6 less - opposite of more
12 \e[1mless --version
\e[0m
13 \e[1mless [-[+]aBcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
\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 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
86 Scroll horizontally right N characters, default half the screen
87 width (see the -# option). If a number N is specified, it
88 becomes the default for future RIGHTARROW and LEFTARROW com-
89 mands. While the text is scrolled, it acts as though the -S
90 option (chop lines) were in effect.
93 Scroll horizontally left N characters, default half the screen
94 width (see the -# option). If a number N is specified, it
95 becomes the default for future RIGHTARROW and LEFTARROW com-
101 R Repaint the screen, discarding any buffered input. Useful if
102 the file is changing while it is being viewed.
104 F Scroll forward, and keep trying to read when the end of file is
105 reached. Normally this command would be used when already at
106 the end of the file. It is a way to monitor the tail of a file
107 which is growing while it is being viewed. (The behavior is
108 similar to the "tail -f" command.)
111 Go to line N in the file, default 1 (beginning of file). (Warn-
112 ing: this may be slow if N is large.)
115 Go to line N in the file, default the end of the file. (Warn-
116 ing: this may be slow if N is large, or if N is not specified
117 and standard input, rather than a file, is being read.)
119 p or % Go to a position N percent into the file. N should be between 0
120 and 100, and may contain a decimal point.
122 P Go to the line containing byte offset N in the file.
124 { If a left curly bracket appears in the top line displayed on the
125 screen, the { command will go to the matching right curly
126 bracket. The matching right curly bracket is positioned on the
127 bottom line of the screen. If there is more than one left curly
128 bracket on the top line, a number N may be used to specify the
129 N-th bracket on the line.
131 } If a right curly bracket appears in the bottom line displayed on
132 the screen, the } command will go to the matching left curly
133 bracket. The matching left curly bracket is positioned on the
134 top line of the screen. If there is more than one right curly
135 bracket on the top line, a number N may be used to specify the
136 N-th bracket on the line.
138 ( Like {, but applies to parentheses rather than curly brackets.
140 ) Like }, but applies to parentheses rather than curly brackets.
142 [ Like {, but applies to square brackets rather than curly brack-
145 ] Like }, but applies to square brackets rather than curly brack-
148 ESC-^F Followed by two characters, acts like {, but uses the two char-
149 acters as open and close brackets, respectively. For example,
150 "ESC ^F < >" could be used to go forward to the > which matches
151 the < in the top displayed line.
153 ESC-^B Followed by two characters, acts like }, but uses the two char-
154 acters as open and close brackets, respectively. For example,
155 "ESC ^B < >" could be used to go backward to the < which matches
156 the > in the bottom displayed line.
158 m Followed by any lowercase letter, marks the current position
161 ' (Single quote.) Followed by any lowercase letter, returns to
162 the position which was previously marked with that letter. Fol-
163 lowed by another single quote, returns to the position at which
164 the last "large" movement command was executed. Followed by a ^
165 or $, jumps to the beginning or end of the file respectively.
166 Marks are preserved when a new file is examined, so the ' com-
167 mand can be used to switch between input files.
169 ^X^X Same as single quote.
172 Search forward in the file for the N-th line containing the pat-
173 tern. N defaults to 1. The pattern is a regular expression, as
174 recognized by the regular expression library supplied by your
175 system. The search starts at the second line displayed (but see
176 the -a and -j options, which change this).
178 Certain characters are special if entered at the beginning of
179 the pattern; they modify the type of search rather than become
183 Search for lines which do NOT match the pattern.
186 Search multiple files. That is, if the search reaches
187 the END of the current file without finding a match, the
188 search continues in the next file in the command line
192 Begin the search at the first line of the FIRST file in
193 the command line list, regardless of what is currently
194 displayed on the screen or the settings of the -a or -j
197 ^K Highlight any text which matches the pattern on the cur-
198 rent screen, but don't move to the first match (KEEP cur-
201 ^R Don't interpret regular expression metacharacters; that
202 is, do a simple textual comparison.
205 Search backward in the file for the N-th line containing the
206 pattern. The search starts at the line immediately before the
209 Certain characters are special as in the / command:
212 Search for lines which do NOT match the pattern.
215 Search multiple files. That is, if the search reaches
216 the beginning of the current file without finding a
217 match, the search continues in the previous file in the
221 Begin the search at the last line of the last file in the
222 command line list, regardless of what is currently dis-
223 played on the screen or the settings of the -a or -j
226 ^K As in forward searches.
228 ^R As in forward searches.
236 n Repeat previous search, for N-th line containing the last pat-
237 tern. If the previous search was modified by ^N, the search is
238 made for the N-th line NOT containing the pattern. If the pre-
239 vious search was modified by ^E, the search continues in the
240 next (or previous) file if not satisfied in the current file.
241 If the previous search was modified by ^R, the search is done
242 without using regular expressions. There is no effect if the
243 previous search was modified by ^F or ^K.
245 N Repeat previous search, but in the reverse direction.
247 ESC-n Repeat previous search, but crossing file boundaries. The
248 effect is as if the previous search were modified by *.
250 ESC-N Repeat previous search, but in the reverse direction and cross-
253 ESC-u Undo search highlighting. Turn off highlighting of strings
254 matching the current search pattern. If highlighting is already
255 off because of a previous ESC-u command, turn highlighting back
256 on. Any search command will also turn highlighting back on.
257 (Highlighting can also be disabled by toggling the -G option; in
258 that case search commands do not turn highlighting back on.)
261 Display only lines which match the pattern; lines which do not
262 match the pattern are not displayed. If pattern is empty (if
263 you type & immediately followed by ENTER), any filtering is
264 turned off, and all lines are displayed. While filtering is in
265 effect, an ampersand is displayed at the beginning of the
266 prompt, as a reminder that some lines in the file may be hidden.
268 Certain characters are special as in the / command:
271 Display only lines which do NOT match the pattern.
273 ^R Don't interpret regular expression metacharacters; that
274 is, do a simple textual comparison.
