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 or uppercase letter, marks the first
179 displayed line with that letter. If the status column is
180 enabled via the -J option, the status column shows the marked
183 M Acts like m, except the last displayed line is marked rather
184 than the first displayed line.
186 ' (Single quote.) Followed by any lowercase or uppercase letter,
187 returns to the position which was previously marked with that
188 letter. Followed by another single quote, returns to the posi-
189 tion at which the last "large" movement command was executed.
190 Followed by a ^ or $, jumps to the beginning or end of the file
191 respectively. Marks are preserved when a new file is examined,
192 so the ' command can be used to switch between input files.
194 ^X^X Same as single quote.
196 ESC-m Followed by any lowercase or uppercase letter, clears the mark
197 identified by that letter.
200 Search forward in the file for the N-th line containing the pat-
201 tern. N defaults to 1. The pattern is a regular expression, as
202 recognized by the regular expression library supplied by your
203 system. The search starts at the first line displayed (but see
204 the -a and -j options, which change this).
206 Certain characters are special if entered at the beginning of
207 the pattern; they modify the type of search rather than become
211 Search for lines which do NOT match the pattern.
214 Search multiple files. That is, if the search reaches
215 the END of the current file without finding a match, the
216 search continues in the next file in the command line
220 Begin the search at the first line of the FIRST file in
221 the command line list, regardless of what is currently
222 displayed on the screen or the settings of the -a or -j
225 ^K Highlight any text which matches the pattern on the cur-
226 rent screen, but don't move to the first match (KEEP cur-
229 ^R Don't interpret regular expression metacharacters; that
230 is, do a simple textual comparison.
233 Search backward in the file for the N-th line containing the
234 pattern. The search starts at the last line displayed (but see
235 the -a and -j options, which change this).
237 Certain characters are special as in the / command:
240 Search for lines which do NOT match the pattern.
243 Search multiple files. That is, if the search reaches
244 the beginning of the current file without finding a
245 match, the search continues in the previous file in the
249 Begin the search at the last line of the last file in the
250 command line list, regardless of what is currently dis-
251 played on the screen or the settings of the -a or -j
254 ^K As in forward searches.
256 ^R As in forward searches.
264 n Repeat previous search, for N-th line containing the last pat-
265 tern. If the previous search was modified by ^N, the search is
266 made for the N-th line NOT containing the pattern. If the pre-
267 vious search was modified by ^E, the search continues in the
268 next (or previous) file if not satisfied in the current file.
269 If the previous search was modified by ^R, the search is done
270 without using regular expressions. There is no effect if the
271 previous search was modified by ^F or ^K.
273 N Repeat previous search, but in the reverse direction.
275 ESC-n Repeat previous search, but crossing file boundaries. The
276 effect is as if the previous search were modified by *.
278 ESC-N Repeat previous search, but in the reverse direction and cross-
281 ESC-u Undo search highlighting. Turn off highlighting of strings
282 matching the current search pattern. If highlighting is already
283 off because of a previous ESC-u command, turn highlighting back
284 on. Any search command will also turn highlighting back on.
285 (Highlighting can also be disabled by toggling the -G option; in
286 that case search commands do not turn highlighting back on.)
289 Display only lines which match the pattern; lines which do not
290 match the pattern are not displayed. If pattern is empty (if
291 you type & immediately followed by ENTER), any filtering is
292 turned off, and all lines are displayed. While filtering is in
293 effect, an ampersand is displayed at the beginning of the
294 prompt, as a reminder that some lines in the file may be hidden.
296 Certain characters are special as in the / command:
299 Display only lines which do NOT match the pattern.
301 ^R Don't interpret regular expression metacharacters; that
302 is, do a simple textual comparison.
305 Examine a new file. If the filename is missing, the "current"
306 file (see the :n and :p commands below) from the list of files
307 in the command line is re-examined. A percent sign (%) in the
308 filename is replaced by the name of the current file. A pound
309 sign (#) is replaced by the name of the previously examined
310 file. However, two consecutive percent signs are simply
311 replaced with a single percent sign. This allows you to enter a
312 filename that contains a percent sign in the name. Similarly,
313 two consecutive pound signs are replaced with a single pound
314 sign. The filename is inserted into the command line list of
315 files so that it can be seen by subsequent :n and :p commands.
316 If the filename consists of several files, they are all inserted
317 into the list of files and the first one is examined. If the
318 filename contains one or more spaces, the entire filename should
319 be enclosed in double quotes (also see the -" option).
322 Same as :e. Warning: some systems use ^V as a special literal-
323 ization character. On such systems, you may not be able to use
326 :n Examine the next file (from the list of files given in the com-
327 mand line). If a number N is specified, the N-th next file is
330 :p Examine the previous file in the command line list. If a number
331 N is specified, the N-th previous file is examined.
333 :x Examine the first file in the command line list. If a number N
334 is specified, the N-th file in the list is examined.
336 :d Remove the current file from the list of files.
338 t Go to the next tag, if there were more than one matches for the
339 current tag. See the -t option for more details about tags.
341 T Go to the previous tag, if there were more than one matches for
345 Prints some information about the file being viewed, including
346 its name and the line number and byte offset of the bottom line
347 being displayed. If possible, it also prints the length of the
348 file, the number of lines in the file and the percent of the
349 file above the last displayed line.
351 - Followed by one of the command line option letters (see OPTIONS
352 below), this will change the setting of that option and print a
353 message describing the new setting. If a ^P (CONTROL-P) is
354 entered immediately after the dash, the setting of the option is
355 changed but no message is printed. If the option letter has a
356 numeric value (such as -b or -h), or a string value (such as -P
357 or -t), a new value may be entered after the option letter. If
358 no new value is entered, a message describing the current set-
359 ting is printed and nothing is changed.
361 -- Like the - command, but takes a long option name (see OPTIONS
362 below) rather than a single option letter. You must press ENTER
363 or RETURN after typing the option name. A ^P immediately after
364 the second dash suppresses printing of a message describing the
365 new setting, as in the - command.
