' that a file's time stamp has changed, even if its
4397 contents have not changed.
4399 These problems can be fixed by extending the `diff' output format to
4400 represent changes in directory structure, and extending `patch' to
4401 understand these extensions.
4404 File: diffutils.info-t, Node: Special Files, Next: Unusual File Names, Prev: Changing Structure, Up: Shortcomings
4406 18.1.3 Files that are Neither Directories Nor Regular Files
4407 -----------------------------------------------------------
4409 Some files are neither directories nor regular files: they are unusual
4410 files like symbolic links, device special files, named pipes, and
4411 sockets. Currently, `diff' treats symbolic links as if they were the
4412 pointed-to files, except that a recursive `diff' reports an error if it
4413 detects infinite loops of symbolic links (e.g., symbolic links to
4414 `..'). `diff' treats other special files like regular files if they
4415 are specified at the top level, but simply reports their presence when
4416 comparing directories. This means that `patch' cannot represent
4417 changes to such files. For example, if you change which file a
4418 symbolic link points to, `diff' outputs the difference between the two
4419 files, instead of the change to the symbolic link.
4421 `diff' should optionally report changes to special files specially,
4422 and `patch' should be extended to understand these extensions.
4425 File: diffutils.info-t, Node: Unusual File Names, Next: Time Stamp Order, Prev: Special Files, Up: Shortcomings
4427 18.1.4 File Names that Contain Unusual Characters
4428 -------------------------------------------------
4430 When a file name contains an unusual character like a newline or white
4431 space, `diff -r' generates a patch that `patch' cannot parse. The
4432 problem is with format of `diff' output, not just with `patch', because
4433 with odd enough file names one can cause `diff' to generate a patch
4434 that is syntactically correct but patches the wrong files. The format
4435 of `diff' output should be extended to handle all possible file names.
4438 File: diffutils.info-t, Node: Time Stamp Order, Next: Ignoring Changes, Prev: Unusual File Names, Up: Shortcomings
4440 18.1.5 Outputting Diffs in Time Stamp Order
4441 -------------------------------------------
4443 Applying `patch' to a multiple-file diff can result in files whose time
4444 stamps are out of order. GNU `patch' has options to restore the time
4445 stamps of the updated files (*note Patching Time Stamps::), but
4446 sometimes it is useful to generate a patch that works even if the
4447 recipient does not have GNU patch, or does not use these options. One
4448 way to do this would be to implement a `diff' option to output diffs in
4452 File: diffutils.info-t, Node: Ignoring Changes, Next: Speedups, Prev: Time Stamp Order, Up: Shortcomings
4454 18.1.6 Ignoring Certain Changes
4455 -------------------------------
4457 It would be nice to have a feature for specifying two strings, one in
4458 FROM-FILE and one in TO-FILE, which should be considered to match.
4459 Thus, if the two strings are `foo' and `bar', then if two lines differ
4460 only in that `foo' in file 1 corresponds to `bar' in file 2, the lines
4461 are treated as identical.
4463 It is not clear how general this feature can or should be, or what
4464 syntax should be used for it.
4466 A partial substitute is to filter one or both files before comparing,
4469 sed 's/foo/bar/g' file1 | diff - file2
4471 However, this outputs the filtered text, not the original.
4474 File: diffutils.info-t, Node: Speedups, Prev: Ignoring Changes, Up: Shortcomings
4476 18.1.7 Improving Performance
4477 ----------------------------
4479 When comparing two large directory structures, one of which was
4480 originally copied from the other with time stamps preserved (e.g., with
4481 `cp -pR'), it would greatly improve performance if an option told
4482 `diff' to assume that two files with the same size and time stamps have
4483 the same content. *Note diff Performance::.
4486 File: diffutils.info-t, Node: Bugs, Prev: Shortcomings, Up: Projects
4491 If you think you have found a bug in GNU `cmp', `diff', `diff3', or
4492 `sdiff', please report it by electronic mail to the GNU utilities bug
4494 (http://mail.gnu.org/mailman/listinfo/bug-gnu-utils)
4495 <bug-gnu-utils@gnu.org>. Please send bug reports for GNU `patch' to
4496 <bug-patch@gnu.org>. Send as precise a description of the problem as
4497 you can, including the output of the `--version' option and sample
4498 input files that produce the bug, if applicable. If you have a
4499 nontrivial fix for the bug, please send it as well. If you have a
4500 patch, please send it too. It may simplify the maintainer's job if the
4501 patch is relative to a recent test release, which you can find in the
4502 directory `ftp://alpha.gnu.org/gnu/diffutils/'.
4505 File: diffutils.info-t, Node: Copying This Manual, Next: Translations, Prev: Projects, Up: Top
4507 Appendix A Copying This Manual
4508 ******************************
4510 Version 1.3, 3 November 2008
4512 Copyright (C) 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
4515 Everyone is permitted to copy and distribute verbatim copies
4516 of this license document, but changing it is not allowed.
