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
22 \e[4mLess
\e[24m is a program similar to
\e[4mmore
\e[24m(1), but which allows backward move-
23 ment in the file as well as forward movement. Also,
\e[4mless
\e[24m does not have
24 to read the entire input file before starting, so with large input
25 files it starts up faster than text editors like
\e[4mvi
\e[24m(1).
\e[4mLess
\e[24m uses
26 termcap (or terminfo on some systems), so it can run on a variety of
27 terminals. There is even limited support for hardcopy terminals. (On
28 a hardcopy terminal, lines which should be printed at the top of the
29 screen are prefixed with a caret.)
31 Commands are based on both
\e[4mmore
\e[24m and
\e[4mvi
\e[24m. Commands may be preceded by a
32 decimal number, called N in the descriptions below. The number is used
33 by some commands, as indicated.
36 In the following descriptions, ^X means control-X. ESC stands for the
37 ESCAPE key; for example ESC-v means the two character sequence "ES-
40 h or H Help: display a summary of these commands. If you forget all
41 the other commands, remember this one.
43 SPACE or ^V or f or ^F
44 Scroll forward N lines, default one window (see option -z be-
45 low). If N is more than the screen size, only the final screen-
46 ful is displayed. Warning: some systems use ^V as a special
47 literalization character.
49 z Like SPACE, but if N is specified, it becomes the new window
53 Like SPACE, but scrolls a full screenful, even if it reaches
54 end-of-file in the process.
56 ENTER or RETURN or ^N or e or ^E or j or ^J
57 Scroll forward N lines, default 1. The entire N lines are dis-
58 played, even if N is more than the screen size.
61 Scroll forward N lines, default one half of the screen size. If
62 N is specified, it becomes the new default for subsequent d and
66 Scroll backward N lines, default one window (see option -z be-
67 low). If N is more than the screen size, only the final screen-
70 w Like ESC-v, but if N is specified, it becomes the new window
73 y or ^Y or ^P or k or ^K
74 Scroll backward N lines, default 1. The entire N lines are dis-
75 played, even if N is more than the screen size. Warning: some
76 systems use ^Y as a special job control character.
79 Scroll backward N lines, default one half of the screen size.
80 If N is specified, it becomes the new default for subsequent d
83 J Like j, but continues to scroll beyond the end of the file.
85 K or Y Like k, but continues to scroll beyond the beginning of the
89 Scroll horizontally right N characters, default half the screen
90 width (see the -# option). If a number N is specified, it be-
91 comes the default for future RIGHTARROW and LEFTARROW commands.
92 While the text is scrolled, it acts as though the -S option
93 (chop lines) were in effect.
96 Scroll horizontally left N characters, default half the screen
97 width (see the -# option). If a number N is specified, it be-
98 comes the default for future RIGHTARROW and LEFTARROW commands.
101 Scroll horizontally right to show the end of the longest dis-
105 Scroll horizontally left back to the first column.
110 R Repaint the screen, discarding any buffered input. That is,
111 reload the current file. Useful if the file is changing while
114 F Scroll forward, and keep trying to read when the end of file is
115 reached. Normally this command would be used when already at
116 the end of the file. It is a way to monitor the tail of a file
117 which is growing while it is being viewed. (The behavior is
118 similar to the "tail -f" command.) To stop waiting for more
119 data, enter the interrupt character (usually ^C). On some sys-
120 tems you can also use ^X. If the input is a pipe and the
121 --exit-follow-on-close option is in effect,
\e[4mless
\e[24m will automati-
122 cally stop waiting for data when the input side of the pipe is
125 ESC-F Like F, but as soon as a line is found which matches the last
126 search pattern, the terminal bell is rung and forward scrolling
130 Go to line N in the file, default 1 (beginning of file). (Warn-
131 ing: this may be slow if N is large.)
134 Go to line N in the file, default the end of the file. (Warn-
135 ing: this may be slow if N is large, or if N is not specified
136 and standard input, rather than a file, is being read.)
138 ESC-G Same as G, except if no number N is specified and the input is
139 standard input, goes to the last line which is currently
142 p or % Go to a position N percent into the file. N should be between 0
143 and 100, and may contain a decimal point.
145 P Go to the line containing byte offset N in the file.
147 { If a left curly bracket appears in the top line displayed on the
148 screen, the { command will go to the matching right curly
149 bracket. The matching right curly bracket is positioned on the
150 bottom line of the screen. If there is more than one left curly
151 bracket on the top line, a number N may be used to specify the
152 N-th bracket on the line.
154 } If a right curly bracket appears in the bottom line displayed on
155 the screen, the } command will go to the matching left curly
156 bracket. The matching left curly bracket is positioned on the
157 top line of the screen. If there is more than one right curly
158 bracket on the bottom line, a number N may be used to specify
159 the N-th bracket on the line.
161 ( Like {, but applies to parentheses rather than curly brackets.
163 ) Like }, but applies to parentheses rather than curly brackets.
165 [ Like {, but applies to square brackets rather than curly brack-
168 ] Like }, but applies to square brackets rather than curly brack-
171 ESC-^F Followed by two characters, acts like {, but uses the two char-
172 acters as open and close brackets, respectively. For example,
173 "ESC ^F < >" could be used to go forward to the > which matches
174 the < in the top displayed line.
176 ESC-^B Followed by two characters, acts like }, but uses the two char-
177 acters as open and close brackets, respectively. For example,
178 "ESC ^B < >" could be used to go backward to the < which matches
179 the > in the bottom displayed line.
181 m Followed by any lowercase or uppercase letter, marks the first
182 displayed line with that letter. If the status column is en-
183 abled via the -J option, the status column shows the marked
186 M Acts like m, except the last displayed line is marked rather
187 than the first displayed line.
189 ' (Single quote.) Followed by any lowercase or uppercase letter,
190 returns to the position which was previously marked with that
191 letter. Followed by another single quote, returns to the posi-
192 tion at which the last "large" movement command was executed.
193 Followed by a ^ or $, jumps to the beginning or end of the file
194 respectively. Marks are preserved when a new file is examined,
195 so the ' command can be used to switch between input files.
197 ^X^X Same as single quote.
199 ESC-m Followed by any lowercase or uppercase letter, clears the mark
200 identified by that letter.
203 Search forward in the file for the N-th line containing the pat-
204 tern. N defaults to 1. The pattern is a regular expression, as
205 recognized by the regular expression library supplied by your
206 system. The search starts at the first line displayed (but see
207 the -a and -j options, which change this).
209 Certain characters are special if entered at the beginning of
210 the pattern; they modify the type of search rather than become
214 Search for lines which do NOT match the pattern.
217 Search multiple files. That is, if the search reaches
218 the END of the current file without finding a match, the
219 search continues in the next file in the command line
223 Begin the search at the first line of the FIRST file in
224 the command line list, regardless of what is currently
225 displayed on the screen or the settings of the -a or -j
228 ^K Highlight any text which matches the pattern on the cur-
229 rent screen, but don't move to the first match (KEEP cur-
232 ^R Don't interpret regular expression metacharacters; that
233 is, do a simple textual comparison.
235 ^W WRAP around the current file. That is, if the search
236 reaches the end of the current file without finding a
237 match, the search continues from the first line of the
238 current file up to the line where it started. If the ^W
239 modifier is set, the ^E modifier is ignored.
242 Search backward in the file for the N-th line containing the
243 pattern. The search starts at the last line displayed (but see
244 the -a and -j options, which change this).
246 Certain characters are special as in the / command:
249 Search for lines which do NOT match the pattern.
252 Search multiple files. That is, if the search reaches
253 the beginning of the current file without finding a
254 match, the search continues in the previous file in the
258 Begin the search at the last line of the last file in the
259 command line list, regardless of what is currently dis-
260 played on the screen or the settings of the -a or -j op-
263 ^K As in forward searches.
265 ^R As in forward searches.
267 ^W WRAP around the current file. That is, if the search
268 reaches the beginning of the current file without finding
269 a match, the search continues from the last line of the
270 current file up to the line where it started.
