1 LESS(1) General Commands Manual LESS(1)
6 less - opposite of more
12 \e[1mless --version
\e[0m
13 \e[1mless [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
\e[0m
14 \e[1m[-b
\e[4m
\e[22mspace
\e[24m
\e[1m] [-h
\e[4m
\e[22mlines
\e[24m
\e[1m] [-j
\e[4m
\e[22mline
\e[24m
\e[1m] [-k
\e[4m
\e[22mkeyfile
\e[24m
\e[1m]
\e[0m
15 \e[1m[-{oO}
\e[4m
\e[22mlogfile
\e[24m
\e[1m] [-p
\e[4m
\e[22mpattern
\e[24m
\e[1m] [-P
\e[4m
\e[22mprompt
\e[24m
\e[1m] [-t
\e[4m
\e[22mtag
\e[24m
\e[1m]
\e[0m
16 \e[1m[-T
\e[4m
\e[22mtagsfile
\e[24m
\e[1m] [-x
\e[4m
\e[22mtab
\e[24m
\e[1m,...] [-y
\e[4m
\e[22mlines
\e[24m
\e[1m] [-[z]
\e[4m
\e[22mlines
\e[24m
\e[1m]
\e[0m
17 \e[1m[-#
\e[4m
\e[22mshift
\e[24m
\e[1m] [+[+]
\e[4m
\e[22mcmd
\e[24m
\e[1m] [--] [
\e[4m
\e[22mfilename
\e[24m
\e[1m]...
\e[0m
18 (See the OPTIONS section for alternate option syntax with long option
23 \e[4mLess
\e[24m is a program similar to
\e[4mmore
\e[24m (1), but which allows backward move-
24 ment in the file as well as forward movement. Also,
\e[4mless
\e[24m does not have
25 to read the entire input file before starting, so with large input
26 files it starts up faster than text editors like
\e[4mvi
\e[24m (1).
\e[4mLess
\e[24m uses
27 termcap (or terminfo on some systems), so it can run on a variety of
28 terminals. There is even limited support for hardcopy terminals. (On
29 a hardcopy terminal, lines which should be printed at the top of the
30 screen are prefixed with a caret.)
32 Commands are based on both
\e[4mmore
\e[24m and
\e[4mvi.
\e[24m Commands may be preceded by a
33 decimal number, called N in the descriptions below. The number is used
34 by some commands, as indicated.
38 In the following descriptions, ^X means control-X. ESC stands for the
39 ESCAPE key; for example ESC-v means the two character sequence
42 h or H Help: display a summary of these commands. If you forget all
43 the other commands, remember this one.
45 SPACE or ^V or f or ^F
46 Scroll forward N lines, default one window (see option -z
47 below). If N is more than the screen size, only the final
48 screenful is displayed. Warning: some systems use ^V as a spe-
49 cial literalization character.
51 z Like SPACE, but if N is specified, it becomes the new window
55 Like SPACE, but scrolls a full screenful, even if it reaches
56 end-of-file in the process.
58 ENTER or RETURN or ^N or e or ^E or j or ^J
59 Scroll forward N lines, default 1. The entire N lines are dis-
60 played, even if N is more than the screen size.
63 Scroll forward N lines, default one half of the screen size. If
64 N is specified, it becomes the new default for subsequent d and
68 Scroll backward N lines, default one window (see option -z
69 below). If N is more than the screen size, only the final
70 screenful is displayed.
72 w Like ESC-v, but if N is specified, it becomes the new window
75 y or ^Y or ^P or k or ^K
76 Scroll backward N lines, default 1. The entire N lines are dis-
77 played, even if N is more than the screen size. Warning: some
78 systems use ^Y as a special job control character.
81 Scroll backward N lines, default one half of the screen size.
82 If N is specified, it becomes the new default for subsequent d
85 J Like j, but continues to scroll beyond the end of the file.
87 K or Y Like k, but continues to scroll beyond the beginning of the
91 Scroll horizontally right N characters, default half the screen
92 width (see the -# option). If a number N is specified, it
93 becomes the default for future RIGHTARROW and LEFTARROW com-
94 mands. While the text is scrolled, it acts as though the -S
95 option (chop lines) were in effect.
98 Scroll horizontally left N characters, default half the screen
99 width (see the -# option). If a number N is specified, it
100 becomes the default for future RIGHTARROW and LEFTARROW com-
104 Scroll horizontally right to show the end of the longest dis-
108 Scroll horizontally left back to the first column.
113 R Repaint the screen, discarding any buffered input. Useful if
114 the file is changing while it is being viewed.
116 F Scroll forward, and keep trying to read when the end of file is
117 reached. Normally this command would be used when already at
118 the end of the file. It is a way to monitor the tail of a file
119 which is growing while it is being viewed. (The behavior is
120 similar to the "tail -f" command.)
122 ESC-F Like F, but as soon as a line is found which matches the last
123 search pattern, the terminal bell is rung and forward scrolling
127 Go to line N in the file, default 1 (beginning of file). (Warn-
128 ing: this may be slow if N is large.)
131 Go to line N in the file, default the end of the file. (Warn-
132 ing: this may be slow if N is large, or if N is not specified
133 and standard input, rather than a file, is being read.)
135 ESC-G Same as G, except if no number N is specified and the input is
136 standard input, goes to the last line which is currently
139 p or % Go to a position N percent into the file. N should be between 0
140 and 100, and may contain a decimal point.
142 P Go to the line containing byte offset N in the file.
144 { If a left curly bracket appears in the top line displayed on the
145 screen, the { command will go to the matching right curly
146 bracket. The matching right curly bracket is positioned on the
147 bottom line of the screen. If there is more than one left curly
148 bracket on the top line, a number N may be used to specify the
149 N-th bracket on the line.
151 } If a right curly bracket appears in the bottom line displayed on
152 the screen, the } command will go to the matching left curly
153 bracket. The matching left curly bracket is positioned on the
154 top line of the screen. If there is more than one right curly
155 bracket on the top line, a number N may be used to specify the
156 N-th bracket on the line.
158 ( Like {, but applies to parentheses rather than curly brackets.
160 ) Like }, but applies to parentheses rather than curly brackets.
162 [ Like {, but applies to square brackets rather than curly brack-
165 ] Like }, but applies to square brackets rather than curly brack-
168 ESC-^F Followed by two characters, acts like {, but uses the two char-
169 acters as open and close brackets, respectively. For example,
170 "ESC ^F < >" could be used to go forward to the > which matches
171 the < in the top displayed line.
173 ESC-^B Followed by two characters, acts like }, but uses the two char-
174 acters as open and close brackets, respectively. For example,
175 "ESC ^B < >" could be used to go backward to the < which matches
176 the > in the bottom displayed line.