4520 The purpose of this License is to make a manual, textbook, or other
4521 functional and useful document "free" in the sense of freedom: to
4522 assure everyone the effective freedom to copy and redistribute it,
4523 with or without modifying it, either commercially or
4524 noncommercially. Secondarily, this License preserves for the
4525 author and publisher a way to get credit for their work, while not
4526 being considered responsible for modifications made by others.
4528 This License is a kind of "copyleft", which means that derivative
4529 works of the document must themselves be free in the same sense.
4530 It complements the GNU General Public License, which is a copyleft
4531 license designed for free software.
4533 We have designed this License in order to use it for manuals for
4534 free software, because free software needs free documentation: a
4535 free program should come with manuals providing the same freedoms
4536 that the software does. But this License is not limited to
4537 software manuals; it can be used for any textual work, regardless
4538 of subject matter or whether it is published as a printed book.
4539 We recommend this License principally for works whose purpose is
4540 instruction or reference.
4542 1. APPLICABILITY AND DEFINITIONS
4544 This License applies to any manual or other work, in any medium,
4545 that contains a notice placed by the copyright holder saying it
4546 can be distributed under the terms of this License. Such a notice
4547 grants a world-wide, royalty-free license, unlimited in duration,
4548 to use that work under the conditions stated herein. The
4549 "Document", below, refers to any such manual or work. Any member
4550 of the public is a licensee, and is addressed as "you". You
4551 accept the license if you copy, modify or distribute the work in a
4552 way requiring permission under copyright law.
4554 A "Modified Version" of the Document means any work containing the
4555 Document or a portion of it, either copied verbatim, or with
4556 modifications and/or translated into another language.
4558 A "Secondary Section" is a named appendix or a front-matter section
4559 of the Document that deals exclusively with the relationship of the
4560 publishers or authors of the Document to the Document's overall
4561 subject (or to related matters) and contains nothing that could
4562 fall directly within that overall subject. (Thus, if the Document
4563 is in part a textbook of mathematics, a Secondary Section may not
4564 explain any mathematics.) The relationship could be a matter of
4565 historical connection with the subject or with related matters, or
4566 of legal, commercial, philosophical, ethical or political position
4569 The "Invariant Sections" are certain Secondary Sections whose
4570 titles are designated, as being those of Invariant Sections, in
4571 the notice that says that the Document is released under this
4572 License. If a section does not fit the above definition of
4573 Secondary then it is not allowed to be designated as Invariant.
4574 The Document may contain zero Invariant Sections. If the Document
4575 does not identify any Invariant Sections then there are none.
4577 The "Cover Texts" are certain short passages of text that are
4578 listed, as Front-Cover Texts or Back-Cover Texts, in the notice
4579 that says that the Document is released under this License. A
4580 Front-Cover Text may be at most 5 words, and a Back-Cover Text may
4581 be at most 25 words.
4583 A "Transparent" copy of the Document means a machine-readable copy,
4584 represented in a format whose specification is available to the
4585 general public, that is suitable for revising the document
4586 straightforwardly with generic text editors or (for images
4587 composed of pixels) generic paint programs or (for drawings) some
4588 widely available drawing editor, and that is suitable for input to
4589 text formatters or for automatic translation to a variety of
4590 formats suitable for input to text formatters. A copy made in an
4591 otherwise Transparent file format whose markup, or absence of
4592 markup, has been arranged to thwart or discourage subsequent
4593 modification by readers is not Transparent. An image format is
4594 not Transparent if used for any substantial amount of text. A
4595 copy that is not "Transparent" is called "Opaque".
4597 Examples of suitable formats for Transparent copies include plain
4598 ASCII without markup, Texinfo input format, LaTeX input format,
4599 SGML or XML using a publicly available DTD, and
4600 standard-conforming simple HTML, PostScript or PDF designed for
4601 human modification. Examples of transparent image formats include
4602 PNG, XCF and JPG. Opaque formats include proprietary formats that
4603 can be read and edited only by proprietary word processors, SGML or
4604 XML for which the DTD and/or processing tools are not generally
4605 available, and the machine-generated HTML, PostScript or PDF
4606 produced by some word processors for output purposes only.
4608 The "Title Page" means, for a printed book, the title page itself,
4609 plus such following pages as are needed to hold, legibly, the
4610 material this License requires to appear in the title page. For
4611 works in formats which do not have any title page as such, "Title
4612 Page" means the text near the most prominent appearance of the
4613 work's title, preceding the beginning of the body of the text.
4615 The "publisher" means any person or entity that distributes copies
4616 of the Document to the public.
4618 A section "Entitled XYZ" means a named subunit of the Document
4619 whose title either is precisely XYZ or contains XYZ in parentheses
4620 following text that translates XYZ in another language. (Here XYZ
4621 stands for a specific section name mentioned below, such as
4622 "Acknowledgements", "Dedications", "Endorsements", or "History".)
4623 To "Preserve the Title" of such a section when you modify the
4624 Document means that it remains a section "Entitled XYZ" according
4627 The Document may include Warranty Disclaimers next to the notice
4628 which states that this License applies to the Document. These
4629 Warranty Disclaimers are considered to be included by reference in
4630 this License, but only as regards disclaiming warranties: any other
4631 implication that these Warranty Disclaimers may have is void and
4632 has no effect on the meaning of this License.