278 n Repeat previous search, for N-th line containing the last pat-
279 tern. If the previous search was modified by ^N, the search is
280 made for the N-th line NOT containing the pattern. If the pre-
281 vious search was modified by ^E, the search continues in the
282 next (or previous) file if not satisfied in the current file.
283 If the previous search was modified by ^R, the search is done
284 without using regular expressions. There is no effect if the
285 previous search was modified by ^F or ^K.
287 N Repeat previous search, but in the reverse direction.
289 ESC-n Repeat previous search, but crossing file boundaries. The ef-
290 fect is as if the previous search were modified by *.
292 ESC-N Repeat previous search, but in the reverse direction and cross-
295 ESC-u Undo search highlighting. Turn off highlighting of strings
296 matching the current search pattern. If highlighting is already
297 off because of a previous ESC-u command, turn highlighting back
298 on. Any search command will also turn highlighting back on.
299 (Highlighting can also be disabled by toggling the -G option; in
300 that case search commands do not turn highlighting back on.)
302 ESC-U Like ESC-u but also clears the saved search pattern. If the
303 status column is enabled via the -J option, this clears all
304 search matches marked in the status column.
307 Display only lines which match the pattern; lines which do not
308 match the pattern are not displayed. If pattern is empty (if
309 you type & immediately followed by ENTER), any filtering is
310 turned off, and all lines are displayed. While filtering is in
311 effect, an ampersand is displayed at the beginning of the
312 prompt, as a reminder that some lines in the file may be hidden.
313 Multiple & commands may be entered, in which case only lines
314 which match all of the patterns will be displayed.
316 Certain characters are special as in the / command:
319 Display only lines which do NOT match the pattern.
321 ^R Don't interpret regular expression metacharacters; that
322 is, do a simple textual comparison.
325 Examine a new file. If the filename is missing, the "current"
326 file (see the :n and :p commands below) from the list of files
327 in the command line is re-examined. A percent sign (%) in the
328 filename is replaced by the name of the current file. A pound
329 sign (#) is replaced by the name of the previously examined
330 file. However, two consecutive percent signs are simply re-
331 placed with a single percent sign. This allows you to enter a
332 filename that contains a percent sign in the name. Similarly,
333 two consecutive pound signs are replaced with a single pound
334 sign. The filename is inserted into the command line list of
335 files so that it can be seen by subsequent :n and :p commands.
336 If the filename consists of several files, they are all inserted
337 into the list of files and the first one is examined. If the
338 filename contains one or more spaces, the entire filename should
339 be enclosed in double quotes (also see the -" option).
342 Same as :e. Warning: some systems use ^V as a special literal-
343 ization character. On such systems, you may not be able to use
346 :n Examine the next file (from the list of files given in the com-
347 mand line). If a number N is specified, the N-th next file is
350 :p Examine the previous file in the command line list. If a number
351 N is specified, the N-th previous file is examined.
353 :x Examine the first file in the command line list. If a number N
354 is specified, the N-th file in the list is examined.
356 :d Remove the current file from the list of files.
358 t Go to the next tag, if there were more than one matches for the
359 current tag. See the -t option for more details about tags.
361 T Go to the previous tag, if there were more than one matches for
365 Prints some information about the file being viewed, including
366 its name and the line number and byte offset of the bottom line
367 being displayed. If possible, it also prints the length of the
368 file, the number of lines in the file and the percent of the
369 file above the last displayed line.
371 - Followed by one of the command line option letters (see OPTIONS
372 below), this will change the setting of that option and print a
373 message describing the new setting. If a ^P (CONTROL-P) is en-
374 tered immediately after the dash, the setting of the option is
375 changed but no message is printed. If the option letter has a
376 numeric value (such as -b or -h), or a string value (such as -P
377 or -t), a new value may be entered after the option letter. If
378 no new value is entered, a message describing the current set-
379 ting is printed and nothing is changed.
381 -- Like the - command, but takes a long option name (see OPTIONS
382 below) rather than a single option letter. You must press ENTER
383 or RETURN after typing the option name. A ^P immediately after
384 the second dash suppresses printing of a message describing the
385 new setting, as in the - command.
387 -+ Followed by one of the command line option letters this will re-
388 set the option to its default setting and print a message de-
389 scribing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
390 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
391 string-valued options.
393 --+ Like the -+ command, but takes a long option name rather than a
394 single option letter.
396 -! Followed by one of the command line option letters, this will
397 reset the option to the "opposite" of its default setting and
398 print a message describing the new setting. This does not work
399 for numeric or string-valued options.
401 --! Like the -! command, but takes a long option name rather than a
402 single option letter.
404 _ (Underscore.) Followed by one of the command line option let-
405 ters, this will print a message describing the current setting
406 of that option. The setting of the option is not changed.
408 __ (Double underscore.) Like the _ (underscore) command, but takes
409 a long option name rather than a single option letter. You must
410 press ENTER or RETURN after typing the option name.
412 +cmd Causes the specified cmd to be executed each time a new file is
413 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
414 file starting at the end rather than the beginning.
416 V Prints the version number of
\e[4mless
\e[24m being run.
418 q or Q or :q or :Q or ZZ
419 Exits
\e[4mless
\e[24m.
421 The following four commands may or may not be valid, depending on your
422 particular installation.
424 v Invokes an editor to edit the current file being viewed. The
425 editor is taken from the environment variable VISUAL if defined,
426 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
427 ther VISUAL nor EDITOR is defined. See also the discussion of
428 LESSEDIT under the section on PROMPTS below.
431 Invokes a shell to run the shell-command given. A percent sign
432 (%) in the command is replaced by the name of the current file.
433 A pound sign (#) is replaced by the name of the previously exam-
434 ined file. "!!" repeats the last shell command. "!" with no
435 shell command simply invokes a shell. On Unix systems, the
436 shell is taken from the environment variable SHELL, or defaults
437 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
441 <m> represents any mark letter. Pipes a section of the input
442 file to the given shell command. The section of the file to be
443 piped is between the position marked by the letter and the cur-
444 rent screen. The entire current screen is included, regardless
445 of whether the marked position is before or after the current
446 screen. <m> may also be ^ or $ to indicate beginning or end of
447 file respectively. If <m> is . or newline, the current screen
451 Save the input to a file. This only works if the input is a
452 pipe, not an ordinary file.
455 Command line options are described below. Most options may be changed
456 while
\e[4mless
\e[24m is running, via the "-" command.
458 Most options may be given in one of two forms: either a dash followed
459 by a single letter, or two dashes followed by a long option name. A
460 long option name may be abbreviated as long as the abbreviation is un-
461 ambiguous. For example, --quit-at-eof may be abbreviated --quit, but
462 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
463 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
464 from --quit-at-eof. Such option names need only have their first let-
465 ter capitalized; the remainder of the name may be in either case. For
466 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
468 Options are also taken from the environment variable "LESS". For exam-
469 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
470 might tell
\e[4mcsh
\e[24m:
472 setenv LESS "-options"
474 or if you use
\e[4msh
\e[24m:
476 LESS="-options"; export LESS
478 On MS-DOS, you don't need the quotes, but you should replace any per-
479 cent signs in the options string by double percent signs.
481 The environment variable is parsed before the command line, so command
482 line options override the LESS environment variable. If an option ap-
483 pears in the LESS variable, it can be reset to its default value on the
484 command line by beginning the command line option with "-+".
486 Some options like -k or -D require a string to follow the option let-
487 ter. The string for that option is considered to end when a dollar
488 sign ($) is found. For example, you can set two -D options on MS-DOS
493 If the --use-backslash option appears earlier in the options, then a
494 dollar sign or backslash may be included literally in an option string
495 by preceding it with a backslash. If the --use-backslash option is not
496 in effect, then backslashes are not treated specially, and there is no
497 way to include a dollar sign in the option string.
500 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
501 (the same as the h command). (Depending on how your shell in-
502 terprets the question mark, it may be necessary to quote the
503 question mark, thus: "-\?".)