178 m Followed by any lowercase letter, marks the current position
181 ' (Single quote.) Followed by any lowercase letter, returns to
182 the position which was previously marked with that letter. Fol-
183 lowed by another single quote, returns to the position at which
184 the last "large" movement command was executed. Followed by a ^
185 or $, jumps to the beginning or end of the file respectively.
186 Marks are preserved when a new file is examined, so the ' com-
187 mand can be used to switch between input files.
189 ^X^X Same as single quote.
192 Search forward in the file for the N-th line containing the pat-
193 tern. N defaults to 1. The pattern is a regular expression, as
194 recognized by the regular expression library supplied by your
195 system. The search starts at the first line displayed (but see
196 the -a and -j options, which change this).
198 Certain characters are special if entered at the beginning of
199 the pattern; they modify the type of search rather than become
203 Search for lines which do NOT match the pattern.
206 Search multiple files. That is, if the search reaches
207 the END of the current file without finding a match, the
208 search continues in the next file in the command line
212 Begin the search at the first line of the FIRST file in
213 the command line list, regardless of what is currently
214 displayed on the screen or the settings of the -a or -j
217 ^K Highlight any text which matches the pattern on the cur-
218 rent screen, but don't move to the first match (KEEP cur-
221 ^R Don't interpret regular expression metacharacters; that
222 is, do a simple textual comparison.
225 Search backward in the file for the N-th line containing the
226 pattern. The search starts at the last line displayed (but see
227 the -a and -j options, which change this).
229 Certain characters are special as in the / command:
232 Search for lines which do NOT match the pattern.
235 Search multiple files. That is, if the search reaches
236 the beginning of the current file without finding a
237 match, the search continues in the previous file in the
241 Begin the search at the last line of the last file in the
242 command line list, regardless of what is currently dis-
243 played on the screen or the settings of the -a or -j
246 ^K As in forward searches.
248 ^R As in forward searches.
256 n Repeat previous search, for N-th line containing the last pat-
257 tern. If the previous search was modified by ^N, the search is
258 made for the N-th line NOT containing the pattern. If the pre-
259 vious search was modified by ^E, the search continues in the
260 next (or previous) file if not satisfied in the current file.
261 If the previous search was modified by ^R, the search is done
262 without using regular expressions. There is no effect if the
263 previous search was modified by ^F or ^K.
265 N Repeat previous search, but in the reverse direction.
267 ESC-n Repeat previous search, but crossing file boundaries. The
268 effect is as if the previous search were modified by *.
270 ESC-N Repeat previous search, but in the reverse direction and cross-
273 ESC-u Undo search highlighting. Turn off highlighting of strings
274 matching the current search pattern. If highlighting is already
275 off because of a previous ESC-u command, turn highlighting back
276 on. Any search command will also turn highlighting back on.
277 (Highlighting can also be disabled by toggling the -G option; in
278 that case search commands do not turn highlighting back on.)
281 Display only lines which match the pattern; lines which do not
282 match the pattern are not displayed. If pattern is empty (if
283 you type & immediately followed by ENTER), any filtering is
284 turned off, and all lines are displayed. While filtering is in
285 effect, an ampersand is displayed at the beginning of the
286 prompt, as a reminder that some lines in the file may be hidden.
288 Certain characters are special as in the / command:
291 Display only lines which do NOT match the pattern.
293 ^R Don't interpret regular expression metacharacters; that
294 is, do a simple textual comparison.
297 Examine a new file. If the filename is missing, the "current"
298 file (see the :n and :p commands below) from the list of files
299 in the command line is re-examined. A percent sign (%) in the
300 filename is replaced by the name of the current file. A pound
301 sign (#) is replaced by the name of the previously examined
302 file. However, two consecutive percent signs are simply
303 replaced with a single percent sign. This allows you to enter a
304 filename that contains a percent sign in the name. Similarly,
305 two consecutive pound signs are replaced with a single pound
306 sign. The filename is inserted into the command line list of
307 files so that it can be seen by subsequent :n and :p commands.
308 If the filename consists of several files, they are all inserted
309 into the list of files and the first one is examined. If the
310 filename contains one or more spaces, the entire filename should
311 be enclosed in double quotes (also see the -" option).
314 Same as :e. Warning: some systems use ^V as a special literal-
315 ization character. On such systems, you may not be able to use
318 :n Examine the next file (from the list of files given in the com-
319 mand line). If a number N is specified, the N-th next file is
322 :p Examine the previous file in the command line list. If a number
323 N is specified, the N-th previous file is examined.
325 :x Examine the first file in the command line list. If a number N
326 is specified, the N-th file in the list is examined.
328 :d Remove the current file from the list of files.
330 t Go to the next tag, if there were more than one matches for the
331 current tag. See the -t option for more details about tags.
333 T Go to the previous tag, if there were more than one matches for
337 Prints some information about the file being viewed, including
338 its name and the line number and byte offset of the bottom line
339 being displayed. If possible, it also prints the length of the
340 file, the number of lines in the file and the percent of the
341 file above the last displayed line.
343 - Followed by one of the command line option letters (see OPTIONS
344 below), this will change the setting of that option and print a
345 message describing the new setting. If a ^P (CONTROL-P) is
346 entered immediately after the dash, the setting of the option is
347 changed but no message is printed. If the option letter has a
348 numeric value (such as -b or -h), or a string value (such as -P
349 or -t), a new value may be entered after the option letter. If
350 no new value is entered, a message describing the current set-
351 ting is printed and nothing is changed.
353 -- Like the - command, but takes a long option name (see OPTIONS
354 below) rather than a single option letter. You must press ENTER
355 or RETURN after typing the option name. A ^P immediately after
356 the second dash suppresses printing of a message describing the
357 new setting, as in the - command.
359 -+ Followed by one of the command line option letters this will
360 reset the option to its default setting and print a message
361 describing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
362 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
363 string-valued options.
365 --+ Like the -+ command, but takes a long option name rather than a
366 single option letter.
368 -! Followed by one of the command line option letters, this will
369 reset the option to the "opposite" of its default setting and
370 print a message describing the new setting. This does not work
371 for numeric or string-valued options.
373 --! Like the -! command, but takes a long option name rather than a
374 single option letter.
376 _ (Underscore.) Followed by one of the command line option let-
377 ters, this will print a message describing the current setting
378 of that option. The setting of the option is not changed.
380 __ (Double underscore.) Like the _ (underscore) command, but takes
381 a long option name rather than a single option letter. You must
382 press ENTER or RETURN after typing the option name.
384 +cmd Causes the specified cmd to be executed each time a new file is
385 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
386 file starting at the end rather than the beginning.
388 V Prints the version number of
\e[4mless
\e[24m being run.
390 q or Q or :q or :Q or ZZ
391 Exits
\e[4mless.