4636 You may copy and distribute the Document in any medium, either
4637 commercially or noncommercially, provided that this License, the
4638 copyright notices, and the license notice saying this License
4639 applies to the Document are reproduced in all copies, and that you
4640 add no other conditions whatsoever to those of this License. You
4641 may not use technical measures to obstruct or control the reading
4642 or further copying of the copies you make or distribute. However,
4643 you may accept compensation in exchange for copies. If you
4644 distribute a large enough number of copies you must also follow
4645 the conditions in section 3.
4647 You may also lend copies, under the same conditions stated above,
4648 and you may publicly display copies.
4650 3. COPYING IN QUANTITY
4652 If you publish printed copies (or copies in media that commonly
4653 have printed covers) of the Document, numbering more than 100, and
4654 the Document's license notice requires Cover Texts, you must
4655 enclose the copies in covers that carry, clearly and legibly, all
4656 these Cover Texts: Front-Cover Texts on the front cover, and
4657 Back-Cover Texts on the back cover. Both covers must also clearly
4658 and legibly identify you as the publisher of these copies. The
4659 front cover must present the full title with all words of the
4660 title equally prominent and visible. You may add other material
4661 on the covers in addition. Copying with changes limited to the
4662 covers, as long as they preserve the title of the Document and
4663 satisfy these conditions, can be treated as verbatim copying in
4666 If the required texts for either cover are too voluminous to fit
4667 legibly, you should put the first ones listed (as many as fit
4668 reasonably) on the actual cover, and continue the rest onto
4671 If you publish or distribute Opaque copies of the Document
4672 numbering more than 100, you must either include a
4673 machine-readable Transparent copy along with each Opaque copy, or
4674 state in or with each Opaque copy a computer-network location from
4675 which the general network-using public has access to download
4676 using public-standard network protocols a complete Transparent
4677 copy of the Document, free of added material. If you use the
4678 latter option, you must take reasonably prudent steps, when you
4679 begin distribution of Opaque copies in quantity, to ensure that
4680 this Transparent copy will remain thus accessible at the stated
4681 location until at least one year after the last time you
4682 distribute an Opaque copy (directly or through your agents or
4683 retailers) of that edition to the public.
4685 It is requested, but not required, that you contact the authors of
4686 the Document well before redistributing any large number of
4687 copies, to give them a chance to provide you with an updated
4688 version of the Document.
4692 You may copy and distribute a Modified Version of the Document
4693 under the conditions of sections 2 and 3 above, provided that you
4694 release the Modified Version under precisely this License, with
4695 the Modified Version filling the role of the Document, thus
4696 licensing distribution and modification of the Modified Version to
4697 whoever possesses a copy of it. In addition, you must do these
4698 things in the Modified Version:
4700 A. Use in the Title Page (and on the covers, if any) a title
4701 distinct from that of the Document, and from those of
4702 previous versions (which should, if there were any, be listed
4703 in the History section of the Document). You may use the
4704 same title as a previous version if the original publisher of
4705 that version gives permission.
4707 B. List on the Title Page, as authors, one or more persons or
4708 entities responsible for authorship of the modifications in
4709 the Modified Version, together with at least five of the
4710 principal authors of the Document (all of its principal
4711 authors, if it has fewer than five), unless they release you
4712 from this requirement.
4714 C. State on the Title page the name of the publisher of the
4715 Modified Version, as the publisher.
4717 D. Preserve all the copyright notices of the Document.
4719 E. Add an appropriate copyright notice for your modifications
4720 adjacent to the other copyright notices.
4722 F. Include, immediately after the copyright notices, a license
4723 notice giving the public permission to use the Modified
4724 Version under the terms of this License, in the form shown in
4727 G. Preserve in that license notice the full lists of Invariant
4728 Sections and required Cover Texts given in the Document's
4731 H. Include an unaltered copy of this License.
4733 I. Preserve the section Entitled "History", Preserve its Title,
4734 and add to it an item stating at least the title, year, new
4735 authors, and publisher of the Modified Version as given on
4736 the Title Page. If there is no section Entitled "History" in
4737 the Document, create one stating the title, year, authors,
4738 and publisher of the Document as given on its Title Page,
4739 then add an item describing the Modified Version as stated in
4740 the previous sentence.
4742 J. Preserve the network location, if any, given in the Document
4743 for public access to a Transparent copy of the Document, and
4744 likewise the network locations given in the Document for
4745 previous versions it was based on. These may be placed in
4746 the "History" section. You may omit a network location for a
4747 work that was published at least four years before the
4748 Document itself, or if the original publisher of the version
4749 it refers to gives permission.
4751 K. For any section Entitled "Acknowledgements" or "Dedications",
4752 Preserve the Title of the section, and preserve in the
4753 section all the substance and tone of each of the contributor
4754 acknowledgements and/or dedications given therein.