277 Examine a new file. If the filename is missing, the "current"
278 file (see the :n and :p commands below) from the list of files
279 in the command line is re-examined. A percent sign (%) in the
280 filename is replaced by the name of the current file. A pound
281 sign (#) is replaced by the name of the previously examined
282 file. However, two consecutive percent signs are simply
283 replaced with a single percent sign. This allows you to enter a
284 filename that contains a percent sign in the name. Similarly,
285 two consecutive pound signs are replaced with a single pound
286 sign. The filename is inserted into the command line list of
287 files so that it can be seen by subsequent :n and :p commands.
288 If the filename consists of several files, they are all inserted
289 into the list of files and the first one is examined. If the
290 filename contains one or more spaces, the entire filename should
291 be enclosed in double quotes (also see the -" option).
294 Same as :e. Warning: some systems use ^V as a special literal-
295 ization character. On such systems, you may not be able to use
298 :n Examine the next file (from the list of files given in the com-
299 mand line). If a number N is specified, the N-th next file is
302 :p Examine the previous file in the command line list. If a number
303 N is specified, the N-th previous file is examined.
305 :x Examine the first file in the command line list. If a number N
306 is specified, the N-th file in the list is examined.
308 :d Remove the current file from the list of files.
310 t Go to the next tag, if there were more than one matches for the
311 current tag. See the -t option for more details about tags.
313 T Go to the previous tag, if there were more than one matches for
317 Prints some information about the file being viewed, including
318 its name and the line number and byte offset of the bottom line
319 being displayed. If possible, it also prints the length of the
320 file, the number of lines in the file and the percent of the
321 file above the last displayed line.
323 - Followed by one of the command line option letters (see OPTIONS
324 below), this will change the setting of that option and print a
325 message describing the new setting. If a ^P (CONTROL-P) is
326 entered immediately after the dash, the setting of the option is
327 changed but no message is printed. If the option letter has a
328 numeric value (such as -b or -h), or a string value (such as -P
329 or -t), a new value may be entered after the option letter. If
330 no new value is entered, a message describing the current set-
331 ting is printed and nothing is changed.
333 -- Like the - command, but takes a long option name (see OPTIONS
334 below) rather than a single option letter. You must press
335 RETURN after typing the option name. A ^P immediately after the
336 second dash suppresses printing of a message describing the new
337 setting, as in the - command.
339 -+ Followed by one of the command line option letters this will
340 reset the option to its default setting and print a message
341 describing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
342 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
343 string-valued options.
345 --+ Like the -+ command, but takes a long option name rather than a
346 single option letter.
348 -! Followed by one of the command line option letters, this will
349 reset the option to the "opposite" of its default setting and
350 print a message describing the new setting. This does not work
351 for numeric or string-valued options.
353 --! Like the -! command, but takes a long option name rather than a
354 single option letter.
356 _ (Underscore.) Followed by one of the command line option let-
357 ters, this will print a message describing the current setting
358 of that option. The setting of the option is not changed.
360 __ (Double underscore.) Like the _ (underscore) command, but takes
361 a long option name rather than a single option letter. You must
362 press RETURN after typing the option name.
364 +cmd Causes the specified cmd to be executed each time a new file is
365 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
366 file starting at the end rather than the beginning.
368 V Prints the version number of
\e[4mless
\e[24m being run.
370 q or Q or :q or :Q or ZZ
371 Exits
\e[4mless.
\e[0m
373 The following four commands may or may not be valid, depending on your
374 particular installation.
377 v Invokes an editor to edit the current file being viewed. The
378 editor is taken from the environment variable VISUAL if defined,
379 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
380 ther VISUAL nor EDITOR is defined. See also the discussion of
381 LESSEDIT under the section on PROMPTS below.
384 Invokes a shell to run the shell-command given. A percent sign
385 (%) in the command is replaced by the name of the current file.
386 A pound sign (#) is replaced by the name of the previously exam-
387 ined file. "!!" repeats the last shell command. "!" with no
388 shell command simply invokes a shell. On Unix systems, the
389 shell is taken from the environment variable SHELL, or defaults
390 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
394 <m> represents any mark letter. Pipes a section of the input
395 file to the given shell command. The section of the file to be
396 piped is between the first line on the current screen and the
397 position marked by the letter. <m> may also be ^ or $ to indi-
398 cate beginning or end of file respectively. If <m> is . or new-
399 line, the current screen is piped.
402 Save the input to a file. This only works if the input is a
403 pipe, not an ordinary file.
407 Command line options are described below. Most options may be changed
408 while
\e[4mless
\e[24m is running, via the "-" command.
410 Most options may be given in one of two forms: either a dash followed
411 by a single letter, or two dashes followed by a long option name. A
412 long option name may be abbreviated as long as the abbreviation is
413 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
414 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
415 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
416 from --quit-at-eof. Such option names need only have their first let-
417 ter capitalized; the remainder of the name may be in either case. For
418 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
420 Options are also taken from the environment variable "LESS". For exam-
421 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
422 might tell
\e[4mcsh:
\e[0m
424 setenv LESS "-options"
426 or if you use
\e[4msh:
\e[0m
428 LESS="-options"; export LESS
430 On MS-DOS, you don't need the quotes, but you should replace any per-
431 cent signs in the options string by double percent signs.
433 The environment variable is parsed before the command line, so command
434 line options override the LESS environment variable. If an option
435 appears in the LESS variable, it can be reset to its default value on
436 the command line by beginning the command line option with "-+".
438 For options like -P or -D which take a following string, a dollar sign
439 ($) must be used to signal the end of the string. For example, to set
440 two -D options on MS-DOS, you must have a dollar sign between them,
447 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
448 (the same as the h command). (Depending on how your shell
449 interprets the question mark, it may be necessary to quote the
450 question mark, thus: "-\?".)