505 -a or --search-skip-screen
506 By default, forward searches start at the top of the displayed
507 screen and backwards searches start at the bottom of the dis-
508 played screen (except for repeated searches invoked by the n or
509 N commands, which start after or before the "target" line re-
510 spectively; see the -j option for more about the target line).
511 The -a option causes forward searches to instead start at the
512 bottom of the screen and backward searches to start at the top
513 of the screen, thus skipping all lines displayed on the screen.
515 -A or --SEARCH-SKIP-SCREEN
516 Causes all forward searches (not just non-repeated searches) to
517 start just after the target line, and all backward searches to
518 start just before the target line. Thus, forward searches will
519 skip part of the displayed screen (from the first line up to and
520 including the target line). Similarly backwards searches will
521 skip the displayed screen from the last line up to and including
522 the target line. This was the default behavior in less versions
525 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
526 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
527 file, in units of kilobytes (1024 bytes). By default 64 KB of
528 buffer space is used for each file (unless the file is a pipe;
529 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
530 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
531 -1, buffer space is unlimited; that is, the entire file can be
535 By default, when data is read from a pipe, buffers are allocated
536 automatically as needed. If a large amount of data is read from
537 the pipe, this can cause a large amount of memory to be allo-
538 cated. The -B option disables this automatic allocation of buf-
539 fers for pipes, so that only 64 KB (or the amount of space spec-
540 ified by the -b option) is used for the pipe. Warning: use of
541 -B can result in erroneous display, since only the most recently
542 viewed part of the piped data is kept in memory; any earlier
546 Causes full screen repaints to be painted from the top line
547 down. By default, full screen repaints are done by scrolling
548 from the bottom of the screen.
551 Same as -c, for compatibility with older versions of
\e[4mless
\e[24m.
554 The -d option suppresses the error message normally displayed if
555 the terminal is dumb; that is, lacks some important capability,
556 such as the ability to clear the screen or scroll backward. The
557 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
560 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
561 Changes the color of different parts of the displayed text.
\e[1mx
\e[0m
562 is a single character which selects the type of text whose color
567 C Control characters.
569 E Errors and informational messages.
571 H Header lines and columns, set via the --header option.
573 M Mark letters in the status column.
575 N Line numbers enabled via the -N option.
579 R The rscroll character.
583 W The highlight enabled via the -w option.
593 The uppercase letters can be used only when the --use-color op-
594 tion is enabled. When text color is specified by both an upper-
595 case letter and a lowercase letter, the uppercase letter takes
596 precedence. For example, error messages are normally displayed
597 as standout text. So if both "s" and "E" are given a color, the
598 "E" color applies to error messages, and the "s" color applies
599 to other standout text. The "d" and "u" letters refer to bold
600 and underline text formed by overstriking with backspaces (see
601 the -u option), not to text using ANSI escape sequences with the
604 A lowercase letter may be followed by a + to indicate that the
605 normal format change and the specified color should both be
606 used. For example, -Dug displays underlined text as green with-
607 out underlining; the green color has replaced the usual under-
608 line formatting. But -Du+g displays underlined text as both
609 green and in underlined format.
611 \e[4mcolor
\e[24m is either a 4-bit color string or an 8-bit color string:
613 A 4-bit color string is zero, one or two characters, where the
614 first character specifies the foreground color and the second
615 specifies the background color as follows:
633 The corresponding upper-case letter denotes a brighter shade of
634 the color. For example, -DNGk displays line numbers as bright
635 green text on a black background, and -DEbR displays error mes-
636 sages as blue text on a bright red background. If either char-
637 acter is a "-" or is omitted, the corresponding color is set to
640 An 8-bit color string is one or two decimal integers separated
641 by a dot, where the first integer specifies the foreground color
642 and the second specifies the background color. Each integer is
643 a value between 0 and 255 inclusive which selects a "CSI 38;5"
645 https://en.wikipedia.org/wiki/ANSI_escape_code#SGR) If either
646 integer is a "-" or is omitted, the corresponding color is set
647 to that of normal text. On MS-DOS versions of
\e[4mless
\e[24m, 8-bit color
648 is not supported; instead, decimal values are interpreted as
649 4-bit CHAR_INFO.Attributes values (see
650 https://docs.microsoft.com/en-us/windows/console/char-info-str).
653 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
654 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
658 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
662 Forces non-regular files to be opened. (A non-regular file is a
663 directory or a device special file.) Also suppresses the warn-
664 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
665 refuse to open non-regular files. Note that some operating sys-
666 tems will not allow directories to be read, even if -f is set.
668 -F or --quit-if-one-screen
669 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
670 played on the first screen.
672 -g or --hilite-search
673 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
674 search command. The -g option changes this behavior to high-
675 light only the particular string which was found by the last
676 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
679 -G or --HILITE-SEARCH
680 The -G option suppresses all highlighting of strings found by
683 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
684 Specifies a maximum number of lines to scroll backward. If it
685 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
686 repainted in a forward direction instead. (If the terminal does
687 not have the ability to scroll backward, -h0 is implied.)
690 Causes searches to ignore case; that is, uppercase and lowercase
691 are considered identical. This option is ignored if any upper-
692 case letters appear in the search pattern; in other words, if a
693 pattern contains uppercase letters, then that search does not
697 Like -i, but searches ignore case even if the pattern contains
700 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
701 Specifies a line on the screen where the "target" line is to be
702 positioned. The target line is the line specified by any com-
703 mand to search for a pattern, jump to a line number, jump to a
704 file percentage or jump to a tag. The screen line may be speci-
705 fied by a number: the top line on the screen is 1, the next is
706 2, and so on. The number may be negative to specify a line rel-
707 ative to the bottom of the screen: the bottom line on the screen
708 is -1, the second to the bottom is -2, and so on. Alternately,
709 the screen line may be specified as a fraction of the height of
710 the screen, starting with a decimal point: .5 is in the middle
711 of the screen, .3 is three tenths down from the first line, and
712 so on. If the line is specified as a fraction, the actual line
713 number is recalculated if the terminal window is resized, so
714 that the target line remains at the specified fraction of the
715 screen height. If any form of the -j option is used, repeated
716 forward searches (invoked with "n" or "N") begin at the line im-
717 mediately after the target line, and repeated backward searches
718 begin at the target line, unless changed by -a or -A. For exam-
719 ple, if "-j4" is used, the target line is the fourth line on the
720 screen, so forward searches begin at the fifth line on the
721 screen. However nonrepeated searches (invoked with "/" or "?")
722 always begin at the start or end of the current screen respec-
725 -J or --status-column
726 Displays a status column at the left edge of the screen. The
727 status column shows the lines that matched the current search,
728 and any lines that are marked (via the m or M command).
730 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
731 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[24m(1)
732 binary file. Multiple -k options may be specified. If the
733 LESSKEY or LESSKEY_SYSTEM environment variable is set, or if a
734 lesskey file is found in a standard place (see KEY BINDINGS), it
735 is also used as a
\e[4mlesskey
\e[24m file.
737 --lesskey-src=
\e[4mfilename
\e[0m
738 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[24m(1)
739 source file. If the LESSKEYIN or LESSKEYIN_SYSTEM environment
740 variable is set, or if a lesskey source file is found in a stan-
741 dard place (see KEY BINDINGS), it is also used as a
\e[4mlesskey
\e[0m
742 \e[4msource
\e[24m file. Prior to version 582, the
\e[4mlesskey
\e[24m program needed
743 to be run to convert a
\e[4mlesskey
\e[24m
\e[4msource
\e[24m file to a
\e[4mlesskey
\e[24m
\e[4mbinary
\e[0m
744 file for
\e[4mless
\e[24m to use. Newer versions of
\e[4mless
\e[24m read the
\e[4mlesskey
\e[0m
745 \e[4msource
\e[24m file directly and ignore the binary file if the source
749 Causes
\e[4mless
\e[24m to exit immediately (with status 2) when an inter-
750 rupt character (usually ^C) is typed. Normally, an interrupt
751 character causes
\e[4mless
\e[24m to stop whatever it is doing and return to
752 its command prompt. Note that use of this option makes it im-
753 possible to return to the command prompt from the "F" command.