367 -+ Followed by one of the command line option letters this will
368 reset the option to its default setting and print a message
369 describing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
370 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
371 string-valued options.
373 --+ Like the -+ command, but takes a long option name rather than a
374 single option letter.
376 -! Followed by one of the command line option letters, this will
377 reset the option to the "opposite" of its default setting and
378 print a message describing the new setting. This does not work
379 for numeric or string-valued options.
381 --! Like the -! command, but takes a long option name rather than a
382 single option letter.
384 _ (Underscore.) Followed by one of the command line option let-
385 ters, this will print a message describing the current setting
386 of that option. The setting of the option is not changed.
388 __ (Double underscore.) Like the _ (underscore) command, but takes
389 a long option name rather than a single option letter. You must
390 press ENTER or RETURN after typing the option name.
392 +cmd Causes the specified cmd to be executed each time a new file is
393 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
394 file starting at the end rather than the beginning.
396 V Prints the version number of
\e[4mless
\e[24m being run.
398 q or Q or :q or :Q or ZZ
399 Exits
\e[4mless
\e[24m.
401 The following four commands may or may not be valid, depending on your
402 particular installation.
404 v Invokes an editor to edit the current file being viewed. The
405 editor is taken from the environment variable VISUAL if defined,
406 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
407 ther VISUAL nor EDITOR is defined. See also the discussion of
408 LESSEDIT under the section on PROMPTS below.
411 Invokes a shell to run the shell-command given. A percent sign
412 (%) in the command is replaced by the name of the current file.
413 A pound sign (#) is replaced by the name of the previously exam-
414 ined file. "!!" repeats the last shell command. "!" with no
415 shell command simply invokes a shell. On Unix systems, the
416 shell is taken from the environment variable SHELL, or defaults
417 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
421 <m> represents any mark letter. Pipes a section of the input
422 file to the given shell command. The section of the file to be
423 piped is between the position marked by the letter and the cur-
424 rent screen. The entire current screen is included, regardless
425 of whether the marked position is before or after the current
426 screen. <m> may also be ^ or $ to indicate beginning or end of
427 file respectively. If <m> is . or newline, the current screen
431 Save the input to a file. This only works if the input is a
432 pipe, not an ordinary file.
435 Command line options are described below. Most options may be changed
436 while
\e[4mless
\e[24m is running, via the "-" command.
438 Most options may be given in one of two forms: either a dash followed
439 by a single letter, or two dashes followed by a long option name. A
440 long option name may be abbreviated as long as the abbreviation is
441 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
442 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
443 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
444 from --quit-at-eof. Such option names need only have their first let-
445 ter capitalized; the remainder of the name may be in either case. For
446 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
448 Options are also taken from the environment variable "LESS". For exam-
449 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
450 might tell
\e[4mcsh
\e[24m:
452 setenv LESS "-options"
454 or if you use
\e[4msh
\e[24m:
456 LESS="-options"; export LESS
458 On MS-DOS, you don't need the quotes, but you should replace any per-
459 cent signs in the options string by double percent signs.
461 The environment variable is parsed before the command line, so command
462 line options override the LESS environment variable. If an option
463 appears in the LESS variable, it can be reset to its default value on
464 the command line by beginning the command line option with "-+".
466 Some options like -k or -D require a string to follow the option let-
467 ter. The string for that option is considered to end when a dollar
468 sign ($) is found. For example, you can set two -D options on MS-DOS
473 If the --use-backslash option appears earlier in the options, then a
474 dollar sign or backslash may be included literally in an option string
475 by preceding it with a backslash. If the --use-backslash option is not
476 in effect, then backslashes are not treated specially, and there is no
477 way to include a dollar sign in the option string.
480 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
481 (the same as the h command). (Depending on how your shell
482 interprets the question mark, it may be necessary to quote the
483 question mark, thus: "-\?".)
485 -a or --search-skip-screen
486 By default, forward searches start at the top of the displayed
487 screen and backwards searches start at the bottom of the dis-
488 played screen (except for repeated searches invoked by the n or
489 N commands, which start after or before the "target" line
490 respectively; see the -j option for more about the target line).
491 The -a option causes forward searches to instead start at the
492 bottom of the screen and backward searches to start at the top
493 of the screen, thus skipping all lines displayed on the screen.
495 -A or --SEARCH-SKIP-SCREEN
496 Causes all forward searches (not just non-repeated searches) to
497 start just after the target line, and all backward searches to
498 start just before the target line. Thus, forward searches will
499 skip part of the displayed screen (from the first line up to and
500 including the target line). Similarly backwards searches will
501 skip the displayed screen from the last line up to and including
502 the target line. This was the default behavior in less versions
505 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
506 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
507 file, in units of kilobytes (1024 bytes). By default 64 K of
508 buffer space is used for each file (unless the file is a pipe;
509 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
510 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
511 -1, buffer space is unlimited; that is, the entire file can be
515 By default, when data is read from a pipe, buffers are allocated
516 automatically as needed. If a large amount of data is read from
517 the pipe, this can cause a large amount of memory to be allo-
518 cated. The -B option disables this automatic allocation of buf-
519 fers for pipes, so that only 64 K (or the amount of space speci-
520 fied by the -b option) is used for the pipe. Warning: use of -B
521 can result in erroneous display, since only the most recently
522 viewed part of the piped data is kept in memory; any earlier
526 Causes full screen repaints to be painted from the top line
527 down. By default, full screen repaints are done by scrolling
528 from the bottom of the screen.
531 Same as -c, for compatibility with older versions of
\e[4mless
\e[24m.
534 The -d option suppresses the error message normally displayed if
535 the terminal is dumb; that is, lacks some important capability,
536 such as the ability to clear the screen or scroll backward. The
537 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
540 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
541 [MS-DOS only] Sets the color of the text displayed.
\e[1mx
\e[22mis a sin-
542 gle character which selects the type of text whose color is
543 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
544 \e[4mcolor
\e[24m is a pair of numbers separated by a period. The first
545 number selects the foreground color and the second selects the
546 background color of the text. A single number
\e[4mN
\e[24m is the same as
547 \e[4mN.M
\e[24m, where
\e[4mM
\e[24m is the normal background color. The color may
548 start or end with
\e[1mu
\e[22mto use underline (with the normal color, if
549 by itself), if the system supports it (Windows only).