452 -a or --search-skip-screen
453 Causes searches to start after the last line displayed on the
454 screen, thus skipping all lines displayed on the screen. By
455 default, searches start at the second line on the screen (or
456 after the last found line; see the -j option).
458 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
459 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
460 file, in units of kilobytes (1024 bytes). By default 64K of
461 buffer space is used for each file (unless the file is a pipe;
462 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
463 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
464 -1, buffer space is unlimited; that is, the entire file can be
468 By default, when data is read from a pipe, buffers are allocated
469 automatically as needed. If a large amount of data is read from
470 the pipe, this can cause a large amount of memory to be allo-
471 cated. The -B option disables this automatic allocation of
472 buffers for pipes, so that only 64K (or the amount of space
473 specified by the -b option) is used for the pipe. Warning: use
474 of -B can result in erroneous display, since only the most
475 recently viewed part of the piped data is kept in memory; any
476 earlier data is lost.
479 Causes full screen repaints to be painted from the top line
480 down. By default, full screen repaints are done by scrolling
481 from the bottom of the screen.
484 Same as -c, for compatibility with older versions of
\e[4mless.
\e[0m
487 The -d option suppresses the error message normally displayed if
488 the terminal is dumb; that is, lacks some important capability,
489 such as the ability to clear the screen or scroll backward. The
490 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
493 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
494 [MS-DOS only] Sets the color of the text displayed.
\e[1mx
\e[22mis a sin-
495 gle character which selects the type of text whose color is
496 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
497 \e[4mcolor
\e[24m is a pair of numbers separated by a period. The first
498 number selects the foreground color and the second selects the
499 background color of the text. A single number
\e[4mN
\e[24m is the same as
500 \e[4mN.M
\e[24m, where
\e[4mM
\e[24m is the normal background color.
504 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
505 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
509 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
513 Forces non-regular files to be opened. (A non-regular file is a
514 directory or a device special file.) Also suppresses the warn-
515 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
516 refuse to open non-regular files. Note that some operating sys-
517 tems will not allow directories to be read, even if -f is set.
519 -F or --quit-if-one-screen
520 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
521 played on the first screen.
523 -g or --hilite-search
524 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
525 search command. The -g option changes this behavior to high-
526 light only the particular string which was found by the last
527 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
530 -G or --HILITE-SEARCH
531 The -G option suppresses all highlighting of strings found by
534 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
535 Specifies a maximum number of lines to scroll backward. If it
536 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
537 repainted in a forward direction instead. (If the terminal does
538 not have the ability to scroll backward, -h0 is implied.)
541 Causes searches to ignore case; that is, uppercase and lowercase
542 are considered identical. This option is ignored if any upper-
543 case letters appear in the search pattern; in other words, if a
544 pattern contains uppercase letters, then that search does not
548 Like -i, but searches ignore case even if the pattern contains
551 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
552 Specifies a line on the screen where the "target" line is to be
553 positioned. The target line is the line specified by any com-
554 mand to search for a pattern, jump to a line number, jump to a
555 file percentage or jump to a tag. The screen line may be speci-
556 fied by a number: the top line on the screen is 1, the next is
557 2, and so on. The number may be negative to specify a line rel-
558 ative to the bottom of the screen: the bottom line on the screen
559 is -1, the second to the bottom is -2, and so on. Alternately,
560 the screen line may be specified as a fraction of the height of
561 the screen, starting with a decimal point: .5 is in the middle
562 of the screen, .3 is three tenths down from the first line, and
563 so on. If the line is specified as a fraction, the actual line
564 number is recalculated if the terminal window is resized, so
565 that the target line remains at the specified fraction of the
566 screen height. If any form of the -j option is used, forward
567 searches begin at the line immediately after the target line,
568 and backward searches begin at the target line. For example, if
569 "-j4" is used, the target line is the fourth line on the screen,
570 so forward searches begin at the fifth line on the screen.
572 -J or --status-column
573 Displays a status column at the left edge of the screen. The
574 status column shows the lines that matched the current search.
575 The status column is also used if the -w or -W option is in
578 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
579 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[0m
580 (1) file. Multiple -k options may be specified. If the LESSKEY
581 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
582 file is found in a standard place (see KEY BINDINGS), it is also
583 used as a
\e[4mlesskey
\e[24m file.
586 Causes
\e[4mless
\e[24m to exit immediately when an interrupt character
587 (usually ^C) is typed. Normally, an interrupt character causes
588 \e[4mless
\e[24m to stop whatever it is doing and return to its command
589 prompt. Note that use of this option makes it impossible to
590 return to the command prompt from the "F" command.
593 Ignore the LESSOPEN environment variable (see the INPUT PRE-
594 PROCESSOR section below). This option can be set from within
595 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
596 to the file which is currently open.
599 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
600 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
603 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore.
\e[0m
606 Suppresses line numbers. The default (to use line numbers) may
607 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
608 very large input file. Suppressing line numbers with the -n
609 option will avoid this problem. Using line numbers means: the
610 line number will be displayed in the verbose prompt and in the =
611 command, and the v command will pass the current line number to
612 the editor (see also the discussion of LESSEDIT in PROMPTS
616 Causes a line number to be displayed at the beginning of each
619 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
620 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
621 viewed. This applies only when the input file is a pipe, not an
622 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
623 confirmation before overwriting it.
625 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
626 The -O option is like -o, but it will overwrite an existing file
627 without asking for confirmation.
629 If no log file has been specified, the -o and -O options can be
630 used from within
\e[4mless
\e[24m to specify a log file. Without a file
631 name, they will simply report the name of the log file. The "s"
632 command is equivalent to specifying -o from within
\e[4mless.
\e[0m
634 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
635 The -p option on the command line is equivalent to specifying
636 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
637 rence of
\e[4mpattern
\e[24m in the file.