\e[0m
393 The following four commands may or may not be valid, depending on your
394 particular installation.
396 v Invokes an editor to edit the current file being viewed. The
397 editor is taken from the environment variable VISUAL if defined,
398 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
399 ther VISUAL nor EDITOR is defined. See also the discussion of
400 LESSEDIT under the section on PROMPTS below.
403 Invokes a shell to run the shell-command given. A percent sign
404 (%) in the command is replaced by the name of the current file.
405 A pound sign (#) is replaced by the name of the previously exam-
406 ined file. "!!" repeats the last shell command. "!" with no
407 shell command simply invokes a shell. On Unix systems, the
408 shell is taken from the environment variable SHELL, or defaults
409 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
413 <m> represents any mark letter. Pipes a section of the input
414 file to the given shell command. The section of the file to be
415 piped is between the first line on the current screen and the
416 position marked by the letter. <m> may also be ^ or $ to indi-
417 cate beginning or end of file respectively. If <m> is . or new-
418 line, the current screen is piped.
421 Save the input to a file. This only works if the input is a
422 pipe, not an ordinary file.
425 Command line options are described below. Most options may be changed
426 while
\e[4mless
\e[24m is running, via the "-" command.
428 Most options may be given in one of two forms: either a dash followed
429 by a single letter, or two dashes followed by a long option name. A
430 long option name may be abbreviated as long as the abbreviation is
431 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
432 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
433 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
434 from --quit-at-eof. Such option names need only have their first let-
435 ter capitalized; the remainder of the name may be in either case. For
436 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
438 Options are also taken from the environment variable "LESS". For exam-
439 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
440 might tell
\e[4mcsh:
\e[0m
442 setenv LESS "-options"
444 or if you use
\e[4msh:
\e[0m
446 LESS="-options"; export LESS
448 On MS-DOS, you don't need the quotes, but you should replace any per-
449 cent signs in the options string by double percent signs.
451 The environment variable is parsed before the command line, so command
452 line options override the LESS environment variable. If an option
453 appears in the LESS variable, it can be reset to its default value on
454 the command line by beginning the command line option with "-+".
456 Some options like -k or -D require a string to follow the option let-
457 ter. The string for that option is considered to end when a dollar
458 sign ($) is found. For example, you can set two -D options on MS-DOS
463 If the --use-backslash option appears earlier in the options, then a
464 dollar sign or backslash may be included literally in an option string
465 by preceding it with a backslash. If the --use-backslash option is not
466 in effect, then backslashes are not treated specially, and there is no
467 way to include a dollar sign in the option string.
470 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
471 (the same as the h command). (Depending on how your shell
472 interprets the question mark, it may be necessary to quote the
473 question mark, thus: "-\?".)
475 -a or --search-skip-screen
476 By default, forward searches start at the top of the displayed
477 screen and backwards searches start at the bottom of the dis-
478 played screen (except for repeated searches invoked by the n or
479 N commands, which start after or before the "target" line
480 respectively; see the -j option for more about the target line).
481 The -a option causes forward searches to instead start at the
482 bottom of the screen and backward searches to start at the top
483 of the screen, thus skipping all lines displayed on the screen.
485 -A or --SEARCH-SKIP-SCREEN
486 Causes all forward searches (not just non-repeated searches) to
487 start just after the target line, and all backward searches to
488 start just before the target line. Thus, forward searches will
489 skip part of the displayed screen (from the first line up to and
490 including the target line). Similarly backwards searches will
491 skip the displayed screen from the last line up to and including
492 the target line. This was the default behavior in less versions
495 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
496 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
497 file, in units of kilobytes (1024 bytes). By default 64 K of
498 buffer space is used for each file (unless the file is a pipe;
499 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
500 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
501 -1, buffer space is unlimited; that is, the entire file can be
505 By default, when data is read from a pipe, buffers are allocated
506 automatically as needed. If a large amount of data is read from
507 the pipe, this can cause a large amount of memory to be allo-
508 cated. The -B option disables this automatic allocation of buf-
509 fers for pipes, so that only 64 K (or the amount of space speci-
510 fied by the -b option) is used for the pipe. Warning: use of -B
511 can result in erroneous display, since only the most recently
512 viewed part of the piped data is kept in memory; any earlier
516 Causes full screen repaints to be painted from the top line
517 down. By default, full screen repaints are done by scrolling
518 from the bottom of the screen.
521 Same as -c, for compatibility with older versions of
\e[4mless.
\e[0m
524 The -d option suppresses the error message normally displayed if
525 the terminal is dumb; that is, lacks some important capability,
526 such as the ability to clear the screen or scroll backward. The
527 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
530 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
531 [MS-DOS only] Sets the color of the text displayed.
\e[1mx
\e[22mis a sin-
532 gle character which selects the type of text whose color is
533 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
534 \e[4mcolor
\e[24m is a pair of numbers separated by a period. The first
535 number selects the foreground color and the second selects the
536 background color of the text. A single number
\e[4mN
\e[24m is the same as
537 \e[4mN.M
\e[24m, where
\e[4mM
\e[24m is the normal background color.
\e[1mx
\e[22mmay also be
\e[1ma
\e[22mto
538 toggle strict ANSI sequence rendering (SGR mode).
542 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
543 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
547 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
551 Forces non-regular files to be opened. (A non-regular file is a
552 directory or a device special file.) Also suppresses the warn-
553 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
554 refuse to open non-regular files. Note that some operating sys-
555 tems will not allow directories to be read, even if -f is set.
557 -F or --quit-if-one-screen
558 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
559 played on the first screen.
561 -g or --hilite-search
562 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
563 search command. The -g option changes this behavior to high-
564 light only the particular string which was found by the last
565 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
568 -G or --HILITE-SEARCH
569 The -G option suppresses all highlighting of strings found by
572 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
573 Specifies a maximum number of lines to scroll backward. If it
574 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
575 repainted in a forward direction instead. (If the terminal does
576 not have the ability to scroll backward, -h0 is implied.)
579 Causes searches to ignore case; that is, uppercase and lowercase
580 are considered identical. This option is ignored if any upper-
581 case letters appear in the search pattern; in other words, if a
582 pattern contains uppercase letters, then that search does not
586 Like -i, but searches ignore case even if the pattern contains
589 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
590 Specifies a line on the screen where the "target" line is to be
591 positioned. The target line is the line specified by any com-
592 mand to search for a pattern, jump to a line number, jump to a
593 file percentage or jump to a tag. The screen line may be speci-
594 fied by a number: the top line on the screen is 1, the next is
595 2, and so on. The number may be negative to specify a line rel-
596 ative to the bottom of the screen: the bottom line on the screen
597 is -1, the second to the bottom is -2, and so on. Alternately,
598 the screen line may be specified as a fraction of the height of
599 the screen, starting with a decimal point: .5 is in the middle
600 of the screen, .3 is three tenths down from the first line, and
601 so on. If the line is specified as a fraction, the actual line
602 number is recalculated if the terminal window is resized, so
603 that the target line remains at the specified fraction of the
604 screen height. If any form of the -j option is used, repeated
605 forward searches (invoked with "n" or "N") begin at the line
606 immediately after the target line, and repeated backward
607 searches begin at the target line, unless changed by -a or -A.