4756 L. Preserve all the Invariant Sections of the Document,
4757 unaltered in their text and in their titles. Section numbers
4758 or the equivalent are not considered part of the section
4761 M. Delete any section Entitled "Endorsements". Such a section
4762 may not be included in the Modified Version.
4764 N. Do not retitle any existing section to be Entitled
4765 "Endorsements" or to conflict in title with any Invariant
4768 O. Preserve any Warranty Disclaimers.
4770 If the Modified Version includes new front-matter sections or
4771 appendices that qualify as Secondary Sections and contain no
4772 material copied from the Document, you may at your option
4773 designate some or all of these sections as invariant. To do this,
4774 add their titles to the list of Invariant Sections in the Modified
4775 Version's license notice. These titles must be distinct from any
4776 other section titles.
4778 You may add a section Entitled "Endorsements", provided it contains
4779 nothing but endorsements of your Modified Version by various
4780 parties--for example, statements of peer review or that the text
4781 has been approved by an organization as the authoritative
4782 definition of a standard.
4784 You may add a passage of up to five words as a Front-Cover Text,
4785 and a passage of up to 25 words as a Back-Cover Text, to the end
4786 of the list of Cover Texts in the Modified Version. Only one
4787 passage of Front-Cover Text and one of Back-Cover Text may be
4788 added by (or through arrangements made by) any one entity. If the
4789 Document already includes a cover text for the same cover,
4790 previously added by you or by arrangement made by the same entity
4791 you are acting on behalf of, you may not add another; but you may
4792 replace the old one, on explicit permission from the previous
4793 publisher that added the old one.
4795 The author(s) and publisher(s) of the Document do not by this
4796 License give permission to use their names for publicity for or to
4797 assert or imply endorsement of any Modified Version.
4799 5. COMBINING DOCUMENTS
4801 You may combine the Document with other documents released under
4802 this License, under the terms defined in section 4 above for
4803 modified versions, provided that you include in the combination
4804 all of the Invariant Sections of all of the original documents,
4805 unmodified, and list them all as Invariant Sections of your
4806 combined work in its license notice, and that you preserve all
4807 their Warranty Disclaimers.
4809 The combined work need only contain one copy of this License, and
4810 multiple identical Invariant Sections may be replaced with a single
4811 copy. If there are multiple Invariant Sections with the same name
4812 but different contents, make the title of each such section unique
4813 by adding at the end of it, in parentheses, the name of the
4814 original author or publisher of that section if known, or else a
4815 unique number. Make the same adjustment to the section titles in
4816 the list of Invariant Sections in the license notice of the
4819 In the combination, you must combine any sections Entitled
4820 "History" in the various original documents, forming one section
4821 Entitled "History"; likewise combine any sections Entitled
4822 "Acknowledgements", and any sections Entitled "Dedications". You
4823 must delete all sections Entitled "Endorsements."
4825 6. COLLECTIONS OF DOCUMENTS
4827 You may make a collection consisting of the Document and other
4828 documents released under this License, and replace the individual
4829 copies of this License in the various documents with a single copy
4830 that is included in the collection, provided that you follow the
4831 rules of this License for verbatim copying of each of the
4832 documents in all other respects.
4834 You may extract a single document from such a collection, and
4835 distribute it individually under this License, provided you insert
4836 a copy of this License into the extracted document, and follow
4837 this License in all other respects regarding verbatim copying of
4840 7. AGGREGATION WITH INDEPENDENT WORKS
4842 A compilation of the Document or its derivatives with other
4843 separate and independent documents or works, in or on a volume of
4844 a storage or distribution medium, is called an "aggregate" if the
4845 copyright resulting from the compilation is not used to limit the
4846 legal rights of the compilation's users beyond what the individual
4847 works permit. When the Document is included in an aggregate, this
4848 License does not apply to the other works in the aggregate which
4849 are not themselves derivative works of the Document.
4851 If the Cover Text requirement of section 3 is applicable to these
4852 copies of the Document, then if the Document is less than one half
4853 of the entire aggregate, the Document's Cover Texts may be placed
4854 on covers that bracket the Document within the aggregate, or the
4855 electronic equivalent of covers if the Document is in electronic
4856 form. Otherwise they must appear on printed covers that bracket
4857 the whole aggregate.
4861 Translation is considered a kind of modification, so you may
4862 distribute translations of the Document under the terms of section
4863 4. Replacing Invariant Sections with translations requires special
4864 permission from their copyright holders, but you may include
4865 translations of some or all Invariant Sections in addition to the
4866 original versions of these Invariant Sections. You may include a
4867 translation of this License, and all the license notices in the
4868 Document, and any Warranty Disclaimers, provided that you also
4869 include the original English version of this License and the
4870 original versions of those notices and disclaimers. In case of a
4871 disagreement between the translation and the original version of
4872 this License or a notice or disclaimer, the original version will
4875 If a section in the Document is Entitled "Acknowledgements",
4876 "Dedications", or "History", the requirement (section 4) to
4877 Preserve its Title (section 1) will typically require changing the
4882 You may not copy, modify, sublicense, or distribute the Document
4883 except as expressly provided under this License. Any attempt
4884 otherwise to copy, modify, sublicense, or distribute it is void,
4885 and will automatically terminate your rights under this License.