\e[1mx
\e[22mmay
550 also be
\e[1ma
\e[22mto toggle strict ANSI sequence rendering (SGR mode).
554 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
555 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
559 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
563 Forces non-regular files to be opened. (A non-regular file is a
564 directory or a device special file.) Also suppresses the warn-
565 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
566 refuse to open non-regular files. Note that some operating sys-
567 tems will not allow directories to be read, even if -f is set.
569 -F or --quit-if-one-screen
570 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
571 played on the first screen.
573 -g or --hilite-search
574 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
575 search command. The -g option changes this behavior to high-
576 light only the particular string which was found by the last
577 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
580 -G or --HILITE-SEARCH
581 The -G option suppresses all highlighting of strings found by
584 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
585 Specifies a maximum number of lines to scroll backward. If it
586 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
587 repainted in a forward direction instead. (If the terminal does
588 not have the ability to scroll backward, -h0 is implied.)
591 Causes searches to ignore case; that is, uppercase and lowercase
592 are considered identical. This option is ignored if any upper-
593 case letters appear in the search pattern; in other words, if a
594 pattern contains uppercase letters, then that search does not
598 Like -i, but searches ignore case even if the pattern contains
601 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
602 Specifies a line on the screen where the "target" line is to be
603 positioned. The target line is the line specified by any com-
604 mand to search for a pattern, jump to a line number, jump to a
605 file percentage or jump to a tag. The screen line may be speci-
606 fied by a number: the top line on the screen is 1, the next is
607 2, and so on. The number may be negative to specify a line rel-
608 ative to the bottom of the screen: the bottom line on the screen
609 is -1, the second to the bottom is -2, and so on. Alternately,
610 the screen line may be specified as a fraction of the height of
611 the screen, starting with a decimal point: .5 is in the middle
612 of the screen, .3 is three tenths down from the first line, and
613 so on. If the line is specified as a fraction, the actual line
614 number is recalculated if the terminal window is resized, so
615 that the target line remains at the specified fraction of the
616 screen height. If any form of the -j option is used, repeated
617 forward searches (invoked with "n" or "N") begin at the line
618 immediately after the target line, and repeated backward
619 searches begin at the target line, unless changed by -a or -A.
620 For example, if "-j4" is used, the target line is the fourth
621 line on the screen, so forward searches begin at the fifth line
622 on the screen. However nonrepeated searches (invoked with "/"
623 or "?") always begin at the start or end of the current screen
626 -J or --status-column
627 Displays a status column at the left edge of the screen. The
628 status column shows the lines that matched the current search,
629 and any lines that are marked (via the m or M command). The
630 status column is also used if the -w or -W option is in effect.
632 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
633 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[0m
634 (1) file. Multiple -k options may be specified. If the LESSKEY
635 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
636 file is found in a standard place (see KEY BINDINGS), it is also
637 used as a
\e[4mlesskey
\e[24m file.
640 Causes
\e[4mless
\e[24m to exit immediately (with status 2) when an inter-
641 rupt character (usually ^C) is typed. Normally, an interrupt
642 character causes
\e[4mless
\e[24m to stop whatever it is doing and return to
643 its command prompt. Note that use of this option makes it
644 impossible to return to the command prompt from the "F" command.
647 Ignore the LESSOPEN environment variable (see the INPUT PRE-
648 PROCESSOR section below). This option can be set from within
649 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
650 to the file which is currently open.
653 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
654 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
657 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore
\e[24m.
660 Suppresses line numbers. The default (to use line numbers) may
661 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
662 very large input file. Suppressing line numbers with the -n
663 option will avoid this problem. Using line numbers means: the
664 line number will be displayed in the verbose prompt and in the =
665 command, and the v command will pass the current line number to
666 the editor (see also the discussion of LESSEDIT in PROMPTS
670 Causes a line number to be displayed at the beginning of each
673 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
674 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
675 viewed. This applies only when the input file is a pipe, not an
676 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
677 confirmation before overwriting it.
679 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
680 The -O option is like -o, but it will overwrite an existing file
681 without asking for confirmation.
683 If no log file has been specified, the -o and -O options can be
684 used from within
\e[4mless
\e[24m to specify a log file. Without a file
685 name, they will simply report the name of the log file. The "s"
686 command is equivalent to specifying -o from within
\e[4mless
\e[24m.
688 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
689 The -p option on the command line is equivalent to specifying
690 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
691 rence of
\e[4mpattern
\e[24m in the file.
693 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
694 Provides a way to tailor the three prompt styles to your own
695 preference. This option would normally be put in the LESS envi-
696 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
697 mand. Such an option must either be the last option in the LESS
698 variable, or be terminated by a dollar sign.
699 -Ps followed by a string changes the default (short) prompt to
701 -Pm changes the medium (-m) prompt.
702 -PM changes the long (-M) prompt.
703 -Ph changes the prompt for the help screen.
704 -P= changes the message printed by the = command.
705 -Pw changes the message printed while waiting for data (in the
708 All prompt strings consist of a sequence of letters and special
709 escape sequences. See the section on PROMPTS for more details.
711 -q or --quiet or --silent
712 Causes moderately "quiet" operation: the terminal bell is not
713 rung if an attempt is made to scroll past the end of the file or
714 before the beginning of the file. If the terminal has a "visual
715 bell", it is used instead. The bell will be rung on certain
716 other errors, such as typing an invalid character. The default
717 is to ring the terminal bell in all such cases.