608 For example, if "-j4" is used, the target line is the fourth
609 line on the screen, so forward searches begin at the fifth line
610 on the screen. However nonrepeated searches (invoked with "/"
611 or "?") always begin at the start or end of the current screen
614 -J or --status-column
615 Displays a status column at the left edge of the screen. The
616 status column shows the lines that matched the current search.
617 The status column is also used if the -w or -W option is in
620 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
621 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[0m
622 (1) file. Multiple -k options may be specified. If the LESSKEY
623 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
624 file is found in a standard place (see KEY BINDINGS), it is also
625 used as a
\e[4mlesskey
\e[24m file.
628 Causes
\e[4mless
\e[24m to exit immediately (with status 2) when an inter-
629 rupt character (usually ^C) is typed. Normally, an interrupt
630 character causes
\e[4mless
\e[24m to stop whatever it is doing and return to
631 its command prompt. Note that use of this option makes it
632 impossible to return to the command prompt from the "F" command.
635 Ignore the LESSOPEN environment variable (see the INPUT PRE-
636 PROCESSOR section below). This option can be set from within
637 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
638 to the file which is currently open.
641 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
642 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
645 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore.
\e[0m
648 Suppresses line numbers. The default (to use line numbers) may
649 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
650 very large input file. Suppressing line numbers with the -n
651 option will avoid this problem. Using line numbers means: the
652 line number will be displayed in the verbose prompt and in the =
653 command, and the v command will pass the current line number to
654 the editor (see also the discussion of LESSEDIT in PROMPTS
658 Causes a line number to be displayed at the beginning of each
661 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
662 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
663 viewed. This applies only when the input file is a pipe, not an
664 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
665 confirmation before overwriting it.
667 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
668 The -O option is like -o, but it will overwrite an existing file
669 without asking for confirmation.
671 If no log file has been specified, the -o and -O options can be
672 used from within
\e[4mless
\e[24m to specify a log file. Without a file
673 name, they will simply report the name of the log file. The "s"
674 command is equivalent to specifying -o from within
\e[4mless.
\e[0m
676 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
677 The -p option on the command line is equivalent to specifying
678 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
679 rence of
\e[4mpattern
\e[24m in the file.
681 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
682 Provides a way to tailor the three prompt styles to your own
683 preference. This option would normally be put in the LESS envi-
684 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
685 mand. Such an option must either be the last option in the LESS
686 variable, or be terminated by a dollar sign.
687 -Ps followed by a string changes the default (short) prompt to
689 -Pm changes the medium (-m) prompt.
690 -PM changes the long (-M) prompt.
691 -Ph changes the prompt for the help screen.
692 -P= changes the message printed by the = command.
693 -Pw changes the message printed while waiting for data (in the
694 F command). All prompt strings consist of a sequence of letters
695 and special escape sequences. See the section on PROMPTS for
698 -q or --quiet or --silent
699 Causes moderately "quiet" operation: the terminal bell is not
700 rung if an attempt is made to scroll past the end of the file or
701 before the beginning of the file. If the terminal has a "visual
702 bell", it is used instead. The bell will be rung on certain
703 other errors, such as typing an invalid character. The default
704 is to ring the terminal bell in all such cases.
706 -Q or --QUIET or --SILENT
707 Causes totally "quiet" operation: the terminal bell is never
710 -r or --raw-control-chars
711 Causes "raw" control characters to be displayed. The default is
712 to display control characters using the caret notation; for
713 example, a control-A (octal 001) is displayed as "^A". Warning:
714 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
715 appearance of the screen (since this depends on how the screen
716 responds to each type of control character). Thus, various dis-
717 play problems may result, such as long lines being split in the
720 -R or --RAW-CONTROL-CHARS
721 Like -r, but only ANSI "color" escape sequences are output in
722 "raw" form. Unlike -r, the screen appearance is maintained cor-
723 rectly in most cases. ANSI "color" escape sequences are
724 sequences of the form:
728 where the "..." is zero or more color specification characters
729 For the purpose of keeping track of screen appearance, ANSI
730 color escape sequences are assumed to not move the cursor. You
731 can make
\e[4mless
\e[24m think that characters other than "m" can end ANSI
732 color escape sequences by setting the environment variable
733 LESSANSIENDCHARS to the list of characters which can end a color
734 escape sequence. And you can make
\e[4mless
\e[24m think that characters
735 other than the standard ones may appear between the ESC and the
736 m by setting the environment variable LESSANSIMIDCHARS to the
737 list of characters which can appear.
739 -s or --squeeze-blank-lines
740 Causes consecutive blank lines to be squeezed into a single
741 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
743 -S or --chop-long-lines
744 Causes lines longer than the screen width to be chopped (trun-
745 cated) rather than wrapped. That is, the portion of a long line
746 that does not fit in the screen width is not shown. The default
747 is to wrap long lines; that is, display the remainder on the
750 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
751 The -t option, followed immediately by a TAG, will edit the file
752 containing that tag. For this to work, tag information must be
753 available; for example, there may be a file in the current
754 directory called "tags", which was previously built by
\e[4mctags
\e[24m (1)
755 or an equivalent command. If the environment variable LESSGLOB-
756 ALTAGS is set, it is taken to be the name of a command compati-
757 ble with
\e[4mglobal
\e[24m (1), and that command is executed to find the
758 tag. (See http://www.gnu.org/software/global/global.html). The
759 -t option may also be specified from within
\e[4mless
\e[24m (using the -
760 command) as a way of examining a new file. The command ":t" is
761 equivalent to specifying -t from within
\e[4mless.
\e[0m
763 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
764 Specifies a tags file to be used instead of "tags".
766 -u or --underline-special
767 Causes backspaces and carriage returns to be treated as print-
768 able characters; that is, they are sent to the terminal when
769 they appear in the input.
771 -U or --UNDERLINE-SPECIAL
772 Causes backspaces, tabs and carriage returns to be treated as
773 control characters; that is, they are handled as specified by
776 By default, if neither -u nor -U is given, backspaces which
777 appear adjacent to an underscore character are treated spe-
778 cially: the underlined text is displayed using the terminal's
779 hardware underlining capability. Also, backspaces which appear
780 between two identical characters are treated specially: the
781 overstruck text is printed using the terminal's hardware bold-
782 face capability. Other backspaces are deleted, along with the
783 preceding character. Carriage returns immediately followed by a
784 newline are deleted. Other carriage returns are handled as
785 specified by the -r option. Text which is overstruck or under-
786 lined can be searched for if neither -u nor -U is in effect.