4887 However, if you cease all violation of this License, then your
4888 license from a particular copyright holder is reinstated (a)
4889 provisionally, unless and until the copyright holder explicitly
4890 and finally terminates your license, and (b) permanently, if the
4891 copyright holder fails to notify you of the violation by some
4892 reasonable means prior to 60 days after the cessation.
4894 Moreover, your license from a particular copyright holder is
4895 reinstated permanently if the copyright holder notifies you of the
4896 violation by some reasonable means, this is the first time you have
4897 received notice of violation of this License (for any work) from
4898 that copyright holder, and you cure the violation prior to 30 days
4899 after your receipt of the notice.
4901 Termination of your rights under this section does not terminate
4902 the licenses of parties who have received copies or rights from
4903 you under this License. If your rights have been terminated and
4904 not permanently reinstated, receipt of a copy of some or all of
4905 the same material does not give you any rights to use it.
4907 10. FUTURE REVISIONS OF THIS LICENSE
4909 The Free Software Foundation may publish new, revised versions of
4910 the GNU Free Documentation License from time to time. Such new
4911 versions will be similar in spirit to the present version, but may
4912 differ in detail to address new problems or concerns. See
4913 `http://www.gnu.org/copyleft/'.
4915 Each version of the License is given a distinguishing version
4916 number. If the Document specifies that a particular numbered
4917 version of this License "or any later version" applies to it, you
4918 have the option of following the terms and conditions either of
4919 that specified version or of any later version that has been
4920 published (not as a draft) by the Free Software Foundation. If
4921 the Document does not specify a version number of this License,
4922 you may choose any version ever published (not as a draft) by the
4923 Free Software Foundation. If the Document specifies that a proxy
4924 can decide which future versions of this License can be used, that
4925 proxy's public statement of acceptance of a version permanently
4926 authorizes you to choose that version for the Document.
4930 "Massive Multiauthor Collaboration Site" (or "MMC Site") means any
4931 World Wide Web server that publishes copyrightable works and also
4932 provides prominent facilities for anybody to edit those works. A
4933 public wiki that anybody can edit is an example of such a server.
4934 A "Massive Multiauthor Collaboration" (or "MMC") contained in the
4935 site means any set of copyrightable works thus published on the MMC
4938 "CC-BY-SA" means the Creative Commons Attribution-Share Alike 3.0
4939 license published by Creative Commons Corporation, a not-for-profit
4940 corporation with a principal place of business in San Francisco,
4941 California, as well as future copyleft versions of that license
4942 published by that same organization.
4944 "Incorporate" means to publish or republish a Document, in whole or
4945 in part, as part of another Document.
4947 An MMC is "eligible for relicensing" if it is licensed under this
4948 License, and if all works that were first published under this
4949 License somewhere other than this MMC, and subsequently
4950 incorporated in whole or in part into the MMC, (1) had no cover
4951 texts or invariant sections, and (2) were thus incorporated prior
4952 to November 1, 2008.
4954 The operator of an MMC Site may republish an MMC contained in the
4955 site under CC-BY-SA on the same site at any time before August 1,
4956 2009, provided the MMC is eligible for relicensing.
4959 ADDENDUM: How to use this License for your documents
4960 ====================================================
4962 To use this License in a document you have written, include a copy of
4963 the License in the document and put the following copyright and license
4964 notices just after the title page:
4966 Copyright (C) YEAR YOUR NAME.
4967 Permission is granted to copy, distribute and/or modify this document
4968 under the terms of the GNU Free Documentation License, Version 1.3
4969 or any later version published by the Free Software Foundation;
4970 with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
4971 Texts. A copy of the license is included in the section entitled ``GNU
4972 Free Documentation License''.
4974 If you have Invariant Sections, Front-Cover Texts and Back-Cover
4975 Texts, replace the "with...Texts." line with this:
4977 with the Invariant Sections being LIST THEIR TITLES, with
4978 the Front-Cover Texts being LIST, and with the Back-Cover Texts
4981 If you have Invariant Sections without Cover Texts, or some other
4982 combination of the three, merge those two alternatives to suit the
4985 If your document contains nontrivial examples of program code, we
4986 recommend releasing these examples in parallel under your choice of
4987 free software license, such as the GNU General Public License, to
4988 permit their use in free software.
4991 File: diffutils.info-t, Node: Translations, Next: Index, Prev: Copying This Manual, Up: Top
4993 Appendix B Translations of This Manual
4994 **************************************
4996 Nishio Futoshi of the GNUjdoc project has prepared a Japanese
4997 translation of this manual. Its most recent version can be found at
4998 `http://openlab.ring.gr.jp/gnujdoc/cvsweb/cvsweb.cgi/gnujdoc/'.