639 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
640 Provides a way to tailor the three prompt styles to your own
641 preference. This option would normally be put in the LESS envi-
642 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
643 mand. Such an option must either be the last option in the LESS
644 variable, or be terminated by a dollar sign. -Ps followed by a
645 string changes the default (short) prompt to that string. -Pm
646 changes the medium (-m) prompt. -PM changes the long (-M)
647 prompt. -Ph changes the prompt for the help screen. -P=
648 changes the message printed by the = command. -Pw changes the
649 message printed while waiting for data (in the F command). All
650 prompt strings consist of a sequence of letters and special
651 escape sequences. See the section on PROMPTS for more details.
653 -q or --quiet or --silent
654 Causes moderately "quiet" operation: the terminal bell is not
655 rung if an attempt is made to scroll past the end of the file or
656 before the beginning of the file. If the terminal has a "visual
657 bell", it is used instead. The bell will be rung on certain
658 other errors, such as typing an invalid character. The default
659 is to ring the terminal bell in all such cases.
661 -Q or --QUIET or --SILENT
662 Causes totally "quiet" operation: the terminal bell is never
665 -r or --raw-control-chars
666 Causes "raw" control characters to be displayed. The default is
667 to display control characters using the caret notation; for
668 example, a control-A (octal 001) is displayed as "^A". Warning:
669 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
670 appearance of the screen (since this depends on how the screen
671 responds to each type of control character). Thus, various dis-
672 play problems may result, such as long lines being split in the
675 -R or --RAW-CONTROL-CHARS
676 Like -r, but only ANSI "color" escape sequences are output in
677 "raw" form. Unlike -r, the screen appearance is maintained cor-
678 rectly in most cases. ANSI "color" escape sequences are
679 sequences of the form:
683 where the "..." is zero or more color specification characters
684 For the purpose of keeping track of screen appearance, ANSI
685 color escape sequences are assumed to not move the cursor. You
686 can make
\e[4mless
\e[24m think that characters other than "m" can end ANSI
687 color escape sequences by setting the environment variable
688 LESSANSIENDCHARS to the list of characters which can end a color
689 escape sequence. And you can make
\e[4mless
\e[24m think that characters
690 other than the standard ones may appear between the ESC and the
691 m by setting the environment variable LESSANSIMIDCHARS to the
692 list of characters which can appear.
694 -s or --squeeze-blank-lines
695 Causes consecutive blank lines to be squeezed into a single
696 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
698 -S or --chop-long-lines
699 Causes lines longer than the screen width to be chopped rather
700 than folded. That is, the portion of a long line that does not
701 fit in the screen width is not shown. The default is to fold
702 long lines; that is, display the remainder on the next line.
704 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
705 The -t option, followed immediately by a TAG, will edit the file
706 containing that tag. For this to work, tag information must be
707 available; for example, there may be a file in the current
708 directory called "tags", which was previously built by
\e[4mctags
\e[24m (1)
709 or an equivalent command. If the environment variable LESSGLOB-
710 ALTAGS is set, it is taken to be the name of a command compati-
711 ble with
\e[4mglobal
\e[24m (1), and that command is executed to find the
712 tag. (See http://www.gnu.org/software/global/global.html). The
713 -t option may also be specified from within
\e[4mless
\e[24m (using the -
714 command) as a way of examining a new file. The command ":t" is
715 equivalent to specifying -t from within
\e[4mless.
\e[0m
717 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
718 Specifies a tags file to be used instead of "tags".
720 -u or --underline-special
721 Causes backspaces and carriage returns to be treated as print-
722 able characters; that is, they are sent to the terminal when
723 they appear in the input.
725 -U or --UNDERLINE-SPECIAL
726 Causes backspaces, tabs and carriage returns to be treated as
727 control characters; that is, they are handled as specified by
730 By default, if neither -u nor -U is given, backspaces which
731 appear adjacent to an underscore character are treated spe-
732 cially: the underlined text is displayed using the terminal's
733 hardware underlining capability. Also, backspaces which appear
734 between two identical characters are treated specially: the
735 overstruck text is printed using the terminal's hardware bold-
736 face capability. Other backspaces are deleted, along with the
737 preceding character. Carriage returns immediately followed by a
738 newline are deleted. other carriage returns are handled as
739 specified by the -r option. Text which is overstruck or under-
740 lined can be searched for if neither -u nor -U is in effect.
743 Displays the version number of
\e[4mless.
\e[0m
745 -w or --hilite-unread
746 Temporarily highlights the first "new" line after a forward
747 movement of a full page. The first "new" line is the line imme-
748 diately following the line previously at the bottom of the
749 screen. Also highlights the target line after a g or p command.
750 The highlight is removed at the next command which causes move-
751 ment. The entire line is highlighted, unless the -J option is
752 in effect, in which case only the status column is highlighted.
754 -W or --HILITE-UNREAD
755 Like -w, but temporarily highlights the first new line after any
756 forward movement command larger than one line.
758 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
759 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
760 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
761 specified, tab stops are set at those positions, and then con-
762 tinue with the same spacing as the last two. For example,
763 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The
764 default for
\e[4mn
\e[24m is 8.
767 Disables sending the termcap initialization and deinitialization
768 strings to the terminal. This is sometimes desirable if the
769 deinitialization string does something unnecessary, like clear-
772 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
773 Specifies a maximum number of lines to scroll forward. If it is
774 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is
775 repainted instead. The -c or -C option may be used to repaint
776 from the top of the screen if desired. By default, any forward
777 movement causes scrolling.
779 -[z]
\e[4mn
\e[24m or --window=
\e[4mn
\e[0m
780 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The
781 default is one screenful. The z and w commands can also be used
782 to change the window size. The "z" may be omitted for compati-
783 bility with some versions of
\e[4mmore.
\e[24m If the number
\e[4mn
\e[24m is negative,
784 it indicates
\e[4mn
\e[24m lines less than the current screen size. For
785 example, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling win-
786 dow to 20 lines. If the screen is resized to 40 lines, the
787 scrolling window automatically changes to 36 lines.