789 Displays the version number of
\e[4mless.
\e[0m
791 -w or --hilite-unread
792 Temporarily highlights the first "new" line after a forward
793 movement of a full page. The first "new" line is the line imme-
794 diately following the line previously at the bottom of the
795 screen. Also highlights the target line after a g or p command.
796 The highlight is removed at the next command which causes move-
797 ment. The entire line is highlighted, unless the -J option is
798 in effect, in which case only the status column is highlighted.
800 -W or --HILITE-UNREAD
801 Like -w, but temporarily highlights the first new line after any
802 forward movement command larger than one line.
804 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
805 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
806 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
807 specified, tab stops are set at those positions, and then con-
808 tinue with the same spacing as the last two. For example,
809 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The
810 default for
\e[4mn
\e[24m is 8.
813 Disables sending the termcap initialization and deinitialization
814 strings to the terminal. This is sometimes desirable if the
815 deinitialization string does something unnecessary, like clear-
818 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
819 Specifies a maximum number of lines to scroll forward. If it is
820 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is
821 repainted instead. The -c or -C option may be used to repaint
822 from the top of the screen if desired. By default, any forward
823 movement causes scrolling.
825 -[z]
\e[4mn
\e[24m or --window=
\e[4mn
\e[0m
826 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The
827 default is one screenful. The z and w commands can also be used
828 to change the window size. The "z" may be omitted for compati-
829 bility with some versions of
\e[4mmore.
\e[24m If the number
\e[4mn
\e[24m is negative,
830 it indicates
\e[4mn
\e[24m lines less than the current screen size. For
831 example, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling win-
832 dow to 20 lines. If the screen is resized to 40 lines, the
833 scrolling window automatically changes to 36 lines.
835 -
\e[4m"cc
\e[24m or --quotes=
\e[4mcc
\e[0m
836 Changes the filename quoting character. This may be necessary
837 if you are trying to name a file which contains both spaces and
838 quote characters. Followed by a single character, this changes
839 the quote character to that character. Filenames containing a
840 space should then be surrounded by that character rather than by
841 double quotes. Followed by two characters, changes the open
842 quote to the first character, and the close quote to the second
843 character. Filenames containing a space should then be preceded
844 by the open quote character and followed by the close quote
845 character. Note that even after the quote characters are
846 changed, this option remains -" (a dash followed by a double
850 Normally lines after end of file are displayed as a single tilde
851 (~). This option causes lines after end of file to be displayed
855 Specifies the default number of positions to scroll horizontally
856 in the RIGHTARROW and LEFTARROW commands. If the number speci-
857 fied is zero, it sets the default number of positions to one
858 half of the screen width. Alternately, the number may be speci-
859 fied as a fraction of the width of the screen, starting with a
860 decimal point: .5 is half of the screen width, .3 is three
861 tenths of the screen width, and so on. If the number is speci-
862 fied as a fraction, the actual number of scroll positions is
863 recalculated if the terminal window is resized, so that the
864 actual scroll remains at the specified fraction of the screen
868 Normally, if the input file is renamed while an F command is
869 executing,
\e[4mless
\e[24m will continue to display the contents of the
870 original file despite its name change. If --follow-name is
871 specified, during an F command
\e[4mless
\e[24m will periodically attempt to
872 reopen the file by name. If the reopen succeeds and the file is
873 a different file from the original (which means that a new file
874 has been created with the same name as the original (now
875 renamed) file),
\e[4mless
\e[24m will display the contents of that new file.
878 Disables sending the keypad initialization and deinitialization
879 strings to the terminal. This is sometimes useful if the keypad
880 strings make the numeric keypad behave in an undesirable manner.
883 This option changes the interpretations of options which follow
884 this one. After the --use-backslash option, any backslash in an
885 option string is removed and the following character is taken
886 literally. This allows a dollar sign to be included in option
889 -- A command line argument of "--" marks the end of option argu-
890 ments. Any arguments following this are interpreted as file-
891 names. This can be useful when viewing a file whose name begins
894 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
895 option is taken to be an initial command to
\e[4mless.
\e[24m For example,
896 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
897 beginning, and +/xyz tells it to start at the first occurrence
898 of "xyz" in the file. As a special case, +<number> acts like
899 +<number>g; that is, it starts the display at the specified line
900 number (however, see the caveat under the "g" command above).
901 If the option starts with ++, the initial command applies to
902 every file being viewed, not just the first one. The + command
903 described previously may also be used to set (or change) an ini-
904 tial command for every file.
907 \e[1mLINE EDITING
\e[0m
908 When entering command line at the bottom of the screen (for example, a
909 filename for the :e command, or the pattern for a search command), cer-
910 tain keys can be used to manipulate the command line. Most commands
911 have an alternate form in [ brackets ] which can be used if a key does
912 not exist on a particular keyboard. (Note that the forms beginning
913 with ESC do not work in some MS-DOS and Windows systems because ESC is
914 the line erase character.) Any of these special keys may be entered
915 literally by preceding it with the "literal" character, either ^V or
916 ^A. A backslash itself may also be entered literally by entering two
920 Move the cursor one space to the left.
923 Move the cursor one space to the right.
925 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
926 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
927 sor one word to the left.
929 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
930 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
931 sor one word to the right.
934 Move the cursor to the beginning of the line.
937 Move the cursor to the end of the line.
940 Delete the character to the left of the cursor, or cancel the
941 command if the command line is empty.
944 Delete the character under the cursor.
946 ^BACKSPACE [ ESC-BACKSPACE ]
947 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
948 word to the left of the cursor.
950 ^DELETE [ ESC-X or ESC-DELETE ]
951 (That is, CONTROL and DELETE simultaneously.) Delete the word
955 Retrieve the previous command line. If you first enter some
956 text and then press UPARROW, it will retrieve the previous com-
957 mand which begins with that text.
960 Retrieve the next command line. If you first enter some text
961 and then press DOWNARROW, it will retrieve the next command
962 which begins with that text.
964 TAB Complete the partial filename to the left of the cursor. If it
965 matches more than one filename, the first match is entered into
966 the command line. Repeated TABs will cycle thru the other
967 matching filenames. If the completed filename is a directory, a
968 "/" is appended to the filename. (On MS-DOS systems, a "\" is
969 appended.) The environment variable LESSSEPARATOR can be used
970 to specify a different character to append to a directory name.