5001 File: diffutils.info-t, Node: Index, Prev: Translations, Up: Top
5009 * ! output format: Context. (line 6)
5010 * +- output format: Unified Format. (line 6)
5011 * < output format: Normal. (line 6)
5012 * <<<<<<< for marking conflicts: Marking Conflicts. (line 6)
5013 * _POSIX2_VERSION: Standards conformance.
5015 * aligning tab stops: Tabs. (line 6)
5016 * alternate file names: Alternate Names. (line 6)
5017 * backup file names: Backup Names. (line 6)
5018 * backup file strategy: Backups. (line 6)
5019 * binary file diff: Binary. (line 6)
5020 * blank and tab difference suppression: White Space. (line 6)
5021 * blank line difference suppression: Blank Lines. (line 6)
5022 * brief difference reports: Brief. (line 6)
5023 * bug reports: Bugs. (line 6)
5024 * C function headings: C Function Headings. (line 6)
5025 * C if-then-else output format: If-then-else. (line 6)
5026 * case difference suppression: Case Folding. (line 6)
5027 * ClearCase: Revision Control. (line 6)
5028 * cmp invocation: Invoking cmp. (line 6)
5029 * cmp options: cmp Options. (line 6)
5030 * columnar output: Side by Side. (line 6)
5031 * common mistakes with patches: Avoiding Common Mistakes.
5033 * comparing three files: Comparing Three Files.
5035 * conflict: diff3 Merging. (line 26)
5036 * conflict marking: Marking Conflicts. (line 6)
5037 * context output format: Context. (line 6)
5038 * creating files: Creating and Removing.
5040 * diagnostics from patch: patch Messages. (line 6)
5041 * diff invocation: Invoking diff. (line 6)
5042 * diff merging: Interactive Merging. (line 6)
5043 * diff options: diff Options. (line 6)
5044 * diff sample input: Sample diff Input. (line 6)
5045 * diff3 hunks: diff3 Hunks. (line 6)
5046 * diff3 invocation: Invoking diff3. (line 6)
5047 * diff3 options: diff3 Options. (line 6)
5048 * diff3 sample input: Sample diff3 Input. (line 6)
5049 * directories and patch: patch Directories. (line 6)
5050 * directory structure changes: Changing Structure. (line 6)
5051 * dry runs for patch: Dry Runs. (line 6)
5052 * ed script output format: ed Scripts. (line 6)
5053 * EDITOR: Merge Commands. (line 50)
5054 * empty files, removing: Creating and Removing.
5056 * exabyte, definition of: cmp Options. (line 109)
5057 * exbibyte, definition of: cmp Options. (line 113)
5058 * file name alternates: Alternate Names. (line 6)
5059 * file names with unusual characters: Unusual File Names. (line 6)
5060 * format of diff output: Output Formats. (line 6)
5061 * format of diff3 output: Comparing Three Files.
5063 * formats for if-then-else line groups: Line Group Formats. (line 6)
5064 * forward ed script output format: Forward ed. (line 6)
5065 * full lines: Incomplete Lines. (line 6)
5066 * function headings, C: C Function Headings. (line 6)
5067 * fuzz factor when patching: Inexact. (line 6)
5068 * gibibyte, definition of: cmp Options. (line 92)
5069 * gigabyte, definition of: cmp Options. (line 88)
5070 * headings: Sections. (line 6)
5071 * hunks: Hunks. (line 6)
5072 * hunks for diff3: diff3 Hunks. (line 6)
5073 * if-then-else output format: If-then-else. (line 6)
5074 * ifdef output format: If-then-else. (line 6)
5075 * imperfect patch application: Imperfect. (line 6)
5076 * incomplete line merging: Merging Incomplete Lines.
5078 * incomplete lines: Incomplete Lines. (line 6)
5079 * inexact patches: Inexact. (line 6)
5080 * inhibit messages from patch: More or Fewer Messages.
5082 * interactive merging: Interactive Merging. (line 6)
5083 * introduction: Comparison. (line 6)
5084 * intuiting file names from patches: Multiple Patches. (line 6)
5085 * invoking cmp: Invoking cmp. (line 6)
5086 * invoking diff: Invoking diff. (line 6)
5087 * invoking diff3: Invoking diff3. (line 6)
5088 * invoking patch: Invoking patch. (line 6)
5089 * invoking sdiff: Invoking sdiff. (line 6)
5090 * keyboard input to patch: patch and Keyboard Input.
5092 * kibibyte, definition of: cmp Options. (line 76)
5093 * kilobyte, definition of: cmp Options. (line 71)
5094 * LC_COLLATE: Comparing Directories.
5096 * LC_NUMERIC: Line Group Formats. (line 144)
5097 * LC_TIME: Detailed Context. (line 12)
5098 * line formats: Line Formats. (line 6)
5099 * line group formats: Line Group Formats. (line 6)
5100 * mebibyte, definition of: cmp Options. (line 85)
5101 * megabyte, definition of: cmp Options. (line 81)
5102 * merge commands: Merge Commands. (line 6)
5103 * merged diff3 format: Bypassing ed. (line 6)
5104 * merged output format: If-then-else. (line 6)
5105 * merging from a common ancestor: diff3 Merging. (line 6)
5106 * merging interactively: Merge Commands. (line 6)
5107 * messages from patch: patch Messages. (line 6)
5108 * multibyte characters: Internationalization.