756 Ignore the LESSOPEN environment variable (see the INPUT PRE-
757 PROCESSOR section below). This option can be set from within
758 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
759 to the file which is currently open.
762 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
763 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
766 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore
\e[24m.
769 Suppresses line numbers. The default (to use line numbers) may
770 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
771 very large input file. Suppressing line numbers with the -n op-
772 tion will avoid this problem. Using line numbers means: the
773 line number will be displayed in the verbose prompt and in the =
774 command, and the v command will pass the current line number to
775 the editor (see also the discussion of LESSEDIT in PROMPTS be-
779 Causes a line number to be displayed at the beginning of each
782 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
783 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
784 viewed. This applies only when the input file is a pipe, not an
785 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
786 confirmation before overwriting it.
788 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
789 The -O option is like -o, but it will overwrite an existing file
790 without asking for confirmation.
792 If no log file has been specified, the -o and -O options can be
793 used from within
\e[4mless
\e[24m to specify a log file. Without a file
794 name, they will simply report the name of the log file. The "s"
795 command is equivalent to specifying -o from within
\e[4mless
\e[24m.
797 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
798 The -p option on the command line is equivalent to specifying
799 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
800 rence of
\e[4mpattern
\e[24m in the file.
802 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
803 Provides a way to tailor the three prompt styles to your own
804 preference. This option would normally be put in the LESS envi-
805 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
806 mand. Such an option must either be the last option in the LESS
807 variable, or be terminated by a dollar sign.
808 -Ps followed by a string changes the default (short) prompt to
810 -Pm changes the medium (-m) prompt.
811 -PM changes the long (-M) prompt.
812 -Ph changes the prompt for the help screen.
813 -P= changes the message printed by the = command.
814 -Pw changes the message printed while waiting for data (in the
817 All prompt strings consist of a sequence of letters and special
818 escape sequences. See the section on PROMPTS for more details.
820 -q or --quiet or --silent
821 Causes moderately "quiet" operation: the terminal bell is not
822 rung if an attempt is made to scroll past the end of the file or
823 before the beginning of the file. If the terminal has a "visual
824 bell", it is used instead. The bell will be rung on certain
825 other errors, such as typing an invalid character. The default
826 is to ring the terminal bell in all such cases.
828 -Q or --QUIET or --SILENT
829 Causes totally "quiet" operation: the terminal bell is never
830 rung. If the terminal has a "visual bell", it is used in all
831 cases where the terminal bell would have been rung.
833 -r or --raw-control-chars
834 Causes "raw" control characters to be displayed. The default is
835 to display control characters using the caret notation; for ex-
836 ample, a control-A (octal 001) is displayed as "^A". Warning:
837 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
838 appearance of the screen (since this depends on how the screen
839 responds to each type of control character). Thus, various dis-
840 play problems may result, such as long lines being split in the
843 USE OF THE -r OPTION IS NOT RECOMMENDED.
845 -R or --RAW-CONTROL-CHARS
846 Like -r, but only ANSI "color" escape sequences and OSC 8 hyper-
847 link sequences are output in "raw" form. Unlike -r, the screen
848 appearance is maintained correctly, provided that there are no
849 escape sequences in the file other than these types of escape
850 sequences. Color escape sequences are only supported when the
851 color is changed within one line, not across lines. In other
852 words, the beginning of each line is assumed to be normal (non-
853 colored), regardless of any escape sequences in previous lines.
854 For the purpose of keeping track of screen appearance, these es-
855 cape sequences are assumed to not move the cursor.
857 OSC 8 hyperlinks are sequences of the form:
861 The terminating sequence may be either a BEL character (\7) or
862 the two-character sequence "ESC \".
864 ANSI color escape sequences are sequences of the form:
868 where the "..." is zero or more color specification characters.
869 You can make
\e[4mless
\e[24m think that characters other than "m" can end
870 ANSI color escape sequences by setting the environment variable
871 LESSANSIENDCHARS to the list of characters which can end a color
872 escape sequence. And you can make
\e[4mless
\e[24m think that characters
873 other than the standard ones may appear between the ESC and the
874 m by setting the environment variable LESSANSIMIDCHARS to the
875 list of characters which can appear.
877 -s or --squeeze-blank-lines
878 Causes consecutive blank lines to be squeezed into a single
879 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
881 -S or --chop-long-lines
882 Causes lines longer than the screen width to be chopped (trun-
883 cated) rather than wrapped. That is, the portion of a long line
884 that does not fit in the screen width is not displayed until you
885 press RIGHT-ARROW. The default is to wrap long lines; that is,
886 display the remainder on the next line.
888 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
889 The -t option, followed immediately by a TAG, will edit the file
890 containing that tag. For this to work, tag information must be
891 available; for example, there may be a file in the current di-
892 rectory called "tags", which was previously built by
\e[4mctags
\e[24m(1) or
893 an equivalent command. If the environment variable LESSGLOBALT-
894 AGS is set, it is taken to be the name of a command compatible
895 with
\e[4mglobal
\e[24m(1), and that command is executed to find the tag.
896 (See http://www.gnu.org/software/global/global.html). The -t
897 option may also be specified from within
\e[4mless
\e[24m (using the - com-
898 mand) as a way of examining a new file. The command ":t" is
899 equivalent to specifying -t from within
\e[4mless
\e[24m.
901 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
902 Specifies a tags file to be used instead of "tags".
904 -u or --underline-special
905 Causes backspaces and carriage returns to be treated as print-
906 able characters; that is, they are sent to the terminal when
907 they appear in the input.
909 -U or --UNDERLINE-SPECIAL
910 Causes backspaces, tabs, carriage returns and "formatting char-
911 acters" (as defined by Unicode) to be treated as control charac-
912 ters; that is, they are handled as specified by the -r option.
914 By default, if neither -u nor -U is given, backspaces which ap-
915 pear adjacent to an underscore character are treated specially:
916 the underlined text is displayed using the terminal's hardware
917 underlining capability. Also, backspaces which appear between
918 two identical characters are treated specially: the overstruck
919 text is printed using the terminal's hardware boldface capabili-
920 ty. Other backspaces are deleted, along with the preceding
921 character. Carriage returns immediately followed by a newline
922 are deleted. Other carriage returns are handled as specified by
923 the -r option. Unicode formatting characters, such as the Byte
924 Order Mark, are sent to the terminal. Text which is overstruck
925 or underlined can be searched for if neither -u nor -U is in ef-
929 Displays the version number of
\e[4mless
\e[24m.
931 -w or --hilite-unread
932 Temporarily highlights the first "new" line after a forward
933 movement of a full page. The first "new" line is the line imme-
934 diately following the line previously at the bottom of the
935 screen. Also highlights the target line after a g or p command.
936 The highlight is removed at the next command which causes move-
937 ment. If the --status-line option is in effect, the entire line
938 (the width of the screen) is highlighted. Otherwise, only the
939 text in the line is highlighted, unless the -J option is in ef-
940 fect, in which case only the status column is highlighted.
942 -W or --HILITE-UNREAD
943 Like -w, but temporarily highlights the first new line after any
944 forward movement command larger than one line.
946 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
947 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
948 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
949 specified, tab stops are set at those positions, and then con-
950 tinue with the same spacing as the last two. For example,
951 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The de-
952 fault for
\e[4mn
\e[24m is 8.
955 Disables sending the termcap initialization and deinitialization
956 strings to the terminal. This is sometimes desirable if the
957 deinitialization string does something unnecessary, like clear-
960 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
961 Specifies a maximum number of lines to scroll forward. If it is
962 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is re-
963 painted instead. The -c or -C option may be used to repaint
964 from the top of the screen if desired. By default, any forward
965 movement causes scrolling.