719 -Q or --QUIET or --SILENT
720 Causes totally "quiet" operation: the terminal bell is never
723 -r or --raw-control-chars
724 Causes "raw" control characters to be displayed. The default is
725 to display control characters using the caret notation; for
726 example, a control-A (octal 001) is displayed as "^A". Warning:
727 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
728 appearance of the screen (since this depends on how the screen
729 responds to each type of control character). Thus, various dis-
730 play problems may result, such as long lines being split in the
733 -R or --RAW-CONTROL-CHARS
734 Like -r, but only ANSI "color" escape sequences are output in
735 "raw" form. Unlike -r, the screen appearance is maintained cor-
736 rectly in most cases. ANSI "color" escape sequences are
737 sequences of the form:
741 where the "..." is zero or more color specification characters
742 For the purpose of keeping track of screen appearance, ANSI
743 color escape sequences are assumed to not move the cursor. You
744 can make
\e[4mless
\e[24m think that characters other than "m" can end ANSI
745 color escape sequences by setting the environment variable
746 LESSANSIENDCHARS to the list of characters which can end a color
747 escape sequence. And you can make
\e[4mless
\e[24m think that characters
748 other than the standard ones may appear between the ESC and the
749 m by setting the environment variable LESSANSIMIDCHARS to the
750 list of characters which can appear.
752 -s or --squeeze-blank-lines
753 Causes consecutive blank lines to be squeezed into a single
754 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
756 -S or --chop-long-lines
757 Causes lines longer than the screen width to be chopped (trun-
758 cated) rather than wrapped. That is, the portion of a long line
759 that does not fit in the screen width is not shown. The default
760 is to wrap long lines; that is, display the remainder on the
763 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
764 The -t option, followed immediately by a TAG, will edit the file
765 containing that tag. For this to work, tag information must be
766 available; for example, there may be a file in the current
767 directory called "tags", which was previously built by
\e[4mctags
\e[24m (1)
768 or an equivalent command. If the environment variable LESSGLOB-
769 ALTAGS is set, it is taken to be the name of a command compati-
770 ble with
\e[4mglobal
\e[24m (1), and that command is executed to find the
771 tag. (See http://www.gnu.org/software/global/global.html). The
772 -t option may also be specified from within
\e[4mless
\e[24m (using the -
773 command) as a way of examining a new file. The command ":t" is
774 equivalent to specifying -t from within
\e[4mless
\e[24m.
776 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
777 Specifies a tags file to be used instead of "tags".
779 -u or --underline-special
780 Causes backspaces and carriage returns to be treated as print-
781 able characters; that is, they are sent to the terminal when
782 they appear in the input.
784 -U or --UNDERLINE-SPECIAL
785 Causes backspaces, tabs, carriage returns and "formatting char-
786 acters" (as defined by Unicode) to be treated as control charac-
787 ters; that is, they are handled as specified by the -r option.
789 By default, if neither -u nor -U is given, backspaces which
790 appear adjacent to an underscore character are treated spe-
791 cially: the underlined text is displayed using the terminal's
792 hardware underlining capability. Also, backspaces which appear
793 between two identical characters are treated specially: the
794 overstruck text is printed using the terminal's hardware bold-
795 face capability. Other backspaces are deleted, along with the
796 preceding character. Carriage returns immediately followed by a
797 newline are deleted. Other carriage returns are handled as
798 specified by the -r option. Text which is overstruck or under-
799 lined can be searched for if neither -u nor -U is in effect.
802 Displays the version number of
\e[4mless
\e[24m.
804 -w or --hilite-unread
805 Temporarily highlights the first "new" line after a forward
806 movement of a full page. The first "new" line is the line imme-
807 diately following the line previously at the bottom of the
808 screen. Also highlights the target line after a g or p command.
809 The highlight is removed at the next command which causes move-
810 ment. The entire line is highlighted, unless the -J option is
811 in effect, in which case only the status column is highlighted.
813 -W or --HILITE-UNREAD
814 Like -w, but temporarily highlights the first new line after any
815 forward movement command larger than one line.
817 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
818 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
819 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
820 specified, tab stops are set at those positions, and then con-
821 tinue with the same spacing as the last two. For example,
822 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The
823 default for
\e[4mn
\e[24m is 8.
826 Disables sending the termcap initialization and deinitialization
827 strings to the terminal. This is sometimes desirable if the
828 deinitialization string does something unnecessary, like clear-
831 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
832 Specifies a maximum number of lines to scroll forward. If it is
833 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is
834 repainted instead. The -c or -C option may be used to repaint
835 from the top of the screen if desired. By default, any forward
836 movement causes scrolling.
838 -z
\e[4mn
\e[24m or --window=
\e[4mn
\e[24m or -
\e[4mn
\e[0m
839 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The
840 default is one screenful. The z and w commands can also be used
841 to change the window size. The "z" may be omitted for compati-
842 bility with some versions of
\e[4mmore
\e[24m. If the number
\e[4mn
\e[24m is negative,
843 it indicates
\e[4mn
\e[24m lines less than the current screen size. For
844 example, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling win-
845 dow to 20 lines. If the screen is resized to 40 lines, the
846 scrolling window automatically changes to 36 lines.
848 -"
\e[4mcc
\e[24m or --quotes=
\e[4mcc
\e[0m
849 Changes the filename quoting character. This may be necessary
850 if you are trying to name a file which contains both spaces and
851 quote characters. Followed by a single character, this changes
852 the quote character to that character. Filenames containing a
853 space should then be surrounded by that character rather than by
854 double quotes. Followed by two characters, changes the open
855 quote to the first character, and the close quote to the second
856 character. Filenames containing a space should then be preceded
857 by the open quote character and followed by the close quote
858 character. Note that even after the quote characters are
859 changed, this option remains -" (a dash followed by a double
863 Normally lines after end of file are displayed as a single tilde
864 (~). This option causes lines after end of file to be displayed
868 Specifies the default number of positions to scroll horizontally
869 in the RIGHTARROW and LEFTARROW commands. If the number speci-
870 fied is zero, it sets the default number of positions to one
871 half of the screen width. Alternately, the number may be speci-
872 fied as a fraction of the width of the screen, starting with a
873 decimal point: .5 is half of the screen width, .3 is three
874 tenths of the screen width, and so on. If the number is speci-
875 fied as a fraction, the actual number of scroll positions is
876 recalculated if the terminal window is resized, so that the
877 actual scroll remains at the specified fraction of the screen
881 Normally, if the input file is renamed while an F command is
882 executing,
\e[4mless
\e[24m will continue to display the contents of the
883 original file despite its name change. If --follow-name is
884 specified, during an F command
\e[4mless
\e[24m will periodically attempt to
885 reopen the file by name. If the reopen succeeds and the file is
886 a different file from the original (which means that a new file
887 has been created with the same name as the original (now
888 renamed) file),
\e[4mless
\e[24m will display the contents of that new file.