973 Like, TAB, but cycles in the reverse direction thru the matching
976 ^L Complete the partial filename to the left of the cursor. If it
977 matches more than one filename, all matches are entered into the
978 command line (if they fit).
980 ^U (Unix and OS/2) or ESC (MS-DOS)
981 Delete the entire command line, or cancel the command if the
982 command line is empty. If you have changed your line-kill char-
983 acter in Unix to something other than ^U, that character is used
986 ^G Delete the entire command line and return to the main prompt.
989 \e[1mKEY BINDINGS
\e[0m
990 You may define your own
\e[4mless
\e[24m commands by using the program
\e[4mlesskey
\e[24m (1)
991 to create a lesskey file. This file specifies a set of command keys
992 and an action associated with each key. You may also use
\e[4mlesskey
\e[24m to
993 change the line-editing keys (see LINE EDITING), and to set environment
994 variables. If the environment variable LESSKEY is set,
\e[4mless
\e[24m uses that
995 as the name of the lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard
996 place for the lesskey file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey
997 file called "$HOME/.less". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks
998 for a lesskey file called "$HOME/_less", and if it is not found there,
999 then looks for a lesskey file called "_less" in any directory specified
1000 in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for a
1001 lesskey file called "$HOME/less.ini", and if it is not found, then
1002 looks for a lesskey file called "less.ini" in any directory specified
1003 in the INIT environment variable, and if it not found there, then looks
1004 for a lesskey file called "less.ini" in any directory specified in the
1005 PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for more
1008 A system-wide lesskey file may also be set up to provide key bindings.
1009 If a key is defined in both a local lesskey file and in the system-wide
1010 file, key bindings in the local file take precedence over those in the
1011 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
1012 \e[4mless
\e[24m uses that as the name of the system-wide lesskey file. Otherwise,
1013 \e[4mless
\e[24m looks in a standard place for the system-wide lesskey file: On
1014 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1015 (However, if
\e[4mless
\e[24m was built with a different sysconf directory than
1016 /usr/local/etc, that directory is where the sysless file is found.) On
1017 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys-
1018 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
1021 \e[1mINPUT PREPROCESSOR
\e[0m
1022 You may define an "input preprocessor" for
\e[4mless.
\e[24m Before
\e[4mless
\e[24m opens a
1023 file, it first gives your input preprocessor a chance to modify the way
1024 the contents of the file are displayed. An input preprocessor is sim-
1025 ply an executable program (or shell script), which writes the contents
1026 of the file to a different file, called the replacement file. The con-
1027 tents of the replacement file are then displayed in place of the con-
1028 tents of the original file. However, it will appear to the user as if
1029 the original file is opened; that is,
\e[4mless
\e[24m will display the original
1030 filename as the name of the current file.
1032 An input preprocessor receives one command line argument, the original
1033 filename, as entered by the user. It should create the replacement
1034 file, and when finished, print the name of the replacement file to its
1035 standard output. If the input preprocessor does not output a replace-
1036 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
1037 processor is not called when viewing standard input. To set up an
1038 input preprocessor, set the LESSOPEN environment variable to a command
1039 line which will invoke your input preprocessor. This command line
1040 should include one occurrence of the string "%s", which will be
1041 replaced by the filename when the input preprocessor command is
1044 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
1045 gram, called the input postprocessor, which may perform any desired
1046 clean-up action (such as deleting the replacement file created by
1047 LESSOPEN). This program receives two command line arguments, the orig-
1048 inal filename as entered by the user, and the name of the replacement
1049 file. To set up an input postprocessor, set the LESSCLOSE environment
1050 variable to a command line which will invoke your input postprocessor.
1051 It may include two occurrences of the string "%s"; the first is
1052 replaced with the original name of the file and the second with the
1053 name of the replacement file, which was output by LESSOPEN.
1055 For example, on many Unix systems, these two scripts will allow you to
1056 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1061 *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1062 if [ -s /tmp/less.$$ ]; then
1074 To use these scripts, put them both where they can be executed and set
1075 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1076 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1077 types of compressed files, and so on.
1079 It is also possible to set up an input preprocessor to pipe the file
1080 data directly to
\e[4mless,
\e[24m rather than putting the data into a replacement
1081 file. This avoids the need to decompress the entire file before start-
1082 ing to view it. An input preprocessor that works this way is called an
1083 input pipe. An input pipe, instead of writing the name of a replace-
1084 ment file on its standard output, writes the entire contents of the
1085 replacement file on its standard output. If the input pipe does not
1086 write any characters on its standard output, then there is no replace-
1087 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1088 pipe, make the first character in the LESSOPEN environment variable a
1089 vertical bar (|) to signify that the input preprocessor is an input
1092 For example, on many Unix systems, this script will work like the pre-
1093 vious example scripts:
1098 *.Z) uncompress -c $1 2>/dev/null
1104 To use this script, put it where it can be executed and set
1105 LESSOPEN="|lesspipe.sh %s".
1107 Note that a preprocessor cannot output an empty file, since that is
1108 interpreted as meaning there is no replacement, and the original file
1109 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1110 exit status of the script becomes meaningful. If the exit status is
1111 zero, the output is considered to be replacement text, even if it
1112 empty. If the exit status is nonzero, any output is ignored and the
1113 original file is used. For compatibility with previous versions of
1114 \e[4mless,
\e[24m if LESSOPEN starts with only one vertical bar, the exit status of
1115 the preprocessor is ignored.
1117 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1118 it is usually not necessary since there is no replacement file to clean
1119 up. In this case, the replacement file name passed to the LESSCLOSE
1120 postprocessor is "-".
1122 For compatibility with previous versions of
\e[4mless,
\e[24m the input preproces-
1123 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1124 the first character of LESSOPEN is a dash (-), the input preprocessor
1125 is used on standard input as well as other files. In this case, the
1126 dash is not considered to be part of the preprocessor command. If
1127 standard input is being viewed, the input preprocessor is passed a file
1128 name consisting of a single dash. Similarly, if the first two charac-
1129 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1130 and a dash (||-), the input pipe is used on standard input as well as
1131 other files. Again, in this case the dash is not considered to be part
1132 of the input pipe command.
1135 \e[1mNATIONAL CHARACTER SETS
\e[0m
1136 There are three types of characters in the input file:
1139 can be displayed directly to the screen.
1142 should not be displayed directly, but are expected to be found
1143 in ordinary text files (such as backspace and tab).
1146 should not be displayed directly and are not expected to be
1147 found in text files.
1149 A "character set" is simply a description of which characters are to be
1150 considered normal, control, and binary. The LESSCHARSET environment
1151 variable may be used to select a character set. Possible values for
1154 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1155 with values between 32 and 126 are normal, and all others are
1159 Selects an ISO 8859 character set. This is the same as ASCII,
1160 except characters between 160 and 255 are treated as normal
1163 latin1 Same as iso8859.
