6 less - opposite of more
12 \e[1mless --version
\e[0m
13 \e[1mless [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
\e[0m
14 \e[1m[-b
\e[4m
\e[22mspace
\e[24m
\e[1m] [-h
\e[4m
\e[22mlines
\e[24m
\e[1m] [-j
\e[4m
\e[22mline
\e[24m
\e[1m] [-k
\e[4m
\e[22mkeyfile
\e[24m
\e[1m]
\e[0m
15 \e[1m[-{oO}
\e[4m
\e[22mlogfile
\e[24m
\e[1m] [-p
\e[4m
\e[22mpattern
\e[24m
\e[1m] [-P
\e[4m
\e[22mprompt
\e[24m
\e[1m] [-t
\e[4m
\e[22mtag
\e[24m
\e[1m]
\e[0m
16 \e[1m[-T
\e[4m
\e[22mtagsfile
\e[24m
\e[1m] [-x
\e[4m
\e[22mtab
\e[24m
\e[1m,...] [-y
\e[4m
\e[22mlines
\e[24m
\e[1m] [-[z]
\e[4m
\e[22mlines
\e[24m
\e[1m]
\e[0m
17 \e[1m[-#
\e[4m
\e[22mshift
\e[24m
\e[1m] [+[+]
\e[4m
\e[22mcmd
\e[24m
\e[1m] [--] [
\e[4m
\e[22mfilename
\e[24m
\e[1m]...
\e[0m
18 (See the OPTIONS section for alternate option syntax with long option
23 \e[4mLess
\e[24m is a program similar to
\e[4mmore
\e[24m (1), but which allows backward move-
24 ment in the file as well as forward movement. Also,
\e[4mless
\e[24m does not have
25 to read the entire input file before starting, so with large input
26 files it starts up faster than text editors like
\e[4mvi
\e[24m (1).
\e[4mLess
\e[24m uses
27 termcap (or terminfo on some systems), so it can run on a variety of
28 terminals. There is even limited support for hardcopy terminals. (On
29 a hardcopy terminal, lines which should be printed at the top of the
30 screen are prefixed with a caret.)
32 Commands are based on both
\e[4mmore
\e[24m and
\e[4mvi.
\e[24m Commands may be preceded by a
33 decimal number, called N in the descriptions below. The number is used
34 by some commands, as indicated.
38 In the following descriptions, ^X means control-X. ESC stands for the
39 ESCAPE key; for example ESC-v means the two character sequence
42 h or H Help: display a summary of these commands. If you forget all
43 the other commands, remember this one.
45 SPACE or ^V or f or ^F
46 Scroll forward N lines, default one window (see option -z
47 below). If N is more than the screen size, only the final
48 screenful is displayed. Warning: some systems use ^V as a spe-
49 cial literalization character.
51 z Like SPACE, but if N is specified, it becomes the new window
55 Like SPACE, but scrolls a full screenful, even if it reaches
56 end-of-file in the process.
58 ENTER or RETURN or ^N or e or ^E or j or ^J
59 Scroll forward N lines, default 1. The entire N lines are dis-
60 played, even if N is more than the screen size.
63 Scroll forward N lines, default one half of the screen size. If
64 N is specified, it becomes the new default for subsequent d and
68 Scroll backward N lines, default one window (see option -z
69 below). If N is more than the screen size, only the final
70 screenful is displayed.
72 w Like ESC-v, but if N is specified, it becomes the new window
75 y or ^Y or ^P or k or ^K
76 Scroll backward N lines, default 1. The entire N lines are dis-
77 played, even if N is more than the screen size. Warning: some
78 systems use ^Y as a special job control character.
81 Scroll backward N lines, default one half of the screen size.
82 If N is specified, it becomes the new default for subsequent d
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.)
110 ESC-F Like F, but as soon as a line is found which matches the last
111 search pattern, the terminal bell is rung and forward scrolling
115 Go to line N in the file, default 1 (beginning of file). (Warn-
116 ing: this may be slow if N is large.)
119 Go to line N in the file, default the end of the file. (Warn-
120 ing: this may be slow if N is large, or if N is not specified
121 and standard input, rather than a file, is being read.)
123 p or % Go to a position N percent into the file. N should be between 0
124 and 100, and may contain a decimal point.
126 P Go to the line containing byte offset N in the file.
128 { If a left curly bracket appears in the top line displayed on the
129 screen, the { command will go to the matching right curly
130 bracket. The matching right curly bracket is positioned on the
131 bottom line of the screen. If there is more than one left curly
132 bracket on the top line, a number N may be used to specify the
133 N-th bracket on the line.
135 } If a right curly bracket appears in the bottom line displayed on
136 the screen, the } command will go to the matching left curly
137 bracket. The matching left curly bracket is positioned on the
138 top line of the screen. If there is more than one right curly
139 bracket on the top line, a number N may be used to specify the
140 N-th bracket on the line.
142 ( Like {, but applies to parentheses rather than curly brackets.