789 -
\e[4m"cc
\e[24m or --quotes=
\e[4mcc
\e[0m
790 Changes the filename quoting character. This may be necessary
791 if you are trying to name a file which contains both spaces and
792 quote characters. Followed by a single character, this changes
793 the quote character to that character. Filenames containing a
794 space should then be surrounded by that character rather than by
795 double quotes. Followed by two characters, changes the open
796 quote to the first character, and the close quote to the second
797 character. Filenames containing a space should then be preceded
798 by the open quote character and followed by the close quote
799 character. Note that even after the quote characters are
800 changed, this option remains -" (a dash followed by a double
804 Normally lines after end of file are displayed as a single tilde
805 (~). This option causes lines after end of file to be displayed
809 Specifies the default number of positions to scroll horizontally
810 in the RIGHTARROW and LEFTARROW commands. If the number speci-
811 fied is zero, it sets the default number of positions to one
812 half of the screen width. Alternately, the number may be speci-
813 fied as a fraction of the width of the screen, starting with a
814 decimal point: .5 is half of the screen width, .3 is three
815 tenths of the screen width, and so on. If the number is speci-
816 fied as a fraction, the actual number of scroll positions is
817 recalculated if the terminal window is resized, so that the
818 actual scroll remains at the specified fraction of the screen
822 Disables sending the keypad initialization and deinitialization
823 strings to the terminal. This is sometimes useful if the keypad
824 strings make the numeric keypad behave in an undesirable manner.
827 Normally, if the input file is renamed while an F command is
828 executing,
\e[4mless
\e[24m will continue to display the contents of the
829 original file despite its name change. If --follow-name is
830 specified, during an F command
\e[4mless
\e[24m will periodically attempt to
831 reopen the file by name. If the reopen succeeds and the file is
832 a different file from the original (which means that a new file
833 has been created with the same name as the original (now
834 renamed) file),
\e[4mless
\e[24m will display the contents of that new file.
836 -- A command line argument of "--" marks the end of option argu-
837 ments. Any arguments following this are interpreted as file-
838 names. This can be useful when viewing a file whose name begins
841 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
842 option is taken to be an initial command to
\e[4mless.
\e[24m For example,
843 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
844 beginning, and +/xyz tells it to start at the first occurrence
845 of "xyz" in the file. As a special case, +<number> acts like
846 +<number>g; that is, it starts the display at the specified line
847 number (however, see the caveat under the "g" command above).
848 If the option starts with ++, the initial command applies to
849 every file being viewed, not just the first one. The + command
850 described previously may also be used to set (or change) an ini-
851 tial command for every file.
854 \e[1mLINE EDITING
\e[0m
855 When entering command line at the bottom of the screen (for example, a
856 filename for the :e command, or the pattern for a search command), cer-
857 tain keys can be used to manipulate the command line. Most commands
858 have an alternate form in [ brackets ] which can be used if a key does
859 not exist on a particular keyboard. (Note that the forms beginning
860 with ESC do not work in some MS-DOS and Windows systems because ESC is
861 the line erase character.) Any of these special keys may be entered
862 literally by preceding it with the "literal" character, either ^V or
863 ^A. A backslash itself may also be entered literally by entering two
867 Move the cursor one space to the left.
870 Move the cursor one space to the right.
872 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
873 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
874 sor one word to the left.
876 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
877 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
878 sor one word to the right.
881 Move the cursor to the beginning of the line.
884 Move the cursor to the end of the line.
887 Delete the character to the left of the cursor, or cancel the
888 command if the command line is empty.
891 Delete the character under the cursor.
893 ^BACKSPACE [ ESC-BACKSPACE ]
894 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
895 word to the left of the cursor.
897 ^DELETE [ ESC-X or ESC-DELETE ]
898 (That is, CONTROL and DELETE simultaneously.) Delete the word
902 Retrieve the previous command line.
905 Retrieve the next command line.
907 TAB Complete the partial filename to the left of the cursor. If it
908 matches more than one filename, the first match is entered into
909 the command line. Repeated TABs will cycle thru the other
910 matching filenames. If the completed filename is a directory, a
911 "/" is appended to the filename. (On MS-DOS systems, a "\" is
912 appended.) The environment variable LESSSEPARATOR can be used
913 to specify a different character to append to a directory name.
916 Like, TAB, but cycles in the reverse direction thru the matching
919 ^L Complete the partial filename to the left of the cursor. If it
920 matches more than one filename, all matches are entered into the
921 command line (if they fit).
923 ^U (Unix and OS/2) or ESC (MS-DOS)
924 Delete the entire command line, or cancel the command if the
925 command line is empty. If you have changed your line-kill char-
926 acter in Unix to something other than ^U, that character is used
930 \e[1mKEY BINDINGS
\e[0m
931 You may define your own
\e[4mless
\e[24m commands by using the program
\e[4mlesskey
\e[24m (1)
932 to create a lesskey file. This file specifies a set of command keys
933 and an action associated with each key. You may also use
\e[4mlesskey
\e[24m to
934 change the line-editing keys (see LINE EDITING), and to set environment
935 variables. If the environment variable LESSKEY is set,
\e[4mless
\e[24m uses that
936 as the name of the lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard
937 place for the lesskey file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey
938 file called "$HOME/.less". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks
939 for a lesskey file called "$HOME/_less", and if it is not found there,
940 then looks for a lesskey file called "_less" in any directory specified
941 in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for a
942 lesskey file called "$HOME/less.ini", and if it is not found, then
943 looks for a lesskey file called "less.ini" in any directory specified
944 in the INIT environment variable, and if it not found there, then looks
945 for a lesskey file called "less.ini" in any directory specified in the
946 PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for more
949 A system-wide lesskey file may also be set up to provide key bindings.
950 If a key is defined in both a local lesskey file and in the system-wide
951 file, key bindings in the local file take precedence over those in the
952 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
953 \e[4mless
\e[24m uses that as the name of the system-wide lesskey file. Otherwise,
954 \e[4mless
\e[24m looks in a standard place for the system-wide lesskey file: On
955 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
956 (However, if
\e[4mless
\e[24m was built with a different sysconf directory than
957 /usr/local/etc, that directory is where the sysless file is found.) On
958 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys-
959 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
962 \e[1mINPUT PREPROCESSOR
\e[0m
963 You may define an "input preprocessor" for
\e[4mless.