1165 latin9 Same as iso8859.
1167 dos Selects a character set appropriate for MS-DOS.
1169 ebcdic Selects an EBCDIC character set.
1172 Selects an EBCDIC character set used by OS/390 Unix Services.
1173 This is the EBCDIC analogue of latin1. You get similar results
1174 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1177 koi8-r Selects a Russian character set.
1179 next Selects a character set appropriate for NeXT computers.
1181 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1182 UTF-8 is special in that it supports multi-byte characters in
1183 the input file. It is the only character set that supports
1184 multi-byte characters.
1187 Selects a character set appropriate for Microsoft Windows (cp
1190 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1191 other than the ones definable by LESSCHARSET. In this case, the envi-
1192 ronment variable LESSCHARDEF can be used to define a character set. It
1193 should be set to a string where each character in the string represents
1194 one character in the character set. The character "." is used for a
1195 normal character, "c" for control, and "b" for binary. A decimal num-
1196 ber may be used for repetition. For example, "bccc4b." would mean
1197 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1198 binary, and 8 is normal. All characters after the last are taken to be
1199 the same as the last, so characters 9 through 255 would be normal.
1200 (This is an example, and does not necessarily represent any real char-
1203 This table shows the value of LESSCHARDEF which is equivalent to each
1204 of the possible values for LESSCHARSET:
1206 ascii 8bcccbcc18b95.b
1207 dos 8bcccbcc12bc5b95.b.
1208 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1209 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1210 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1212 iso8859 8bcccbcc18b95.33b.
1213 koi8-r 8bcccbcc18b95.b128.
1214 latin1 8bcccbcc18b95.33b.
1215 next 8bcccbcc18b95.bb125.bb
1217 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1218 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1219 LANG environment variables, then the default character set is utf-8.
1221 If that string is not found, but your system supports the
\e[4msetlocale
\e[0m
1222 interface,
\e[4mless
\e[24m will use setlocale to determine the character set.
1223 setlocale is controlled by setting the LANG or LC_CTYPE environment
1226 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1227 character set is latin1.
1229 Control and binary characters are displayed in standout (reverse
1230 video). Each such character is displayed in caret notation if possible
1231 (e.g. ^A for control-A). Caret notation is used only if inverting the
1232 0100 bit results in a normal printable character. Otherwise, the char-
1233 acter is displayed as a hex number in angle brackets. This format can
1234 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1235 may begin with a "*" and one character to select the display attribute:
1236 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1237 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1238 attribute is assumed. The remainder of LESSBINFMT is a string which
1239 may include one printf-style escape sequence (a % followed by x, X, o,
1240 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1241 are displayed in underlined hexadecimal surrounded by brackets. The
1242 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1243 result of expanding the character via LESSBINFMT must be less than 31
1246 When the character set is utf-8, the LESSUTFBINFMT environment variable
1247 acts similarly to LESSBINFMT but it applies to Unicode code points that
1248 were successfully decoded but are unsuitable for display (e.g., unas-
1249 signed code points). Its default value is "<U+%04lX>". Note that
1250 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1251 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1252 LESSBINFMT so its setting, if any, will have priority. Problematic
1253 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1254 complete but non-shortest form sequence, illegal octets, and stray
1255 trailing octets) are displayed individually using LESSBINFMT so as to
1256 facilitate diagnostic of how the UTF-8 file is ill-formed.
1260 The -P option allows you to tailor the prompt to your preference. The
1261 string given to the -P option replaces the specified prompt string.
1262 Certain characters in the string are interpreted specially. The prompt
1263 mechanism is rather complicated to provide flexibility, but the ordi-
1264 nary user need not understand the details of constructing personalized
1267 A percent sign followed by a single character is expanded according to
1268 what the following character is:
1270 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1271 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1272 ifies the line whose byte offset is to be used. If the charac-
1273 ter is a "t", the byte offset of the top line in the display is
1274 used, an "m" means use the middle line, a "b" means use the bot-
1275 tom line, a "B" means use the line just after the bottom line,
1276 and a "j" means use the "target" line, as specified by the -j
1279 %B Replaced by the size of the current input file.
1281 %c Replaced by the column number of the text appearing in the first
1282 column of the screen.
1284 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1285 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1287 %D Replaced by the number of pages in the input file, or equiva-
1288 lently, the page number of the last line in the input file.
1290 %E Replaced by the name of the editor (from the VISUAL environment
1291 variable, or the EDITOR environment variable if VISUAL is not
1292 defined). See the discussion of the LESSEDIT feature below.
1294 %f Replaced by the name of the current input file.
1296 %F Replaced by the last component of the name of the current input
1299 %i Replaced by the index of the current file in the list of input
1302 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1303 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1305 %L Replaced by the line number of the last line in the input file.
1307 %m Replaced by the total number of input files.
1309 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1310 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1313 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1314 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1319 %t Causes any trailing spaces to be removed. Usually used at the
1320 end of the string, but may appear anywhere.
1322 %T Normally expands to the word "file". However if viewing files
1323 via a tags list using the -t option, it expands to the word
1326 %x Replaced by the name of the next input file in the list.
1328 If any item is unknown (for example, the file size if input is a pipe),
1329 a question mark is printed instead.
1331 The format of the prompt string can be changed depending on certain
1332 conditions. A question mark followed by a single character acts like
1333 an "IF": depending on the following character, a condition is evalu-
1334 ated. If the condition is true, any characters following the question
1335 mark and condition character, up to a period, are included in the
1336 prompt. If the condition is false, such characters are not included.
1337 A colon appearing between the question mark and the period can be used
1338 to establish an "ELSE": any characters between the colon and the period
1339 are included in the string if and only if the IF condition is false.
1340 Condition characters (which follow a question mark) may be:
1342 ?a True if any characters have been included in the prompt so far.
1344 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1346 ?B True if the size of current input file is known.
1348 ?c True if the text is horizontally shifted (%c is not zero).
1350 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1352 ?e True if at end-of-file.
1354 ?f True if there is an input filename (that is, if input is not a
1357 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1359 ?L True if the line number of the last line in the file is known.
1361 ?m True if there is more than one input file.
1363 ?n True if this is the first prompt in a new input file.
1365 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1366 offsets, of the specified line is known.
1368 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1369 numbers, of the specified line is known.
1373 ?x True if there is a next input file (that is, if the current
1374 input file is not the last one).
1376 Any characters other than the special ones (question mark, colon,
1377 period, percent, and backslash) become literally part of the prompt.
1378 Any of the special characters may be included in the prompt literally
1379 by preceding it with a backslash.
1383 ?f%f:Standard input.