967 -z
\e[4mn
\e[24m or --window=
\e[4mn
\e[24m or -
\e[4mn
\e[0m
968 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The de-
969 fault is one screenful. The z and w commands can also be used
970 to change the window size. The "z" may be omitted for compati-
971 bility with some versions of
\e[4mmore
\e[24m. If the number
\e[4mn
\e[24m is negative,
972 it indicates
\e[4mn
\e[24m lines less than the current screen size. For ex-
973 ample, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling window
974 to 20 lines. If the screen is resized to 40 lines, the
975 scrolling window automatically changes to 36 lines.
977 -"
\e[4mcc
\e[24m or --quotes=
\e[4mcc
\e[0m
978 Changes the filename quoting character. This may be necessary
979 if you are trying to name a file which contains both spaces and
980 quote characters. Followed by a single character, this changes
981 the quote character to that character. Filenames containing a
982 space should then be surrounded by that character rather than by
983 double quotes. Followed by two characters, changes the open
984 quote to the first character, and the close quote to the second
985 character. Filenames containing a space should then be preceded
986 by the open quote character and followed by the close quote
987 character. Note that even after the quote characters are
988 changed, this option remains -" (a dash followed by a double
992 Normally lines after end of file are displayed as a single tilde
993 (~). This option causes lines after end of file to be displayed
997 Specifies the default number of positions to scroll horizontally
998 in the RIGHTARROW and LEFTARROW commands. If the number speci-
999 fied is zero, it sets the default number of positions to one
1000 half of the screen width. Alternately, the number may be speci-
1001 fied as a fraction of the width of the screen, starting with a
1002 decimal point: .5 is half of the screen width, .3 is three
1003 tenths of the screen width, and so on. If the number is speci-
1004 fied as a fraction, the actual number of scroll positions is re-
1005 calculated if the terminal window is resized, so that the actual
1006 scroll remains at the specified fraction of the screen width.
1008 --exit-follow-on-close
1009 When using the "F" command on a pipe,
\e[4mless
\e[24m will automatically
1010 stop waiting for more data when the input side of the pipe is
1014 If --file-size is specified,
\e[4mless
\e[24m will determine the size of the
1015 file immediately after opening the file. Normally this is not
1016 done, because it can be slow if the input file is non-seekable
1017 (such as a pipe) and is large.
1020 Normally, if the input file is renamed while an F command is ex-
1021 ecuting,
\e[4mless
\e[24m will continue to display the contents of the orig-
1022 inal file despite its name change. If --follow-name is speci-
1023 fied, during an F command
\e[4mless
\e[24m will periodically attempt to re-
1024 open the file by name. If the reopen succeeds and the file is a
1025 different file from the original (which means that a new file
1026 has been created with the same name as the original (now re-
1027 named) file),
\e[4mless
\e[24m will display the contents of that new file.
1030 Sets the number of header lines and columns displayed on the
1031 screen. The value may be of the form "N,M" where N and M are
1032 integers, to set the header lines to N and the header columns to
1033 M, or it may be a single integer "N" which sets the header lines
1034 to N and the header columns to zero. When N is nonzero, the
1035 first N lines at the top of the screen are replaced with the
1036 first N lines of the file, regardless of what part of the file
1037 are being viewed. When M is nonzero, the characters displayed
1038 at the beginning of each line are replaced with the first M
1039 characters of the line, even if the rest of the line is scrolled
1040 horizontally. If either N or M is zero,
\e[4mless
\e[24m stops displaying
1041 header lines or columns, respectively. (Note that it may be
1042 necessary to change the setting of the -j option to ensure that
1043 the target line is not obscured by the header line(s).)
1046 Subsequent search commands will be "incremental"; that is,
\e[4mless
\e[0m
1047 will advance to the next line containing the search pattern as
1048 each character of the pattern is typed in.
1051 Sets the minimum width of the line number field when the -N op-
1052 tion is in effect. The default is 7 characters.
1055 Enables mouse input: scrolling the mouse wheel down moves for-
1056 ward in the file, scrolling the mouse wheel up moves backwards
1057 in the file, and clicking the mouse sets the "#" mark to the
1058 line where the mouse is clicked. The number of lines to scroll
1059 when the wheel is moved can be set by the --wheel-lines option.
1060 Mouse input works only on terminals which support X11 mouse re-
1061 porting, and on the Windows version of
\e[4mless
\e[24m.
1064 Like --mouse, except the direction scrolled on mouse wheel move-
1068 Disables sending the keypad initialization and deinitialization
1069 strings to the terminal. This is sometimes useful if the keypad
1070 strings make the numeric keypad behave in an undesirable manner.
1073 This option changes the behavior so that if a search string or
1074 file name is typed in, and the same string is already in the
1075 history list, the existing copy is removed from the history list
1076 before the new one is added. Thus, a given string will appear
1077 only once in the history list. Normally, a string may appear
1081 Header lines (defined via the --header option) are not assigned
1082 line numbers. Line number 1 is assigned to the first line after
1086 This option changes the character used to mark truncated lines.
1087 It may begin with a two-character attribute indicator like LESS-
1088 BINFMT does. If there is no attribute indicator, standout is
1089 used. If set to "-", truncated lines are not marked.
1092 When quitting, after sending the terminal deinitialization
1093 string, redraws the entire last screen. On terminals whose ter-
1094 minal deinitialization string causes the terminal to switch from
1095 an alternate screen, this makes the last screenful of the cur-
1096 rent file remain visible after
\e[4mless
\e[24m has quit.
1099 Save marks in the history file, so marks are retained across
1100 different invocations of
\e[4mless
\e[24m.
1103 Sets default search modifiers. The value is a string of one or
1104 more of the characters E, F, K, N, R or W. Setting any of these
1105 has the same effect as typing that control character at the be-
1106 ginning of every search pattern. For example, setting --search-
1107 options=W is the same as typing ^W at the beginning of every
1108 pattern. The value "-" disables all default search modifiers.
1111 Sets the width of the status column when the -J option is in ef-
1112 fect. The default is 2 characters.
1115 If a line is marked, the entire line (rather than just the sta-
1116 tus column) is highlighted. Also lines highlighted due to the
1117 -w option will have the entire line highlighted. If --use-color
1118 is set, the line is colored rather than highlighted.
1121 This option changes the interpretations of options which follow
1122 this one. After the --use-backslash option, any backslash in an
1123 option string is removed and the following character is taken
1124 literally. This allows a dollar sign to be included in option
1128 Enables colored text in various places. The -D option can be
1129 used to change the colors. Colored text works only if the ter-
1130 minal supports ANSI color escape sequences (as defined in EC-
1132 https://www.ecma-international.org/publications-and-
1133 standards/standards/ecma-48).
1135 --wheel-lines=
\e[4mn
\e[0m
1136 Set the number of lines to scroll when the mouse wheel is
1137 scrolled and the --mouse or --MOUSE option is in effect. The
1140 -- A command line argument of "--" marks the end of option argu-
1141 ments. Any arguments following this are interpreted as file-
1142 names. This can be useful when viewing a file whose name begins
1145 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
1146 option is taken to be an initial command to
\e[4mless
\e[24m. For example,
1147 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
1148 beginning, and +/xyz tells it to start at the first occurrence
1149 of "xyz" in the file. As a special case, +<number> acts like
1150 +<number>g; that is, it starts the display at the specified line
1151 number (however, see the caveat under the "g" command above).
1152 If the option starts with ++, the initial command applies to ev-
1153 ery file being viewed, not just the first one. The + command
1154 described previously may also be used to set (or change) an ini-
1155 tial command for every file.
1157 \e[1mLINE EDITING
\e[0m
1158 When entering a command line at the bottom of the screen (for example,
1159 a filename for the :e command, or the pattern for a search command),
1160 certain keys can be used to manipulate the command line. Most commands
1161 have an alternate form in [ brackets ] which can be used if a key does
1162 not exist on a particular keyboard. (Note that the forms beginning
1163 with ESC do not work in some MS-DOS and Windows systems because ESC is
1164 the line erase character.) Any of these special keys may be entered
1165 literally by preceding it with the "literal" character, either ^V or
1166 ^A. A backslash itself may also be entered literally by entering two
1170 Move the cursor one space to the left.
1172 RIGHTARROW [ ESC-l ]
1173 Move the cursor one space to the right.
1175 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
1176 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
1177 sor one word to the left.