\e[24m Before
\e[4mless
\e[24m opens a
964 file, it first gives your input preprocessor a chance to modify the way
965 the contents of the file are displayed. An input preprocessor is sim-
966 ply an executable program (or shell script), which writes the contents
967 of the file to a different file, called the replacement file. The con-
968 tents of the replacement file are then displayed in place of the con-
969 tents of the original file. However, it will appear to the user as if
970 the original file is opened; that is,
\e[4mless
\e[24m will display the original
971 filename as the name of the current file.
973 An input preprocessor receives one command line argument, the original
974 filename, as entered by the user. It should create the replacement
975 file, and when finished, print the name of the replacement file to its
976 standard output. If the input preprocessor does not output a replace-
977 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
978 processor is not called when viewing standard input. To set up an
979 input preprocessor, set the LESSOPEN environment variable to a command
980 line which will invoke your input preprocessor. This command line
981 should include one occurrence of the string "%s", which will be
982 replaced by the filename when the input preprocessor command is
985 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
986 gram, called the input postprocessor, which may perform any desired
987 clean-up action (such as deleting the replacement file created by
988 LESSOPEN). This program receives two command line arguments, the orig-
989 inal filename as entered by the user, and the name of the replacement
990 file. To set up an input postprocessor, set the LESSCLOSE environment
991 variable to a command line which will invoke your input postprocessor.
992 It may include two occurrences of the string "%s"; the first is
993 replaced with the original name of the file and the second with the
994 name of the replacement file, which was output by LESSOPEN.
996 For example, on many Unix systems, these two scripts will allow you to
997 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1003 if [ -s /tmp/less.$$ ]; then
1015 To use these scripts, put them both where they can be executed and set
1016 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1017 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1018 types of compressed files, and so on.
1020 It is also possible to set up an input preprocessor to pipe the file
1021 data directly to
\e[4mless,
\e[24m rather than putting the data into a replacement
1022 file. This avoids the need to decompress the entire file before start-
1023 ing to view it. An input preprocessor that works this way is called an
1024 input pipe. An input pipe, instead of writing the name of a replace-
1025 ment file on its standard output, writes the entire contents of the
1026 replacement file on its standard output. If the input pipe does not
1027 write any characters on its standard output, then there is no replace-
1028 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1029 pipe, make the first character in the LESSOPEN environment variable a
1030 vertical bar (|) to signify that the input preprocessor is an input
1033 For example, on many Unix systems, this script will work like the pre-
1034 vious example scripts:
1039 *.Z) uncompress -c $1 2>/dev/null
1043 To use this script, put it where it can be executed and set
1044 LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a LESSCLOSE
1045 postprocessor can be used, but it is usually not necessary since there
1046 is no replacement file to clean up. In this case, the replacement file
1047 name passed to the LESSCLOSE postprocessor is "-".
1049 For compatibility with previous versions of
\e[4mless,
\e[24m the input preproces-
1050 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1051 the first character of LESSOPEN is a dash (-), the input preprocessor
1052 is used on standard input as well as other files. In this case, the
1053 dash is not considered to be part of the preprocessor command. If
1054 standard input is being viewed, the input preprocessor is passed a file
1055 name consisting of a single dash. Similarly, if the first two charac-
1056 ters of LESSOPEN are vertical bar and dash (|-), the input pipe is used
1057 on standard input as well as other files. Again, in this case the dash
1058 is not considered to be part of the input pipe command.
1061 \e[1mNATIONAL CHARACTER SETS
\e[0m
1062 There are three types of characters in the input file:
1065 can be displayed directly to the screen.
1068 should not be displayed directly, but are expected to be found
1069 in ordinary text files (such as backspace and tab).
1072 should not be displayed directly and are not expected to be
1073 found in text files.
1075 A "character set" is simply a description of which characters are to be
1076 considered normal, control, and binary. The LESSCHARSET environment
1077 variable may be used to select a character set. Possible values for
1080 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1081 with values between 32 and 126 are normal, and all others are
1085 Selects an ISO 8859 character set. This is the same as ASCII,
1086 except characters between 160 and 255 are treated as normal
1089 latin1 Same as iso8859.
1091 latin9 Same as iso8859.
1093 dos Selects a character set appropriate for MS-DOS.
1095 ebcdic Selects an EBCDIC character set.
1098 Selects an EBCDIC character set used by OS/390 Unix Services.
1099 This is the EBCDIC analogue of latin1. You get similar results
1100 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1103 koi8-r Selects a Russian character set.
1105 next Selects a character set appropriate for NeXT computers.
1107 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1108 UTF-8 is special in that it supports multi-byte characters in
1109 the input file. It is the only character set that supports
1110 multi-byte characters.
1113 Selects a character set appropriate for Microsoft Windows (cp
1116 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1117 other than the ones definable by LESSCHARSET. In this case, the envi-
1118 ronment variable LESSCHARDEF can be used to define a character set. It
1119 should be set to a string where each character in the string represents
1120 one character in the character set. The character "." is used for a
1121 normal character, "c" for control, and "b" for binary. A decimal num-
1122 ber may be used for repetition. For example, "bccc4b." would mean
1123 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1124 binary, and 8 is normal. All characters after the last are taken to be
1125 the same as the last, so characters 9 through 255 would be normal.
1126 (This is an example, and does not necessarily represent any real char-
1129 This table shows the value of LESSCHARDEF which is equivalent to each
1130 of the possible values for LESSCHARSET:
1132 ascii 8bcccbcc18b95.b
1133 dos 8bcccbcc12bc5b95.b.
1134 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1135 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1136 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1138 iso8859 8bcccbcc18b95.33b.