144 ) Like }, but applies to parentheses rather than curly brackets.
146 [ Like {, but applies to square brackets rather than curly brack-
149 ] Like }, but applies to square brackets rather than curly brack-
152 ESC-^F Followed by two characters, acts like {, but uses the two char-
153 acters as open and close brackets, respectively. For example,
154 "ESC ^F < >" could be used to go forward to the > which matches
155 the < in the top displayed line.
157 ESC-^B Followed by two characters, acts like }, but uses the two char-
158 acters as open and close brackets, respectively. For example,
159 "ESC ^B < >" could be used to go backward to the < which matches
160 the > in the bottom displayed line.
162 m Followed by any lowercase letter, marks the current position
165 ' (Single quote.) Followed by any lowercase letter, returns to
166 the position which was previously marked with that letter. Fol-
167 lowed by another single quote, returns to the position at which
168 the last "large" movement command was executed. Followed by a ^
169 or $, jumps to the beginning or end of the file respectively.
170 Marks are preserved when a new file is examined, so the ' com-
171 mand can be used to switch between input files.
173 ^X^X Same as single quote.
176 Search forward in the file for the N-th line containing the pat-
177 tern. N defaults to 1. The pattern is a regular expression, as
178 recognized by the regular expression library supplied by your
179 system. The search starts at the first line displayed (but see
180 the -a and -j options, which change this).
182 Certain characters are special if entered at the beginning of
183 the pattern; they modify the type of search rather than become
187 Search for lines which do NOT match the pattern.
190 Search multiple files. That is, if the search reaches
191 the END of the current file without finding a match, the
192 search continues in the next file in the command line
196 Begin the search at the first line of the FIRST file in
197 the command line list, regardless of what is currently
198 displayed on the screen or the settings of the -a or -j
201 ^K Highlight any text which matches the pattern on the cur-
202 rent screen, but don't move to the first match (KEEP cur-
205 ^R Don't interpret regular expression metacharacters; that
206 is, do a simple textual comparison.
209 Search backward in the file for the N-th line containing the
210 pattern. The search starts at the line immediately before the
213 Certain characters are special as in the / command:
216 Search for lines which do NOT match the pattern.
219 Search multiple files. That is, if the search reaches
220 the beginning of the current file without finding a
221 match, the search continues in the previous file in the
225 Begin the search at the last line of the last file in the
226 command line list, regardless of what is currently dis-
227 played on the screen or the settings of the -a or -j
230 ^K As in forward searches.
232 ^R As in forward searches.
240 n Repeat previous search, for N-th line containing the last pat-
241 tern. If the previous search was modified by ^N, the search is
242 made for the N-th line NOT containing the pattern. If the pre-
243 vious search was modified by ^E, the search continues in the
244 next (or previous) file if not satisfied in the current file.
245 If the previous search was modified by ^R, the search is done
246 without using regular expressions. There is no effect if the
247 previous search was modified by ^F or ^K.
249 N Repeat previous search, but in the reverse direction.
251 ESC-n Repeat previous search, but crossing file boundaries. The
252 effect is as if the previous search were modified by *.
254 ESC-N Repeat previous search, but in the reverse direction and cross-
257 ESC-u Undo search highlighting. Turn off highlighting of strings
258 matching the current search pattern. If highlighting is already
259 off because of a previous ESC-u command, turn highlighting back
260 on. Any search command will also turn highlighting back on.
261 (Highlighting can also be disabled by toggling the -G option; in
262 that case search commands do not turn highlighting back on.)
265 Display only lines which match the pattern; lines which do not
266 match the pattern are not displayed. If pattern is empty (if
267 you type & immediately followed by ENTER), any filtering is
268 turned off, and all lines are displayed. While filtering is in
269 effect, an ampersand is displayed at the beginning of the
270 prompt, as a reminder that some lines in the file may be hidden.
272 Certain characters are special as in the / command:
275 Display only lines which do NOT match the pattern.
277 ^R Don't interpret regular expression metacharacters; that
278 is, do a simple textual comparison.
281 Examine a new file. If the filename is missing, the "current"
282 file (see the :n and :p commands below) from the list of files
283 in the command line is re-examined. A percent sign (%) in the
284 filename is replaced by the name of the current file. A pound
285 sign (#) is replaced by the name of the previously examined
286 file. However, two consecutive percent signs are simply
287 replaced with a single percent sign. This allows you to enter a
288 filename that contains a percent sign in the name. Similarly,
289 two consecutive pound signs are replaced with a single pound
290 sign. The filename is inserted into the command line list of
291 files so that it can be seen by subsequent :n and :p commands.