1179 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
1180 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
1181 sor one word to the right.
1184 Move the cursor to the beginning of the line.
1187 Move the cursor to the end of the line.
1190 Delete the character to the left of the cursor, or cancel the
1191 command if the command line is empty.
1194 Delete the character under the cursor.
1196 ^BACKSPACE [ ESC-BACKSPACE ]
1197 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
1198 word to the left of the cursor.
1200 ^DELETE [ ESC-X or ESC-DELETE ]
1201 (That is, CONTROL and DELETE simultaneously.) Delete the word
1205 Retrieve the previous command line. If you first enter some
1206 text and then press UPARROW, it will retrieve the previous com-
1207 mand which begins with that text.
1210 Retrieve the next command line. If you first enter some text
1211 and then press DOWNARROW, it will retrieve the next command
1212 which begins with that text.
1214 TAB Complete the partial filename to the left of the cursor. If it
1215 matches more than one filename, the first match is entered into
1216 the command line. Repeated TABs will cycle thru the other
1217 matching filenames. If the completed filename is a directory, a
1218 "/" is appended to the filename. (On MS-DOS systems, a "\" is
1219 appended.) The environment variable LESSSEPARATOR can be used
1220 to specify a different character to append to a directory name.
1223 Like, TAB, but cycles in the reverse direction thru the matching
1226 ^L Complete the partial filename to the left of the cursor. If it
1227 matches more than one filename, all matches are entered into the
1228 command line (if they fit).
1230 ^U (Unix and OS/2) or ESC (MS-DOS)
1231 Delete the entire command line, or cancel the command if the
1232 command line is empty. If you have changed your line-kill char-
1233 acter in Unix to something other than ^U, that character is used
1236 ^G Delete the entire command line and return to the main prompt.
1238 \e[1mKEY BINDINGS
\e[0m
1239 You may define your own
\e[4mless
\e[24m commands by creating a lesskey source
1240 file. This file specifies a set of command keys and an action associ-
1241 ated with each key. You may also change the line-editing keys (see
1242 LINE EDITING), and to set environment variables. If the environment
1243 variable LESSKEYIN is set,
\e[4mless
\e[24m uses that as the name of the lesskey
1244 source file. Otherwise,
\e[4mless
\e[24m looks in a standard place for the lesskey
1245 source file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey file called
1246 "$XDG_CONFIG_HOME/lesskey" or "$HOME/.config/lesskey" or
1247 "$HOME/.lesskey". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks for a
1248 lesskey file called "$HOME/_lesskey", and if it is not found there,
1249 then looks for a lesskey file called "_lesskey" in any directory speci-
1250 fied in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for
1251 a lesskey file called "$HOME/lesskey.ini", and if it is not found, then
1252 looks for a lesskey file called "lesskey.ini" in any directory speci-
1253 fied in the INIT environment variable, and if it not found there, then
1254 looks for a lesskey file called "lesskey.ini" in any directory speci-
1255 fied in the PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for
1258 A system-wide lesskey source file may also be set up to provide key
1259 bindings. If a key is defined in both a local lesskey file and in the
1260 system-wide file, key bindings in the local file take precedence over
1261 those in the system-wide file. If the environment variable
1262 LESSKEYIN_SYSTEM is set,
\e[4mless
\e[24m uses that as the name of the system-wide
1263 lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard place for the sys-
1264 tem-wide lesskey file: On Unix systems, the system-wide lesskey file is
1265 /usr/local/etc/syslesskey. (However, if
\e[4mless
\e[24m was built with a differ-
1266 ent sysconf directory than /usr/local/etc, that directory is where the
1267 sysless file is found.) On MS-DOS and Windows systems, the system-wide
1268 lesskey file is c:\_syslesskey. On OS/2 systems, the system-wide
1269 lesskey file is c:\syslesskey.ini.
1271 Previous versions of
\e[4mless
\e[24m (before v582) used lesskey files with a bina-
1272 ry format, produced by the
\e[4mlesskey
\e[24m program. It is no longer necessary
1273 to use the
\e[4mlesskey
\e[24m program.
1275 \e[1mINPUT PREPROCESSOR
\e[0m
1276 You may define an "input preprocessor" for
\e[4mless
\e[24m. Before
\e[4mless
\e[24m opens a
1277 file, it first gives your input preprocessor a chance to modify the way
1278 the contents of the file are displayed. An input preprocessor is sim-
1279 ply an executable program (or shell script), which writes the contents
1280 of the file to a different file, called the replacement file. The con-
1281 tents of the replacement file are then displayed in place of the con-
1282 tents of the original file. However, it will appear to the user as if
1283 the original file is opened; that is,
\e[4mless
\e[24m will display the original
1284 filename as the name of the current file.
1286 An input preprocessor receives one command line argument, the original
1287 filename, as entered by the user. It should create the replacement
1288 file, and when finished, print the name of the replacement file to its
1289 standard output. If the input preprocessor does not output a replace-
1290 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
1291 processor is not called when viewing standard input. To set up an in-
1292 put preprocessor, set the LESSOPEN environment variable to a command
1293 line which will invoke your input preprocessor. This command line
1294 should include one occurrence of the string "%s", which will be re-
1295 placed by the filename when the input preprocessor command is invoked.
1297 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
1298 gram, called the input postprocessor, which may perform any desired
1299 clean-up action (such as deleting the replacement file created by
1300 LESSOPEN). This program receives two command line arguments, the orig-
1301 inal filename as entered by the user, and the name of the replacement
1302 file. To set up an input postprocessor, set the LESSCLOSE environment
1303 variable to a command line which will invoke your input postprocessor.
1304 It may include two occurrences of the string "%s"; the first is re-
1305 placed with the original name of the file and the second with the name
1306 of the replacement file, which was output by LESSOPEN.
1308 For example, on many Unix systems, these two scripts will allow you to
1309 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1314 *.Z) TEMPFILE=$(mktemp)
1315 uncompress -c $1 >$TEMPFILE 2>/dev/null
1316 if [ -s $TEMPFILE ]; then
1328 To use these scripts, put them both where they can be executed and set
1329 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1330 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1331 types of compressed files, and so on.
1333 It is also possible to set up an input preprocessor to pipe the file
1334 data directly to
\e[4mless
\e[24m, rather than putting the data into a replacement
1335 file. This avoids the need to decompress the entire file before start-
1336 ing to view it. An input preprocessor that works this way is called an
1337 input pipe. An input pipe, instead of writing the name of a replace-
1338 ment file on its standard output, writes the entire contents of the re-
1339 placement file on its standard output. If the input pipe does not
1340 write any characters on its standard output, then there is no replace-
1341 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1342 pipe, make the first character in the LESSOPEN environment variable a
1343 vertical bar (|) to signify that the input preprocessor is an input
1344 pipe. As with non-pipe input preprocessors, the command string must
1345 contain one occurrence of %s, which is replaced with the filename of
1348 For example, on many Unix systems, this script will work like the pre-
1349 vious example scripts:
1354 *.Z) uncompress -c $1 2>/dev/null
1361 To use this script, put it where it can be executed and set
1362 LESSOPEN="|lesspipe.sh %s".
1364 Note that a preprocessor cannot output an empty file, since that is in-
1365 terpreted as meaning there is no replacement, and the original file is
1366 used. To avoid this, if LESSOPEN starts with two vertical bars, the
1367 exit status of the script determines the behavior when the output is
1368 empty. If the output is empty and the exit status is zero, the empty
1369 output is considered to be replacement text. If the output is empty
1370 and the exit status is nonzero, the original file is used. For compat-
1371 ibility with previous versions of
\e[4mless
\e[24m, if LESSOPEN starts with only
1372 one vertical bar, the exit status of the preprocessor is ignored.