1139 koi8-r 8bcccbcc18b95.b128.
1140 latin1 8bcccbcc18b95.33b.
1141 next 8bcccbcc18b95.bb125.bb
1143 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1144 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_TYPE or
1145 LANG environment variables, then the default character set is utf-8.
1147 If that string is not found, but your system supports the
\e[4msetlocale
\e[0m
1148 interface,
\e[4mless
\e[24m will use setlocale to determine the character set.
1149 setlocale is controlled by setting the LANG or LC_CTYPE environment
1152 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1153 character set is latin1.
1155 Control and binary characters are displayed in standout (reverse
1156 video). Each such character is displayed in caret notation if possible
1157 (e.g. ^A for control-A). Caret notation is used only if inverting the
1158 0100 bit results in a normal printable character. Otherwise, the char-
1159 acter is displayed as a hex number in angle brackets. This format can
1160 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1161 may begin with a "*" and one character to select the display attribute:
1162 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1163 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1164 attribute is assumed. The remainder of LESSBINFMT is a string which
1165 may include one printf-style escape sequence (a % followed by x, X, o,
1166 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1167 are displayed in underlined hexadecimal surrounded by brackets. The
1168 default if no LESSBINFMT is specified is "*s<%X>". The default if no
1169 LESSBINFMT is specified is "*s<%02X>". Warning: the result of expand-
1170 ing the character via LESSBINFMT must be less than 31 characters.
1172 When the character set is utf-8, the LESSUTFBINFMT environment variable
1173 acts similarly to LESSBINFMT but it applies to Unicode code points that
1174 were successfully decoded but are unsuitable for display (e.g., unas-
1175 signed code points). Its default value is "<U+%04lX>". Note that
1176 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1177 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1178 LESSBINFMT so its setting, if any, will have priority. Problematic
1179 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1180 complete but non-shortest form sequence, illegal octets, and stray
1181 trailing octets) are displayed individually using LESSBINFMT so as to
1182 facilitate diagnostic of how the UTF-8 file is ill-formed.
1186 The -P option allows you to tailor the prompt to your preference. The
1187 string given to the -P option replaces the specified prompt string.
1188 Certain characters in the string are interpreted specially. The prompt
1189 mechanism is rather complicated to provide flexibility, but the ordi-
1190 nary user need not understand the details of constructing personalized
1193 A percent sign followed by a single character is expanded according to
1194 what the following character is:
1196 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1197 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1198 ifies the line whose byte offset is to be used. If the charac-
1199 ter is a "t", the byte offset of the top line in the display is
1200 used, an "m" means use the middle line, a "b" means use the bot-
1201 tom line, a "B" means use the line just after the bottom line,
1202 and a "j" means use the "target" line, as specified by the -j
1205 %B Replaced by the size of the current input file.
1207 %c Replaced by the column number of the text appearing in the first
1208 column of the screen.
1210 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1211 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1213 %D Replaced by the number of pages in the input file, or equiva-
1214 lently, the page number of the last line in the input file.
1216 %E Replaced by the name of the editor (from the VISUAL environment
1217 variable, or the EDITOR environment variable if VISUAL is not
1218 defined). See the discussion of the LESSEDIT feature below.
1220 %f Replaced by the name of the current input file.
1222 %i Replaced by the index of the current file in the list of input
1225 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1226 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1228 %L Replaced by the line number of the last line in the input file.
1230 %m Replaced by the total number of input files.
1232 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1233 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1236 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1237 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1242 %t Causes any trailing spaces to be removed. Usually used at the
1243 end of the string, but may appear anywhere.
1245 %x Replaced by the name of the next input file in the list.
1247 If any item is unknown (for example, the file size if input is a pipe),
1248 a question mark is printed instead.
1250 The format of the prompt string can be changed depending on certain
1251 conditions. A question mark followed by a single character acts like
1252 an "IF": depending on the following character, a condition is evalu-
1253 ated. If the condition is true, any characters following the question
1254 mark and condition character, up to a period, are included in the
1255 prompt. If the condition is false, such characters are not included.
1256 A colon appearing between the question mark and the period can be used
1257 to establish an "ELSE": any characters between the colon and the period
1258 are included in the string if and only if the IF condition is false.
1259 Condition characters (which follow a question mark) may be:
1261 ?a True if any characters have been included in the prompt so far.
1263 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1265 ?B True if the size of current input file is known.
1267 ?c True if the text is horizontally shifted (%c is not zero).
1269 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1271 ?e True if at end-of-file.
1273 ?f True if there is an input filename (that is, if input is not a
1276 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1278 ?L True if the line number of the last line in the file is known.
1280 ?m True if there is more than one input file.
1282 ?n True if this is the first prompt in a new input file.
1284 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1285 offsets, of the specified line is known.
1287 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1288 numbers, of the specified line is known.
1292 ?x True if there is a next input file (that is, if the current
1293 input file is not the last one).
1295 Any characters other than the special ones (question mark, colon,
1296 period, percent, and backslash) become literally part of the prompt.
1297 Any of the special characters may be included in the prompt literally
1298 by preceding it with a backslash.
1302 ?f%f:Standard input.
1304 This prompt prints the filename, if known; otherwise the string "Stan-
1307 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1309 This prompt would print the filename, if known. The filename is fol-
1310 lowed by the line number, if known, otherwise the percent if known,
1311 otherwise the byte offset if known. Otherwise, a dash is printed.
1312 Notice how each question mark has a matching period, and how the %
1313 after the %pt is included literally by escaping it with a backslash.
1315 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t
1317 This prints the filename if this is the first prompt in a file, fol-
1318 lowed by the "file N of N" message if there is more than one input
1319 file. Then, if we are at end-of-file, the string "(END)" is printed
1320 followed by the name of the next file, if there is one. Finally, any
1321 trailing spaces are truncated. This is the default prompt. For refer-
1322 ence, here are the defaults for the other two prompts (-m and -M
1323 respectively). Each is broken into two lines here for readability
1326 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.:
1327 ?pB%pB\%:byte %bB?s/%s...%t
1329 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. :
1330 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1332 And here is the default message produced by the = command:
1334 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. .