891 Disables sending the keypad initialization and deinitialization
892 strings to the terminal. This is sometimes useful if the keypad
893 strings make the numeric keypad behave in an undesirable manner.
896 This option changes the interpretations of options which follow
897 this one. After the --use-backslash option, any backslash in an
898 option string is removed and the following character is taken
899 literally. This allows a dollar sign to be included in option
903 This option changes the character used to mark truncated lines.
904 It may begin with a two-character attribute indicator like LESS-
905 BINFMT does. If there is no attribute indicator, standout is
906 used. If set to "-", truncated lines are not marked.
908 -- A command line argument of "--" marks the end of option argu-
909 ments. Any arguments following this are interpreted as file-
910 names. This can be useful when viewing a file whose name begins
913 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
914 option is taken to be an initial command to
\e[4mless
\e[24m. For example,
915 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
916 beginning, and +/xyz tells it to start at the first occurrence
917 of "xyz" in the file. As a special case, +<number> acts like
918 +<number>g; that is, it starts the display at the specified line
919 number (however, see the caveat under the "g" command above).
920 If the option starts with ++, the initial command applies to
921 every file being viewed, not just the first one. The + command
922 described previously may also be used to set (or change) an ini-
923 tial command for every file.
926 \e[1mLINE EDITING
\e[0m
927 When entering command line at the bottom of the screen (for example, a
928 filename for the :e command, or the pattern for a search command), cer-
929 tain keys can be used to manipulate the command line. Most commands
930 have an alternate form in [ brackets ] which can be used if a key does
931 not exist on a particular keyboard. (Note that the forms beginning
932 with ESC do not work in some MS-DOS and Windows systems because ESC is
933 the line erase character.) Any of these special keys may be entered
934 literally by preceding it with the "literal" character, either ^V or
935 ^A. A backslash itself may also be entered literally by entering two
939 Move the cursor one space to the left.
942 Move the cursor one space to the right.
944 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
945 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
946 sor one word to the left.
948 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
949 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
950 sor one word to the right.
953 Move the cursor to the beginning of the line.
956 Move the cursor to the end of the line.
959 Delete the character to the left of the cursor, or cancel the
960 command if the command line is empty.
963 Delete the character under the cursor.
965 ^BACKSPACE [ ESC-BACKSPACE ]
966 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
967 word to the left of the cursor.
969 ^DELETE [ ESC-X or ESC-DELETE ]
970 (That is, CONTROL and DELETE simultaneously.) Delete the word
974 Retrieve the previous command line. If you first enter some
975 text and then press UPARROW, it will retrieve the previous com-
976 mand which begins with that text.
979 Retrieve the next command line. If you first enter some text
980 and then press DOWNARROW, it will retrieve the next command
981 which begins with that text.
983 TAB Complete the partial filename to the left of the cursor. If it
984 matches more than one filename, the first match is entered into
985 the command line. Repeated TABs will cycle thru the other
986 matching filenames. If the completed filename is a directory, a
987 "/" is appended to the filename. (On MS-DOS systems, a "\" is
988 appended.) The environment variable LESSSEPARATOR can be used
989 to specify a different character to append to a directory name.
992 Like, TAB, but cycles in the reverse direction thru the matching
995 ^L Complete the partial filename to the left of the cursor. If it
996 matches more than one filename, all matches are entered into the
997 command line (if they fit).
999 ^U (Unix and OS/2) or ESC (MS-DOS)
1000 Delete the entire command line, or cancel the command if the
1001 command line is empty. If you have changed your line-kill char-
1002 acter in Unix to something other than ^U, that character is used
1005 ^G Delete the entire command line and return to the main prompt.
1008 \e[1mKEY BINDINGS
\e[0m
1009 You may define your own
\e[4mless
\e[24m commands by using the program
\e[4mlesskey
\e[24m (1)
1010 to create a lesskey file. This file specifies a set of command keys
1011 and an action associated with each key. You may also use
\e[4mlesskey
\e[24m to
1012 change the line-editing keys (see LINE EDITING), and to set environment
1013 variables. If the environment variable LESSKEY is set,
\e[4mless
\e[24m uses that
1014 as the name of the lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard
1015 place for the lesskey file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey
1016 file called "$HOME/.less". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks
1017 for a lesskey file called "$HOME/_less", and if it is not found there,
1018 then looks for a lesskey file called "_less" in any directory specified
1019 in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for a
1020 lesskey file called "$HOME/less.ini", and if it is not found, then
1021 looks for a lesskey file called "less.ini" in any directory specified
1022 in the INIT environment variable, and if it not found there, then looks
1023 for a lesskey file called "less.ini" in any directory specified in the
1024 PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for more
1027 A system-wide lesskey file may also be set up to provide key bindings.
1028 If a key is defined in both a local lesskey file and in the system-wide
1029 file, key bindings in the local file take precedence over those in the
1030 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
1031 \e[4mless
\e[24m uses that as the name of the system-wide lesskey file. Otherwise,
1032 \e[4mless
\e[24m looks in a standard place for the system-wide lesskey file: On
1033 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1034 (However, if
\e[4mless
\e[24m was built with a different sysconf directory than
1035 /usr/local/etc, that directory is where the sysless file is found.) On
1036 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys-
1037 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
1040 \e[1mINPUT PREPROCESSOR
\e[0m
1041 You may define an "input preprocessor" for
\e[4mless
\e[24m. Before
\e[4mless
\e[24m opens a
1042 file, it first gives your input preprocessor a chance to modify the way
1043 the contents of the file are displayed. An input preprocessor is sim-
1044 ply an executable program (or shell script), which writes the contents
1045 of the file to a different file, called the replacement file. The con-
1046 tents of the replacement file are then displayed in place of the con-
1047 tents of the original file. However, it will appear to the user as if
1048 the original file is opened; that is,
\e[4mless
\e[24m will display the original
1049 filename as the name of the current file.