292 If the filename consists of several files, they are all inserted
293 into the list of files and the first one is examined. If the
294 filename contains one or more spaces, the entire filename should
295 be enclosed in double quotes (also see the -" option).
298 Same as :e. Warning: some systems use ^V as a special literal-
299 ization character. On such systems, you may not be able to use
302 :n Examine the next file (from the list of files given in the com-
303 mand line). If a number N is specified, the N-th next file is
306 :p Examine the previous file in the command line list. If a number
307 N is specified, the N-th previous file is examined.
309 :x Examine the first file in the command line list. If a number N
310 is specified, the N-th file in the list is examined.
312 :d Remove the current file from the list of files.
314 t Go to the next tag, if there were more than one matches for the
315 current tag. See the -t option for more details about tags.
317 T Go to the previous tag, if there were more than one matches for
321 Prints some information about the file being viewed, including
322 its name and the line number and byte offset of the bottom line
323 being displayed. If possible, it also prints the length of the
324 file, the number of lines in the file and the percent of the
325 file above the last displayed line.
327 - Followed by one of the command line option letters (see OPTIONS
328 below), this will change the setting of that option and print a
329 message describing the new setting. If a ^P (CONTROL-P) is
330 entered immediately after the dash, the setting of the option is
331 changed but no message is printed. If the option letter has a
332 numeric value (such as -b or -h), or a string value (such as -P
333 or -t), a new value may be entered after the option letter. If
334 no new value is entered, a message describing the current set-
335 ting is printed and nothing is changed.
337 -- Like the - command, but takes a long option name (see OPTIONS
338 below) rather than a single option letter. You must press ENTER
339 or RETURN after typing the option name. A ^P immediately after
340 the second dash suppresses printing of a message describing the
341 new setting, as in the - command.
343 -+ Followed by one of the command line option letters this will
344 reset the option to its default setting and print a message
345 describing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
346 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
347 string-valued options.
349 --+ Like the -+ command, but takes a long option name rather than a
350 single option letter.
352 -! Followed by one of the command line option letters, this will
353 reset the option to the "opposite" of its default setting and
354 print a message describing the new setting. This does not work
355 for numeric or string-valued options.
357 --! Like the -! command, but takes a long option name rather than a
358 single option letter.
360 _ (Underscore.) Followed by one of the command line option let-
361 ters, this will print a message describing the current setting
362 of that option. The setting of the option is not changed.
364 __ (Double underscore.) Like the _ (underscore) command, but takes
365 a long option name rather than a single option letter. You must
366 press ENTER or RETURN after typing the option name.
368 +cmd Causes the specified cmd to be executed each time a new file is
369 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
370 file starting at the end rather than the beginning.
372 V Prints the version number of
\e[4mless
\e[24m being run.
374 q or Q or :q or :Q or ZZ
375 Exits
\e[4mless.
\e[0m
377 The following four commands may or may not be valid, depending on your
378 particular installation.
380 v Invokes an editor to edit the current file being viewed. The
381 editor is taken from the environment variable VISUAL if defined,
382 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
383 ther VISUAL nor EDITOR is defined. See also the discussion of
384 LESSEDIT under the section on PROMPTS below.
387 Invokes a shell to run the shell-command given. A percent sign
388 (%) in the command is replaced by the name of the current file.
389 A pound sign (#) is replaced by the name of the previously exam-
390 ined file. "!!" repeats the last shell command. "!" with no
391 shell command simply invokes a shell. On Unix systems, the
392 shell is taken from the environment variable SHELL, or defaults
393 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
397 <m> represents any mark letter. Pipes a section of the input
398 file to the given shell command. The section of the file to be
399 piped is between the first line on the current screen and the
400 position marked by the letter. <m> may also be ^ or $ to indi-
401 cate beginning or end of file respectively. If <m> is . or new-
402 line, the current screen is piped.
405 Save the input to a file. This only works if the input is a
406 pipe, not an ordinary file.
409 Command line options are described below. Most options may be changed
410 while
\e[4mless
\e[24m is running, via the "-" command.
412 Most options may be given in one of two forms: either a dash followed
413 by a single letter, or two dashes followed by a long option name. A
414 long option name may be abbreviated as long as the abbreviation is
415 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
416 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
417 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
418 from --quit-at-eof. Such option names need only have their first let-
419 ter capitalized; the remainder of the name may be in either case. For
420 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
422 Options are also taken from the environment variable "LESS". For exam-
423 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
424 might tell
\e[4mcsh:
\e[0m
426 setenv LESS "-options"
428 or if you use
\e[4msh:
\e[0m
430 LESS="-options"; export LESS
432 On MS-DOS, you don't need the quotes, but you should replace any per-
433 cent signs in the options string by double percent signs.