5110 * multiple patches: Multiple Patches. (line 6)
5111 * newline treatment by diff: Incomplete Lines. (line 6)
5112 * normal output format: Normal. (line 6)
5113 * options for cmp: cmp Options. (line 6)
5114 * options for diff: diff Options. (line 6)
5115 * options for diff3: diff3 Options. (line 6)
5116 * options for patch: patch Options. (line 6)
5117 * options for sdiff: sdiff Options. (line 6)
5118 * output formats: Output Formats. (line 6)
5119 * overlap: diff3 Merging. (line 26)
5120 * overlapping change, selection of: Which Changes. (line 6)
5121 * overview of diff and patch: Overview. (line 6)
5122 * paginating diff output: Pagination. (line 6)
5123 * patch consumer tips: Tips for Patch Consumers.
5125 * patch input format: patch Input. (line 6)
5126 * patch invocation: Invoking patch. (line 6)
5127 * patch messages and questions: patch Messages. (line 6)
5128 * patch options: patch Options. (line 6)
5129 * patch producer tips: Tips for Patch Producers.
5131 * patch, common mistakes: Avoiding Common Mistakes.
5133 * PATCH_GET: Revision Control. (line 13)
5134 * PATCH_VERSION_CONTROL: Backup Names. (line 21)
5135 * patches, shrinking: Generating Smaller Patches.
5137 * patching directories: patch Directories. (line 6)
5138 * pebibyte, definition of: cmp Options. (line 106)
5139 * performance of diff: diff Performance. (line 6)
5140 * petabyte, definition of: cmp Options. (line 102)
5141 * POSIX <1>: Standards conformance.
5143 * POSIX: patch and POSIX. (line 6)
5144 * POSIXLY_CORRECT <1>: Standards conformance.
5146 * POSIXLY_CORRECT: patch and POSIX. (line 6)
5147 * projects for directories: Shortcomings. (line 6)
5148 * quoting style: patch Quoting Style. (line 6)
5149 * QUOTING_STYLE: patch Quoting Style. (line 30)
5150 * RCS: Revision Control. (line 6)
5151 * RCS script output format: RCS. (line 6)
5152 * regular expression matching headings: Specified Headings. (line 6)
5153 * regular expression suppression: Specified Lines. (line 6)
5154 * reject file names: Reject Names. (line 6)
5155 * removing empty files: Creating and Removing.
5157 * reporting bugs: Bugs. (line 6)
5158 * reversed patches: Reversed Patches. (line 6)
5159 * revision control: Revision Control. (line 6)
5160 * sample input for diff: Sample diff Input. (line 6)
5161 * sample input for diff3: Sample diff3 Input. (line 6)
5162 * SCCS: Revision Control. (line 6)
5163 * script output formats: Scripts. (line 6)
5164 * sdiff invocation: Invoking sdiff. (line 6)
5165 * sdiff options: sdiff Options. (line 6)
5166 * sdiff output format: sdiff Option Summary.
5168 * section headings: Sections. (line 6)
5169 * side by side: Side by Side. (line 6)
5170 * side by side format: Side by Side Format. (line 6)
5171 * SIMPLE_BACKUP_SUFFIX: Backup Names. (line 12)
5172 * special files: Special Files. (line 6)
5173 * specified headings: Specified Headings. (line 6)
5174 * summarizing which files differ: Brief. (line 6)
5175 * System V diff3 compatibility: Saving the Changed File.
5177 * tab and blank difference suppression: White Space. (line 6)
5178 * tab stop alignment: Tabs. (line 6)
5179 * tebibyte, definition of: cmp Options. (line 99)
5180 * terabyte, definition of: cmp Options. (line 95)
5181 * testing patch: Dry Runs. (line 6)
5182 * text versus binary diff: Binary. (line 6)
5183 * time stamp format, context diffs: Detailed Context. (line 12)
5184 * time stamp format, unified diffs: Detailed Unified. (line 12)
5185 * time stamps on patched files: Patching Time Stamps.
5187 * traditional patch: patch and Tradition. (line 6)
5188 * trailing blanks: Trailing Blanks. (line 6)
5189 * two-column output: Side by Side. (line 6)
5190 * unified output format: Unified Format. (line 6)
5191 * unmerged change: Which Changes. (line 6)
5192 * varying-width characters: Internationalization.
5194 * verbose messages from patch: More or Fewer Messages.