1385 This prompt prints the filename, if known; otherwise the string "Stan-
1388 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1390 This prompt would print the filename, if known. The filename is fol-
1391 lowed by the line number, if known, otherwise the percent if known,
1392 otherwise the byte offset if known. Otherwise, a dash is printed.
1393 Notice how each question mark has a matching period, and how the %
1394 after the %pt is included literally by escaping it with a backslash.
1396 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1398 This prints the filename if this is the first prompt in a file, fol-
1399 lowed by the "file N of N" message if there is more than one input
1400 file. Then, if we are at end-of-file, the string "(END)" is printed
1401 followed by the name of the next file, if there is one. Finally, any
1402 trailing spaces are truncated. This is the default prompt. For refer-
1403 ence, here are the defaults for the other two prompts (-m and -M
1404 respectively). Each is broken into two lines here for readability
1407 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1408 ?pB%pB\%:byte %bB?s/%s...%t
1410 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1411 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1413 And here is the default message produced by the = command:
1415 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1416 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1418 The prompt expansion features are also used for another purpose: if an
1419 environment variable LESSEDIT is defined, it is used as the command to
1420 be executed when the v command is invoked. The LESSEDIT string is
1421 expanded in the same way as the prompt strings. The default value for
1426 Note that this expands to the editor name, followed by a + and the line
1427 number, followed by the file name. If your editor does not accept the
1428 "+linenumber" syntax, or has other differences in invocation syntax,
1429 the LESSEDIT variable can be changed to modify this default.
1433 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1434 "secure" mode. This means these features are disabled:
1440 :e the examine command.
1442 v the editing command
1446 -k use of lesskey files
1448 -t use of tags files
1450 metacharacters in filenames, such as *
1452 filename completion (TAB, ^L)
1454 Less can also be compiled to be permanently in "secure" mode.
1457 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1458 If the environment variable LESS_IS_MORE is set to 1, or if the program
1459 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1460 formance with the POSIX "more" command specification. In this mode,
1461 less behaves differently in these ways:
1463 The -e option works differently. If the -e option is not set,
\e[4mless
\e[0m
1464 behaves as if the -e option were set. If the -e option is set,
\e[4mless
\e[0m
1465 behaves as if the -E option were set.
1467 The -m option works differently. If the -m option is not set, the
1468 medium prompt is used, and it is prefixed with the string "--More--".
1469 If the -m option is set, the short prompt is used.
1471 The -n option acts like the -z option. The normal behavior of the -n
1472 option is unavailable in this mode.
1474 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1475 than a search pattern.
1477 The LESS environment variable is ignored, and the MORE environment
1478 variable is used in its place.
1481 \e[1mENVIRONMENT VARIABLES
\e[0m
1482 Environment variables may be specified either in the system environment
1483 as usual, or in a
\e[4mlesskey
\e[24m (1) file. If environment variables are
1484 defined in more than one place, variables defined in a local lesskey
1485 file take precedence over variables defined in the system environment,
1486 which take precedence over variables defined in the system-wide lesskey
1490 Sets the number of columns on the screen. Takes precedence over
1491 the number of columns specified by the TERM variable. (But if
1492 you have a windowing system which supports TIOCGWINSZ or
1493 WIOCGETD, the window system's idea of the screen size takes
1494 precedence over the LINES and COLUMNS environment variables.)
1496 EDITOR The name of the editor (used for the v command).
1498 HOME Name of the user's home directory (used to find a lesskey file
1499 on Unix and OS/2 systems).
1502 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1503 ables is the name of the user's home directory if the HOME vari-
1504 able is not set (only in the Windows version).
1506 INIT Name of the user's init directory (used to find a lesskey file
1509 LANG Language for determining the character set.
1512 Language for determining the character set.
1514 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1517 Characters which may end an ANSI color escape sequence (default
1521 Characters which may appear between the ESC character and the
1522 end character in an ANSI color escape sequence (default
1523 "0123456789:;[?!"'#%()*+ ".
1526 Format for displaying non-printable, non-control characters.
1529 Defines a character set.
1532 Selects a predefined character set.
1535 Command line to invoke the (optional) input-postprocessor.
1538 Name of the lessecho program (default "lessecho"). The lessecho
1539 program is needed to expand metacharacters, such as * and ?, in
1540 filenames on Unix systems.
1543 Editor prototype string (used for the v command). See discus-
1547 Name of the command used by the -t option to find global tags.
1548 Normally should be set to "global" if your system has the
\e[4mglobal
\e[0m
1549 (1) command. If not set, global tags are not used.
1552 Name of the history file used to remember search commands and
1553 shell commands between invocations of
\e[4mless.
\e[24m If set to "-" or
1554 "/dev/null", a history file is not used. The default is
1555 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1556 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1560 The maximum number of commands to save in the history file. The
1564 Name of the default lesskey(1) file.
1567 Name of the default system-wide lesskey(1) file.
1570 List of characters which are considered "metacharacters" by the
1574 Prefix which less will add before each metacharacter in a com-
1575 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1576 commands containing metacharacters will not be passed to the
1580 Command line to invoke the (optional) input-preprocessor.
1583 Runs less in "secure" mode. See discussion under SECURITY.
1586 String to be appended to a directory name in filename comple-
1590 Format for displaying non-printable Unicode code points.
1593 Emulate the
\e[4mmore
\e[24m (1) command.
1595 LINES Sets the number of lines on the screen. Takes precedence over
1596 the number of lines specified by the TERM variable. (But if you
1597 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1598 the window system's idea of the screen size takes precedence
1599 over the LINES and COLUMNS environment variables.)
1601 MORE Options which are passed to
\e[4mless
\e[24m automatically when running in
1602 \e[4mmore
\e[24m compatible mode.
1604 PATH User's search path (used to find a lesskey file on MS-DOS and
1607 SHELL The shell used to execute the ! command, as well as to expand
1610 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1612 VISUAL The name of the editor (used for the v command).
1620 Copyright (C) 1984-2016 Mark Nudelman
1622 less is part of the GNU project and is free software. You can redis-
1623 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1624 eral Public License as published by the Free Software Foundation; or
1625 (2) the Less License. See the file README in the less distribution for
1626 more details regarding redistribution. You should have received a copy
1627 of the GNU General Public License along with the source for less; see
1628 the file COPYING. If not, write to the Free Software Foundation, 59
1629 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1630 have received a copy of the Less License; see the file LICENSE.
1632 less is distributed in the hope that it will be useful, but WITHOUT ANY
1633 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1634 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1640 Send bug reports or comments to <bug-less@gnu.org>
1641 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1642 of known bugs in less.
1643 For more information, see the less homepage at
1644 http://www.greenwoodsoftware.com/less.
1648 Version 487: 25 Oct 2016 LESS(1)
projects / platform / upstream / less.git / blob