1335 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1337 The prompt expansion features are also used for another purpose: if an
1338 environment variable LESSEDIT is defined, it is used as the command to
1339 be executed when the v command is invoked. The LESSEDIT string is
1340 expanded in the same way as the prompt strings. The default value for
1345 Note that this expands to the editor name, followed by a + and the line
1346 number, followed by the file name. If your editor does not accept the
1347 "+linenumber" syntax, or has other differences in invocation syntax,
1348 the LESSEDIT variable can be changed to modify this default.
1352 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1353 "secure" mode. This means these features are disabled:
1359 :e the examine command.
1361 v the editing command
1365 -k use of lesskey files
1367 -t use of tags files
1369 metacharacters in filenames, such as *
1371 filename completion (TAB, ^L)
1373 Less can also be compiled to be permanently in "secure" mode.
1376 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1377 If the environment variable LESS_IS_MORE is set to 1, or if the program
1378 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1379 formance with the POSIX "more" command specification. In this mode,
1380 less behaves differently in these ways:
1382 The -e option works differently. If the -e option is not set,
\e[4mless
\e[0m
1383 behaves as if the -E option were set. If the -e option is set,
\e[4mless
\e[0m
1384 behaves as if the -e and -F options were set.
1386 The -m option works differently. If the -m option is not set, the
1387 medium prompt is used, and it is prefixed with the string "--More--".
1388 If the -m option is set, the short prompt is used.
1390 The -n option acts like the -z option. The normal behavior of the -n
1391 option is unavailable in this mode.
1393 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1394 than a search pattern.
1396 The LESS environment variable is ignored, and the MORE environment
1397 variable is used in its place.
1400 \e[1mENVIRONMENT VARIABLES
\e[0m
1401 Environment variables may be specified either in the system environment
1402 as usual, or in a
\e[4mlesskey
\e[24m (1) file. If environment variables are
1403 defined in more than one place, variables defined in a local lesskey
1404 file take precedence over variables defined in the system environment,
1405 which take precedence over variables defined in the system-wide lesskey
1409 Sets the number of columns on the screen. Takes precedence over
1410 the number of columns specified by the TERM variable. (But if
1411 you have a windowing system which supports TIOCGWINSZ or
1412 WIOCGETD, the window system's idea of the screen size takes
1413 precedence over the LINES and COLUMNS environment variables.)
1415 EDITOR The name of the editor (used for the v command).
1417 HOME Name of the user's home directory (used to find a lesskey file
1418 on Unix and OS/2 systems).
1421 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1422 ables is the name of the user's home directory if the HOME vari-
1423 able is not set (only in the Windows version).
1425 INIT Name of the user's init directory (used to find a lesskey file
1428 LANG Language for determining the character set.
1431 Language for determining the character set.
1433 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1436 Characters which may end an ANSI color escape sequence (default
1440 Characters which may appear between the ESC character and the
1441 end character in an ANSI color escape sequence (default
1442 "0123456789;[?!"'#%()*+ ".
1445 Format for displaying non-printable, non-control characters.
1448 Defines a character set.
1451 Selects a predefined character set.
1454 Command line to invoke the (optional) input-postprocessor.
1457 Name of the lessecho program (default "lessecho"). The lessecho
1458 program is needed to expand metacharacters, such as * and ?, in
1459 filenames on Unix systems.
1462 Editor prototype string (used for the v command). See discus-
1466 Name of the command used by the -t option to find global tags.
1467 Normally should be set to "global" if your system has the
\e[4mglobal
\e[0m
1468 (1) command. If not set, global tags are not used.
1471 Name of the history file used to remember search commands and
1472 shell commands between invocations of
\e[4mless.
\e[24m If set to "-" or
1473 "/dev/null", a history file is not used. The default is
1474 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1475 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1479 The maximum number of commands to save in the history file. The
1483 Name of the default lesskey(1) file.
1486 Name of the default system-wide lesskey(1) file.
1489 List of characters which are considered "metacharacters" by the
1493 Prefix which less will add before each metacharacter in a com-
1494 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1495 commands containing metacharacters will not be passed to the
1499 Command line to invoke the (optional) input-preprocessor.
1502 Runs less in "secure" mode. See discussion under SECURITY.
1505 String to be appended to a directory name in filename comple-
1509 Format for displaying non-printable Unicode code points.
1512 Emulate the
\e[4mmore
\e[24m (1) command.
1514 LINES Sets the number of lines on the screen. Takes precedence over
1515 the number of lines specified by the TERM variable. (But if you
1516 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1517 the window system's idea of the screen size takes precedence
1518 over the LINES and COLUMNS environment variables.)
1520 PATH User's search path (used to find a lesskey file on MS-DOS and
1523 SHELL The shell used to execute the ! command, as well as to expand
1526 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1528 VISUAL The name of the editor (used for the v command).
1536 Copyright (C) 1984-2009 Mark Nudelman
1538 less is part of the GNU project and is free software. You can redis-
1539 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1540 eral Public License as published by the Free Software Foundation; or
1541 (2) the Less License. See the file README in the less distribution for
1542 more details regarding redistribution. You should have received a copy
1543 of the GNU General Public License along with the source for less; see
1544 the file COPYING. If not, write to the Free Software Foundation, 59
1545 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1546 have received a copy of the Less License; see the file LICENSE.
1548 less is distributed in the hope that it will be useful, but WITHOUT ANY
1549 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1550 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1555 Mark Nudelman <markn@greenwoodsoftware.com>
1556 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1557 of known bugs in less.
1558 Send bug reports or comments to the above address or to
1560 For more information, see the less homepage at
1561 http://www.greenwoodsoftware.com/less.
1565 Version 436: 07 Jul 2009 LESS(1)