5196 * version control: Revision Control. (line 6)
5197 * VERSION_CONTROL <1>: Backup Names. (line 21)
5198 * VERSION_CONTROL: Revision Control. (line 22)
5199 * white space in patches: Changed White Space. (line 6)
5200 * yottabyte, definition of: cmp Options. (line 124)
5201 * zettabyte, definition of: cmp Options. (line 116)
5207 Node: Overview
\7f3648
5208 Node: Comparison
\7f7279
5210 Node: White Space
\7f11428
5211 Node: Blank Lines
\7f13269
5212 Node: Specified Lines
\7f14263
5213 Node: Case Folding
\7f15391
5215 Node: Binary
\7f17135
5216 Node: Output Formats
\7f21222
5217 Node: Sample diff Input
\7f21949
5218 Node: Context
\7f23450
5219 Node: Context Format
\7f25029
5220 Node: Example Context
\7f25823
5221 Node: Less Context
\7f27332
5222 Node: Detailed Context
\7f28523
5223 Node: Unified Format
\7f30723
5224 Node: Example Unified
\7f31522
5225 Node: Detailed Unified
\7f32562
5226 Node: Sections
\7f34207
5227 Node: Specified Headings
\7f34968
5228 Node: C Function Headings
\7f36521
5229 Node: Alternate Names
\7f37368
5230 Node: Side by Side
\7f38284
5231 Node: Side by Side Format
\7f40436
5232 Node: Example Side by Side
\7f41339
5233 Node: Normal
\7f42681
5234 Node: Example Normal
\7f43683
5235 Node: Detailed Normal
\7f44421
5236 Node: Scripts
\7f46162
5237 Node: ed Scripts
\7f46569
5238 Node: Example ed
\7f47777
5239 Node: Detailed ed
\7f48229
5240 Node: Forward ed
\7f49990
5242 Node: If-then-else
\7f51985
5243 Node: Line Group Formats
\7f53665
5244 Node: Line Formats
\7f59543
5245 Node: Example If-then-else
\7f62815
5246 Node: Detailed If-then-else
\7f63896
5247 Node: Incomplete Lines
\7f65782
5248 Node: Comparing Directories
\7f67422
5249 Node: Adjusting Output
\7f71856
5251 Node: Trailing Blanks
\7f73981
5252 Node: Pagination
\7f75209
5253 Node: diff Performance
\7f75679
5254 Node: Comparing Three Files
\7f78768
5255 Node: Sample diff3 Input
\7f79648
5256 Node: Example diff3 Normal
\7f80598
5257 Node: Detailed diff3 Normal
\7f81660
5258 Node: diff3 Hunks
\7f83450
5259 Node: diff3 Merging
\7f84719
5260 Node: Which Changes
\7f86965
5261 Node: Marking Conflicts
\7f88367
5262 Node: Bypassing ed
\7f90825
5263 Node: Merging Incomplete Lines
\7f92170
5264 Node: Saving the Changed File
\7f92898
5265 Node: Interactive Merging
\7f93516
5266 Node: sdiff Option Summary
\7f94227
5267 Node: Merge Commands
\7f95432
5268 Node: Merging with patch
\7f96723
5269 Node: patch Input
\7f99097
5270 Node: Revision Control
\7f99781
5271 Node: Imperfect
\7f100953
5272 Node: Changed White Space
\7f102103
5273 Node: Reversed Patches
\7f102902
5274 Node: Inexact
\7f104368
5275 Node: Dry Runs
\7f107928
5276 Node: Creating and Removing
\7f108794
5277 Node: Patching Time Stamps
\7f109845
5278 Node: Multiple Patches
\7f112046
5279 Node: patch Directories
\7f114711
5280 Node: Backups
\7f116338
5281 Node: Backup Names
\7f117405
5282 Ref: Backup Names-Footnote-1
\7f120374
5283 Node: Reject Names
\7f120501
5284 Node: patch Messages
\7f121092
5285 Node: More or Fewer Messages
\7f122154
5286 Node: patch and Keyboard Input
\7f122787
5287 Node: patch Quoting Style
\7f123818
5288 Node: patch and POSIX
\7f124970
5289 Node: patch and Tradition
\7f125812
5290 Node: Making Patches
\7f129270
5291 Node: Tips for Patch Producers
\7f130098
5292 Node: Tips for Patch Consumers
\7f131356
5293 Node: Avoiding Common Mistakes
\7f131995
5294 Node: Generating Smaller Patches
\7f134522
5295 Node: Invoking cmp
\7f136285
5296 Node: cmp Options
\7f137710
5297 Node: Invoking diff
\7f141373
5298 Node: diff Options
\7f143231
5299 Node: Invoking diff3
\7f151877
5300 Node: diff3 Options
\7f152517
5301 Node: Invoking patch
\7f155552
5302 Node: patch Options
\7f156762
5303 Node: Invoking sdiff
\7f161991
5304 Node: sdiff Options
\7f163136
5305 Node: Standards conformance
\7f166109
5306 Node: Projects
\7f167857
5307 Node: Shortcomings
\7f168570
5308 Node: Internationalization
\7f169674
5309 Node: Changing Structure
\7f170842
5310 Node: Special Files
\7f171948
5311 Node: Unusual File Names
\7f173062
5312 Node: Time Stamp Order
\7f173703
5313 Node: Ignoring Changes
\7f174348
5314 Node: Speedups
\7f175120
5316 Node: Copying This Manual
\7f176441
5317 Node: Translations
\7f201582
5318 Node: Index
\7f201956