1374 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1375 it is usually not necessary since there is no replacement file to clean
1376 up. In this case, the replacement file name passed to the LESSCLOSE
1377 postprocessor is "-".
1379 For compatibility with previous versions of
\e[4mless
\e[24m, the input preproces-
1380 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1381 the first character of LESSOPEN is a dash (-), the input preprocessor
1382 is used on standard input as well as other files. In this case, the
1383 dash is not considered to be part of the preprocessor command. If
1384 standard input is being viewed, the input preprocessor is passed a file
1385 name consisting of a single dash. Similarly, if the first two charac-
1386 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1387 and a dash (||-), the input pipe is used on standard input as well as
1388 other files. Again, in this case the dash is not considered to be part
1389 of the input pipe command.
1391 \e[1mNATIONAL CHARACTER SETS
\e[0m
1392 There are three types of characters in the input file:
1395 can be displayed directly to the screen.
1398 should not be displayed directly, but are expected to be found
1399 in ordinary text files (such as backspace and tab).
1402 should not be displayed directly and are not expected to be
1403 found in text files.
1405 A "character set" is simply a description of which characters are to be
1406 considered normal, control, and binary. The LESSCHARSET environment
1407 variable may be used to select a character set. Possible values for
1410 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1411 with values between 32 and 126 are normal, and all others are
1415 Selects an ISO 8859 character set. This is the same as ASCII,
1416 except characters between 160 and 255 are treated as normal
1419 latin1 Same as iso8859.
1421 latin9 Same as iso8859.
1423 dos Selects a character set appropriate for MS-DOS.
1425 ebcdic Selects an EBCDIC character set.
1428 Selects an EBCDIC character set used by OS/390 Unix Services.
1429 This is the EBCDIC analogue of latin1. You get similar results
1430 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1433 koi8-r Selects a Russian character set.
1435 next Selects a character set appropriate for NeXT computers.
1437 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1438 UTF-8 is special in that it supports multi-byte characters in
1439 the input file. It is the only character set that supports mul-
1443 Selects a character set appropriate for Microsoft Windows (cp
1446 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1447 other than the ones definable by LESSCHARSET. In this case, the envi-
1448 ronment variable LESSCHARDEF can be used to define a character set. It
1449 should be set to a string where each character in the string represents
1450 one character in the character set. The character "." is used for a
1451 normal character, "c" for control, and "b" for binary. A decimal num-
1452 ber may be used for repetition. For example, "bccc4b." would mean
1453 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are bina-
1454 ry, and 8 is normal. All characters after the last are taken to be the
1455 same as the last, so characters 9 through 255 would be normal. (This
1456 is an example, and does not necessarily represent any real character
1459 This table shows the value of LESSCHARDEF which is equivalent to each
1460 of the possible values for LESSCHARSET:
1462 ascii 8bcccbcc18b95.b
1463 dos 8bcccbcc12bc5b95.b.
1464 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1465 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1466 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1468 iso8859 8bcccbcc18b95.33b.
1469 koi8-r 8bcccbcc18b95.b128.
1470 latin1 8bcccbcc18b95.33b.
1471 next 8bcccbcc18b95.bb125.bb
1473 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1474 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1475 LANG environment variables, then the default character set is utf-8.
1477 If that string is not found, but your system supports the
\e[4msetlocale
\e[24m in-
1478 terface,
\e[4mless
\e[24m will use setlocale to determine the character set. set-
1479 locale is controlled by setting the LANG or LC_CTYPE environment vari-
1482 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1483 character set is latin1.
1485 Control and binary characters are displayed in standout (reverse
1486 video). Each such character is displayed in caret notation if possible
1487 (e.g. ^A for control-A). Caret notation is used only if inverting the
1488 0100 bit results in a normal printable character. Otherwise, the char-
1489 acter is displayed as a hex number in angle brackets. This format can
1490 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1491 may begin with a "*" and one character to select the display attribute:
1492 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1493 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1494 attribute is assumed. The remainder of LESSBINFMT is a string which
1495 may include one printf-style escape sequence (a % followed by x, X, o,
1496 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1497 are displayed in underlined hexadecimal surrounded by brackets. The
1498 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the re-
1499 sult of expanding the character via LESSBINFMT must be less than 31
1502 When the character set is utf-8, the LESSUTFBINFMT environment variable
1503 acts similarly to LESSBINFMT but it applies to Unicode code points that
1504 were successfully decoded but are unsuitable for display (e.g., unas-
1505 signed code points). Its default value is "<U+%04lX>". Note that
1506 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1507 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1508 LESSBINFMT so its setting, if any, will have priority. Problematic
1509 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1510 complete but non-shortest form sequence, invalid octets, and stray
1511 trailing octets) are displayed individually using LESSBINFMT so as to
1512 facilitate diagnostic of how the UTF-8 file is ill-formed.
1515 The -P option allows you to tailor the prompt to your preference. The
1516 string given to the -P option replaces the specified prompt string.
1517 Certain characters in the string are interpreted specially. The prompt
1518 mechanism is rather complicated to provide flexibility, but the ordi-
1519 nary user need not understand the details of constructing personalized
1522 A percent sign followed by a single character is expanded according to
1523 what the following character is:
1525 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1526 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1527 ifies the line whose byte offset is to be used. If the charac-
1528 ter is a "t", the byte offset of the top line in the display is
1529 used, an "m" means use the middle line, a "b" means use the bot-
1530 tom line, a "B" means use the line just after the bottom line,
1531 and a "j" means use the "target" line, as specified by the -j
1534 %B Replaced by the size of the current input file.
1536 %c Replaced by the column number of the text appearing in the first
1537 column of the screen.
1539 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1540 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1542 %D Replaced by the number of pages in the input file, or equiva-
1543 lently, the page number of the last line in the input file.
1545 %E Replaced by the name of the editor (from the VISUAL environment
1546 variable, or the EDITOR environment variable if VISUAL is not
1547 defined). See the discussion of the LESSEDIT feature below.
1549 %f Replaced by the name of the current input file.
1551 %F Replaced by the last component of the name of the current input
1554 %g Replaced by the shell-escaped name of the current input file.
1555 This is useful when the expanded string will be used in a shell
1556 command, such as in LESSEDIT.
1558 %i Replaced by the index of the current file in the list of input
1561 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1562 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1564 %L Replaced by the line number of the last line in the input file.
1566 %m Replaced by the total number of input files.
1568 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1569 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1572 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1573 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1578 %t Causes any trailing spaces to be removed. Usually used at the
1579 end of the string, but may appear anywhere.
1581 %T Normally expands to the word "file". However if viewing files
1582 via a tags list using the -t option, it expands to the word
1585 %x Replaced by the name of the next input file in the list.
1587 If any item is unknown (for example, the file size if input is a pipe),
1588 a question mark is printed instead.
1590 The format of the prompt string can be changed depending on certain
1591 conditions. A question mark followed by a single character acts like
1592 an "IF": depending on the following character, a condition is evaluat-
1593 ed. If the condition is true, any characters following the question
1594 mark and condition character, up to a period, are included in the
1595 prompt. If the condition is false, such characters are not included.
1596 A colon appearing between the question mark and the period can be used
1597 to establish an "ELSE": any characters between the colon and the period
1598 are included in the string if and only if the IF condition is false.
1599 Condition characters (which follow a question mark) may be:
1601 ?a True if any characters have been included in the prompt so far.
1603 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1605 ?B True if the size of current input file is known.
1607 ?c True if the text is horizontally shifted (%c is not zero).
1609 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1611 ?e True if at end-of-file.
1613 ?f True if there is an input filename (that is, if input is not a
1616 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1618 ?L True if the line number of the last line in the file is known.
1620 ?m True if there is more than one input file.
1622 ?n True if this is the first prompt in a new input file.
1624 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1625 offsets, of the specified line is known.
1627 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1628 numbers, of the specified line is known.