1051 An input preprocessor receives one command line argument, the original
1052 filename, as entered by the user. It should create the replacement
1053 file, and when finished, print the name of the replacement file to its
1054 standard output. If the input preprocessor does not output a replace-
1055 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
1056 processor is not called when viewing standard input. To set up an
1057 input preprocessor, set the LESSOPEN environment variable to a command
1058 line which will invoke your input preprocessor. This command line
1059 should include one occurrence of the string "%s", which will be
1060 replaced by the filename when the input preprocessor command is
1063 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
1064 gram, called the input postprocessor, which may perform any desired
1065 clean-up action (such as deleting the replacement file created by
1066 LESSOPEN). This program receives two command line arguments, the orig-
1067 inal filename as entered by the user, and the name of the replacement
1068 file. To set up an input postprocessor, set the LESSCLOSE environment
1069 variable to a command line which will invoke your input postprocessor.
1070 It may include two occurrences of the string "%s"; the first is
1071 replaced with the original name of the file and the second with the
1072 name of the replacement file, which was output by LESSOPEN.
1074 For example, on many Unix systems, these two scripts will allow you to
1075 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1080 *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1081 if [ -s /tmp/less.$$ ]; then
1093 To use these scripts, put them both where they can be executed and set
1094 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1095 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1096 types of compressed files, and so on.
1098 It is also possible to set up an input preprocessor to pipe the file
1099 data directly to
\e[4mless
\e[24m, rather than putting the data into a replacement
1100 file. This avoids the need to decompress the entire file before start-
1101 ing to view it. An input preprocessor that works this way is called an
1102 input pipe. An input pipe, instead of writing the name of a replace-
1103 ment file on its standard output, writes the entire contents of the
1104 replacement file on its standard output. If the input pipe does not
1105 write any characters on its standard output, then there is no replace-
1106 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1107 pipe, make the first character in the LESSOPEN environment variable a
1108 vertical bar (|) to signify that the input preprocessor is an input
1109 pipe. As with non-pipe input preprocessors, the command string must
1110 contain one occurrence of %s, which is replaced with the filename of
1113 For example, on many Unix systems, this script will work like the pre-
1114 vious example scripts:
1119 *.Z) uncompress -c $1 2>/dev/null
1125 To use this script, put it where it can be executed and set
1126 LESSOPEN="|lesspipe.sh %s".
1128 Note that a preprocessor cannot output an empty file, since that is
1129 interpreted as meaning there is no replacement, and the original file
1130 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1131 exit status of the script becomes meaningful. If the exit status is
1132 zero, the output is considered to be replacement text, even if it is
1133 empty. If the exit status is nonzero, any output is ignored and the
1134 original file is used. For compatibility with previous versions of
1135 \e[4mless
\e[24m, if LESSOPEN starts with only one vertical bar, the exit status of
1136 the preprocessor is ignored.
1138 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1139 it is usually not necessary since there is no replacement file to clean
1140 up. In this case, the replacement file name passed to the LESSCLOSE
1141 postprocessor is "-".
1143 For compatibility with previous versions of
\e[4mless
\e[24m, the input preproces-
1144 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1145 the first character of LESSOPEN is a dash (-), the input preprocessor
1146 is used on standard input as well as other files. In this case, the
1147 dash is not considered to be part of the preprocessor command. If
1148 standard input is being viewed, the input preprocessor is passed a file
1149 name consisting of a single dash. Similarly, if the first two charac-
1150 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1151 and a dash (||-), the input pipe is used on standard input as well as
1152 other files. Again, in this case the dash is not considered to be part
1153 of the input pipe command.
1156 \e[1mNATIONAL CHARACTER SETS
\e[0m
1157 There are three types of characters in the input file:
1160 can be displayed directly to the screen.
1163 should not be displayed directly, but are expected to be found
1164 in ordinary text files (such as backspace and tab).
1167 should not be displayed directly and are not expected to be
1168 found in text files.
1170 A "character set" is simply a description of which characters are to be
1171 considered normal, control, and binary. The LESSCHARSET environment
1172 variable may be used to select a character set. Possible values for
1175 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1176 with values between 32 and 126 are normal, and all others are
1180 Selects an ISO 8859 character set. This is the same as ASCII,
1181 except characters between 160 and 255 are treated as normal
1184 latin1 Same as iso8859.
1186 latin9 Same as iso8859.
1188 dos Selects a character set appropriate for MS-DOS.
1190 ebcdic Selects an EBCDIC character set.
1193 Selects an EBCDIC character set used by OS/390 Unix Services.
1194 This is the EBCDIC analogue of latin1. You get similar results
1195 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1198 koi8-r Selects a Russian character set.
1200 next Selects a character set appropriate for NeXT computers.
1202 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1203 UTF-8 is special in that it supports multi-byte characters in
1204 the input file. It is the only character set that supports
1205 multi-byte characters.
1208 Selects a character set appropriate for Microsoft Windows (cp
1211 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1212 other than the ones definable by LESSCHARSET. In this case, the envi-
1213 ronment variable LESSCHARDEF can be used to define a character set. It
1214 should be set to a string where each character in the string represents
1215 one character in the character set. The character "." is used for a
1216 normal character, "c" for control, and "b" for binary. A decimal num-
1217 ber may be used for repetition. For example, "bccc4b." would mean
1218 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1219 binary, and 8 is normal. All characters after the last are taken to be
1220 the same as the last, so characters 9 through 255 would be normal.
1221 (This is an example, and does not necessarily represent any real char-
1224 This table shows the value of LESSCHARDEF which is equivalent to each
1225 of the possible values for LESSCHARSET:
1227 ascii 8bcccbcc18b95.b
1228 dos 8bcccbcc12bc5b95.b.