1632 ?x True if there is a next input file (that is, if the current in-
1633 put file is not the last one).
1635 Any characters other than the special ones (question mark, colon, peri-
1636 od, percent, and backslash) become literally part of the prompt. Any
1637 of the special characters may be included in the prompt literally by
1638 preceding it with a backslash.
1642 ?f%f:Standard input.
1644 This prompt prints the filename, if known; otherwise the string "Stan-
1647 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1649 This prompt would print the filename, if known. The filename is fol-
1650 lowed by the line number, if known, otherwise the percent if known,
1651 otherwise the byte offset if known. Otherwise, a dash is printed. No-
1652 tice how each question mark has a matching period, and how the % after
1653 the %pt is included literally by escaping it with a backslash.
1655 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1657 This prints the filename if this is the first prompt in a file, fol-
1658 lowed by the "file N of N" message if there is more than one input
1659 file. Then, if we are at end-of-file, the string "(END)" is printed
1660 followed by the name of the next file, if there is one. Finally, any
1661 trailing spaces are truncated. This is the default prompt. For refer-
1662 ence, here are the defaults for the other two prompts (-m and -M re-
1663 spectively). Each is broken into two lines here for readability only.
1665 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1666 ?pB%pB\%:byte %bB?s/%s...%t
1668 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1669 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1671 And here is the default message produced by the = command:
1673 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1674 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1676 The prompt expansion features are also used for another purpose: if an
1677 environment variable LESSEDIT is defined, it is used as the command to
1678 be executed when the v command is invoked. The LESSEDIT string is ex-
1679 panded in the same way as the prompt strings. The default value for
1684 Note that this expands to the editor name, followed by a + and the line
1685 number, followed by the shell-escaped file name. If your editor does
1686 not accept the "+linenumber" syntax, or has other differences in invo-
1687 cation syntax, the LESSEDIT variable can be changed to modify this de-
1691 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1692 "secure" mode. This means these features are disabled:
1698 :e the examine command.
1700 v the editing command
1704 -k use of lesskey files
1706 -t use of tags files
1708 metacharacters in filenames, such as *
1710 filename completion (TAB, ^L)
1714 Less can also be compiled to be permanently in "secure" mode.
1716 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1717 If the environment variable LESS_IS_MORE is set to 1, or if the program
1718 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1719 formance with the POSIX "more" command specification. In this mode,
1720 less behaves differently in these ways:
1722 The -e option works differently. If the -e option is not set,
\e[4mless
\e[24m be-
1723 haves as if the -e option were set. If the -e option is set,
\e[4mless
\e[24m be-
1724 haves as if the -E option were set.
1726 The -m option works differently. If the -m option is not set, the
1727 medium prompt is used, and it is prefixed with the string "--More--".
1728 If the -m option is set, the short prompt is used.
1730 The -n option acts like the -z option. The normal behavior of the -n
1731 option is unavailable in this mode.
1733 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1734 than a search pattern.
1736 The LESS environment variable is ignored, and the MORE environment
1737 variable is used in its place.
1739 \e[1mENVIRONMENT VARIABLES
\e[0m
1740 Environment variables may be specified either in the system environment
1741 as usual, or in a
\e[4mlesskey
\e[24m(1) file. If environment variables are de-
1742 fined in more than one place, variables defined in a local lesskey file
1743 take precedence over variables defined in the system environment, which
1744 take precedence over variables defined in the system-wide lesskey file.
1747 Sets the number of columns on the screen. Takes precedence over
1748 the number of columns specified by the TERM variable. (But if
1749 you have a windowing system which supports TIOCGWINSZ or
1750 WIOCGETD, the window system's idea of the screen size takes
1751 precedence over the LINES and COLUMNS environment variables.)
1753 EDITOR The name of the editor (used for the v command).
1755 HOME Name of the user's home directory (used to find a lesskey file
1756 on Unix and OS/2 systems).
1759 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1760 ables is the name of the user's home directory if the HOME vari-
1761 able is not set (only in the Windows version).
1763 INIT Name of the user's init directory (used to find a lesskey file
1766 LANG Language for determining the character set.
1769 Language for determining the character set.
1771 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1774 Characters which may end an ANSI color escape sequence (default
1778 Characters which may appear between the ESC character and the
1779 end character in an ANSI color escape sequence (default
1780 "0123456789:;[?!"'#%()*+ ".
1783 Format for displaying non-printable, non-control characters.
1786 Defines a character set.
1789 Selects a predefined character set.
1792 Command line to invoke the (optional) input-postprocessor.
1795 Name of the lessecho program (default "lessecho"). The lessecho
1796 program is needed to expand metacharacters, such as * and ?, in
1797 filenames on Unix systems.
1800 Editor prototype string (used for the v command). See discus-
1804 Name of the command used by the -t option to find global tags.
1805 Normally should be set to "global" if your system has the
\e[4mglob-
\e[0m
1806 \e[4mal
\e[24m(1) command. If not set, global tags are not used.
1809 Name of the history file used to remember search commands and
1810 shell commands between invocations of
\e[4mless
\e[24m. If set to "-" or
1811 "/dev/null", a history file is not used. The default is
1812 "$XDG_STATE_HOME/lesshst" or "$HOME/.local/state/lesshst" or
1813 "$XDG_DATA_HOME/lesshst" or "$HOME/.lesshst" on Unix systems,
1814 "$HOME/_lesshst" on DOS and Windows systems, or
1815 "$HOME/lesshst.ini" or "$INIT/lesshst.ini" on OS/2 systems.
1818 The maximum number of commands to save in the history file. The
1822 Name of the default
\e[4mlesskey
\e[24m
\e[4msource
\e[24m file.
1825 Name of the default
\e[4mlesskey
\e[24m
\e[4mbinary
\e[24m file. (Not used if
1826 "$LESSKEYIN" exists.)
1829 Name of the default system-wide
\e[4mlesskey
\e[24m
\e[4msource
\e[24m file.
1832 Name of the default system-wide
\e[4mlesskey
\e[24m
\e[4mbinary
\e[24m file. (Not used
1833 if "$LESSKEYIN_SYSTEM" exists.)
1836 List of characters which are considered "metacharacters" by the
1840 Prefix which less will add before each metacharacter in a com-
1841 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1842 commands containing metacharacters will not be passed to the
1846 Command line to invoke the (optional) input-preprocessor.
1849 Runs less in "secure" mode. See discussion under SECURITY.
1852 String to be appended to a directory name in filename comple-
1856 Format for displaying non-printable Unicode code points.
1859 Emulate the
\e[4mmore
\e[24m(1) command.
1861 LINES Sets the number of lines on the screen. Takes precedence over
1862 the number of lines specified by the TERM variable. (But if you
1863 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1864 the window system's idea of the screen size takes precedence
1865 over the LINES and COLUMNS environment variables.)
1867 MORE Options which are passed to
\e[4mless
\e[24m automatically when running in
1868 \e[4mmore
\e[24m compatible mode.
1870 PATH User's search path (used to find a lesskey file on MS-DOS and
1873 SHELL The shell used to execute the ! command, as well as to expand
1876 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1878 VISUAL The name of the editor (used for the v command).
1881 \e[1mlesskey
\e[22m(1)
1884 Copyright (C) 1984-2022 Mark Nudelman
1886 less is part of the GNU project and is free software. You can redis-
1887 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1888 eral Public License as published by the Free Software Foundation; or
1889 (2) the Less License. See the file README in the less distribution for
1890 more details regarding redistribution. You should have received a copy
1891 of the GNU General Public License along with the source for less; see
1892 the file COPYING. If not, write to the Free Software Foundation, 59
1893 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1894 have received a copy of the Less License; see the file LICENSE.
1896 less is distributed in the hope that it will be useful, but WITHOUT ANY
1897 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1898 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1903 Report bugs at https://github.com/gwsw/less/issues.
1904 For more information, see the less homepage at
1905 https://greenwoodsoftware.com/less
1909 Version 608: 22 Jul 2022 LESS(1)