1229 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1230 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1231 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1233 iso8859 8bcccbcc18b95.33b.
1234 koi8-r 8bcccbcc18b95.b128.
1235 latin1 8bcccbcc18b95.33b.
1236 next 8bcccbcc18b95.bb125.bb
1238 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1239 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1240 LANG environment variables, then the default character set is utf-8.
1242 If that string is not found, but your system supports the
\e[4msetlocale
\e[0m
1243 interface,
\e[4mless
\e[24m will use setlocale to determine the character set.
1244 setlocale is controlled by setting the LANG or LC_CTYPE environment
1247 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1248 character set is latin1.
1250 Control and binary characters are displayed in standout (reverse
1251 video). Each such character is displayed in caret notation if possible
1252 (e.g. ^A for control-A). Caret notation is used only if inverting the
1253 0100 bit results in a normal printable character. Otherwise, the char-
1254 acter is displayed as a hex number in angle brackets. This format can
1255 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1256 may begin with a "*" and one character to select the display attribute:
1257 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1258 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1259 attribute is assumed. The remainder of LESSBINFMT is a string which
1260 may include one printf-style escape sequence (a % followed by x, X, o,
1261 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1262 are displayed in underlined hexadecimal surrounded by brackets. The
1263 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1264 result of expanding the character via LESSBINFMT must be less than 31
1267 When the character set is utf-8, the LESSUTFBINFMT environment variable
1268 acts similarly to LESSBINFMT but it applies to Unicode code points that
1269 were successfully decoded but are unsuitable for display (e.g., unas-
1270 signed code points). Its default value is "<U+%04lX>". Note that
1271 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1272 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1273 LESSBINFMT so its setting, if any, will have priority. Problematic
1274 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1275 complete but non-shortest form sequence, illegal octets, and stray
1276 trailing octets) are displayed individually using LESSBINFMT so as to
1277 facilitate diagnostic of how the UTF-8 file is ill-formed.
1281 The -P option allows you to tailor the prompt to your preference. The
1282 string given to the -P option replaces the specified prompt string.
1283 Certain characters in the string are interpreted specially. The prompt
1284 mechanism is rather complicated to provide flexibility, but the ordi-
1285 nary user need not understand the details of constructing personalized
1288 A percent sign followed by a single character is expanded according to
1289 what the following character is:
1291 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1292 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1293 ifies the line whose byte offset is to be used. If the charac-
1294 ter is a "t", the byte offset of the top line in the display is
1295 used, an "m" means use the middle line, a "b" means use the bot-
1296 tom line, a "B" means use the line just after the bottom line,
1297 and a "j" means use the "target" line, as specified by the -j
1300 %B Replaced by the size of the current input file.
1302 %c Replaced by the column number of the text appearing in the first
1303 column of the screen.
1305 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1306 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1308 %D Replaced by the number of pages in the input file, or equiva-
1309 lently, the page number of the last line in the input file.
1311 %E Replaced by the name of the editor (from the VISUAL environment
1312 variable, or the EDITOR environment variable if VISUAL is not
1313 defined). See the discussion of the LESSEDIT feature below.
1315 %f Replaced by the name of the current input file.
1317 %F Replaced by the last component of the name of the current input
1320 %i Replaced by the index of the current file in the list of input
1323 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1324 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1326 %L Replaced by the line number of the last line in the input file.
1328 %m Replaced by the total number of input files.
1330 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1331 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1334 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1335 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1340 %t Causes any trailing spaces to be removed. Usually used at the
1341 end of the string, but may appear anywhere.
1343 %T Normally expands to the word "file". However if viewing files
1344 via a tags list using the -t option, it expands to the word
1347 %x Replaced by the name of the next input file in the list.
1349 If any item is unknown (for example, the file size if input is a pipe),
1350 a question mark is printed instead.
1352 The format of the prompt string can be changed depending on certain
1353 conditions. A question mark followed by a single character acts like
1354 an "IF": depending on the following character, a condition is evalu-
1355 ated. If the condition is true, any characters following the question
1356 mark and condition character, up to a period, are included in the
1357 prompt. If the condition is false, such characters are not included.
1358 A colon appearing between the question mark and the period can be used
1359 to establish an "ELSE": any characters between the colon and the period
1360 are included in the string if and only if the IF condition is false.
1361 Condition characters (which follow a question mark) may be:
1363 ?a True if any characters have been included in the prompt so far.
1365 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1367 ?B True if the size of current input file is known.
1369 ?c True if the text is horizontally shifted (%c is not zero).
1371 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1373 ?e True if at end-of-file.
1375 ?f True if there is an input filename (that is, if input is not a
1378 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1380 ?L True if the line number of the last line in the file is known.
1382 ?m True if there is more than one input file.
1384 ?n True if this is the first prompt in a new input file.
1386 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1387 offsets, of the specified line is known.
1389 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1390 numbers, of the specified line is known.
1394 ?x True if there is a next input file (that is, if the current
1395 input file is not the last one).
1397 Any characters other than the special ones (question mark, colon,
1398 period, percent, and backslash) become literally part of the prompt.
1399 Any of the special characters may be included in the prompt literally
1400 by preceding it with a backslash.
1404 ?f%f:Standard input.
1406 This prompt prints the filename, if known; otherwise the string "Stan-
1409 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1411 This prompt would print the filename, if known. The filename is fol-
1412 lowed by the line number, if known, otherwise the percent if known,
1413 otherwise the byte offset if known. Otherwise, a dash is printed.
1414 Notice how each question mark has a matching period, and how the %
1415 after the %pt is included literally by escaping it with a backslash.
1417 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1419 This prints the filename if this is the first prompt in a file, fol-
1420 lowed by the "file N of N" message if there is more than one input
1421 file. Then, if we are at end-of-file, the string "(END)" is printed
1422 followed by the name of the next file, if there is one. Finally, any
1423 trailing spaces are truncated. This is the default prompt. For refer-
1424 ence, here are the defaults for the other two prompts (-m and -M
1425 respectively). Each is broken into two lines here for readability
1428 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1429 ?pB%pB\%:byte %bB?s/%s...%t
1431 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1432 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1434 And here is the default message produced by the = command:
1436 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1437 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1439 The prompt expansion features are also used for another purpose: if an
1440 environment variable LESSEDIT is defined, it is used as the command to
1441 be executed when the v command is invoked. The LESSEDIT string is
1442 expanded in the same way as the prompt strings. The default value for
1447 Note that this expands to the editor name, followed by a + and the line
1448 number, followed by the file name. If your editor does not accept the
1449 "+linenumber" syntax, or has other differences in invocation syntax,
1450 the LESSEDIT variable can be changed to modify this default.
1454 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1455 "secure" mode. This means these features are disabled:
1461 :e the examine command.
1463 v the editing command
1467 -k use of lesskey files
1469 -t use of tags files
1471 metacharacters in filenames, such as *
1473 filename completion (TAB, ^L)
1475 Less can also be compiled to be permanently in "secure" mode.
1478 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1479 If the environment variable LESS_IS_MORE is set to 1, or if the program
1480 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1481 formance with the POSIX "more" command specification. In this mode,
1482 less behaves differently in these ways:
1484 The -e option works differently. If the -e option is not set,
\e[4mless
\e[0m
1485 behaves as if the -e option were set. If the -e option is set,
\e[4mless
\e[0m
1486 behaves as if the -E option were set.
1488 The -m option works differently. If the -m option is not set, the
1489 medium prompt is used, and it is prefixed with the string "--More--".
1490 If the -m option is set, the short prompt is used.
1492 The -n option acts like the -z option. The normal behavior of the -n
1493 option is unavailable in this mode.
1495 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1496 than a search pattern.
1498 The LESS environment variable is ignored, and the MORE environment
1499 variable is used in its place.
1502 \e[1mENVIRONMENT VARIABLES
\e[0m
1503 Environment variables may be specified either in the system environment
1504 as usual, or in a
\e[4mlesskey
\e[24m (1) file. If environment variables are
1505 defined in more than one place, variables defined in a local lesskey
1506 file take precedence over variables defined in the system environment,
1507 which take precedence over variables defined in the system-wide lesskey
1511 Sets the number of columns on the screen. Takes precedence over
1512 the number of columns specified by the TERM variable. (But if
1513 you have a windowing system which supports TIOCGWINSZ or
1514 WIOCGETD, the window system's idea of the screen size takes
1515 precedence over the LINES and COLUMNS environment variables.)
1517 EDITOR The name of the editor (used for the v command).
1519 HOME Name of the user's home directory (used to find a lesskey file
1520 on Unix and OS/2 systems).
1523 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1524 ables is the name of the user's home directory if the HOME vari-
1525 able is not set (only in the Windows version).
1527 INIT Name of the user's init directory (used to find a lesskey file
1530 LANG Language for determining the character set.
1533 Language for determining the character set.
1535 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1538 Characters which may end an ANSI color escape sequence (default
1542 Characters which may appear between the ESC character and the
1543 end character in an ANSI color escape sequence (default
1544 "0123456789:;[?!"'#%()*+ ".
1547 Format for displaying non-printable, non-control characters.
1550 Defines a character set.
1553 Selects a predefined character set.
1556 Command line to invoke the (optional) input-postprocessor.
1559 Name of the lessecho program (default "lessecho"). The lessecho
1560 program is needed to expand metacharacters, such as * and ?, in
1561 filenames on Unix systems.
1564 Editor prototype string (used for the v command). See discus-
1568 Name of the command used by the -t option to find global tags.
1569 Normally should be set to "global" if your system has the
\e[4mglobal
\e[0m
1570 (1) command. If not set, global tags are not used.
1573 Name of the history file used to remember search commands and
1574 shell commands between invocations of
\e[4mless
\e[24m. If set to "-" or
1575 "/dev/null", a history file is not used. The default is
1576 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1577 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1581 The maximum number of commands to save in the history file. The
1585 Name of the default lesskey(1) file.
1588 Name of the default system-wide lesskey(1) file.
1591 List of characters which are considered "metacharacters" by the
1595 Prefix which less will add before each metacharacter in a com-
1596 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1597 commands containing metacharacters will not be passed to the
1601 Command line to invoke the (optional) input-preprocessor.
1604 Runs less in "secure" mode. See discussion under SECURITY.
1607 String to be appended to a directory name in filename comple-
1611 Format for displaying non-printable Unicode code points.
1614 Emulate the
\e[4mmore
\e[24m (1) command.
1616 LINES Sets the number of lines on the screen. Takes precedence over
1617 the number of lines specified by the TERM variable. (But if you
1618 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1619 the window system's idea of the screen size takes precedence
1620 over the LINES and COLUMNS environment variables.)
1622 MORE Options which are passed to
\e[4mless
\e[24m automatically when running in
1623 \e[4mmore
\e[24m compatible mode.
1625 PATH User's search path (used to find a lesskey file on MS-DOS and
1628 SHELL The shell used to execute the ! command, as well as to expand
1631 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1633 VISUAL The name of the editor (used for the v command).
1641 Copyright (C) 1984-2017 Mark Nudelman
1643 less is part of the GNU project and is free software. You can redis-
1644 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1645 eral Public License as published by the Free Software Foundation; or
1646 (2) the Less License. See the file README in the less distribution for
1647 more details regarding redistribution. You should have received a copy
1648 of the GNU General Public License along with the source for less; see
1649 the file COPYING. If not, write to the Free Software Foundation, 59
1650 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1651 have received a copy of the Less License; see the file LICENSE.
1653 less is distributed in the hope that it will be useful, but WITHOUT ANY
1654 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1655 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1661 Send bug reports or comments to <bug-less@gnu.org>
1662 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1663 of known bugs in less.
1664 For more information, see the less homepage at
1665 http://www.greenwoodsoftware.com/less.
1669 Version 530: 05 Dec 2017 LESS(1)
projects / platform / upstream / less.git / blob