435 The environment variable is parsed before the command line, so command
436 line options override the LESS environment variable. If an option
437 appears in the LESS variable, it can be reset to its default value on
438 the command line by beginning the command line option with "-+".
440 For options like -P or -D which take a following string, a dollar sign
441 ($) must be used to signal the end of the string. For example, to set
442 two -D options on MS-DOS, you must have a dollar sign between them,
449 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
450 (the same as the h command). (Depending on how your shell
451 interprets the question mark, it may be necessary to quote the
452 question mark, thus: "-\?".)
454 -a or --search-skip-screen
455 By default, forward searches start at the top of the displayed
456 screen and backwards searches start at the bottom of the dis-
457 played screen (except for repeated searches invoked by the n or
458 N commands, which start after or before the "target" line
459 respectively; see the -j option for more about the target line).
460 The -a option causes forward searches to instead start at the
461 bottom of the screen and backward searches to start at the top
462 of the screen, thus skipping all lines displayed on the screen.
464 -A or --SEARCH-SKIP-SCREEN
465 Causes all forward searches (not just non-repeated searches) to
466 start just after the target line, and all backward searches to
467 start just before the target line. Thus, forward searches will
468 skip part of the displayed screen (from the first line up to and
469 including the target line). Similarly backwards searches will
470 skip the displayed screen from the last line up to and including
471 the target line. This was the default behavior in less versions
474 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
475 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
476 file, in units of kilobytes (1024 bytes). By default 64K of
477 buffer space is used for each file (unless the file is a pipe;
478 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
479 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
480 -1, buffer space is unlimited; that is, the entire file can be
484 By default, when data is read from a pipe, buffers are allocated
485 automatically as needed. If a large amount of data is read from
486 the pipe, this can cause a large amount of memory to be allo-
487 cated. The -B option disables this automatic allocation of buf-
488 fers for pipes, so that only 64K (or the amount of space speci-
489 fied by the -b option) is used for the pipe. Warning: use of -B
490 can result in erroneous display, since only the most recently
491 viewed part of the piped data is kept in memory; any earlier
495 Causes full screen repaints to be painted from the top line
496 down. By default, full screen repaints are done by scrolling
497 from the bottom of the screen.
500 Same as -c, for compatibility with older versions of
\e[4mless.
\e[0m
503 The -d option suppresses the error message normally displayed if
504 the terminal is dumb; that is, lacks some important capability,
505 such as the ability to clear the screen or scroll backward. The
506 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
509 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
510 [MS-DOS only] Sets the color of the text displayed.
\e[1mx
\e[22mis a sin-
511 gle character which selects the type of text whose color is
512 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
513 \e[4mcolor
\e[24m is a pair of numbers separated by a period. The first
514 number selects the foreground color and the second selects the
515 background color of the text. A single number
\e[4mN
\e[24m is the same as
516 \e[4mN.M
\e[24m, where
\e[4mM
\e[24m is the normal background color.
520 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
521 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
525 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
529 Forces non-regular files to be opened. (A non-regular file is a
530 directory or a device special file.) Also suppresses the warn-
531 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
532 refuse to open non-regular files. Note that some operating sys-
533 tems will not allow directories to be read, even if -f is set.
535 -F or --quit-if-one-screen
536 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
537 played on the first screen.
539 -g or --hilite-search
540 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
541 search command. The -g option changes this behavior to high-
542 light only the particular string which was found by the last
543 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
546 -G or --HILITE-SEARCH
547 The -G option suppresses all highlighting of strings found by
550 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
551 Specifies a maximum number of lines to scroll backward. If it
552 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
553 repainted in a forward direction instead. (If the terminal does
554 not have the ability to scroll backward, -h0 is implied.)
557 Causes searches to ignore case; that is, uppercase and lowercase
558 are considered identical. This option is ignored if any upper-
559 case letters appear in the search pattern; in other words, if a
560 pattern contains uppercase letters, then that search does not
564 Like -i, but searches ignore case even if the pattern contains
567 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
568 Specifies a line on the screen where the "target" line is to be
569 positioned. The target line is the line specified by any com-
570 mand to search for a pattern, jump to a line number, jump to a
571 file percentage or jump to a tag. The screen line may be speci-
572 fied by a number: the top line on the screen is 1, the next is
573 2, and so on. The number may be negative to specify a line rel-
574 ative to the bottom of the screen: the bottom line on the screen
575 is -1, the second to the bottom is -2, and so on. Alternately,
576 the screen line may be specified as a fraction of the height of
577 the screen, starting with a decimal point: .5 is in the middle
578 of the screen, .3 is three tenths down from the first line, and
579 so on. If the line is specified as a fraction, the actual line
580 number is recalculated if the terminal window is resized, so
581 that the target line remains at the specified fraction of the
582 screen height. If any form of the -j option is used, forward
583 searches begin at the line immediately after the target line,
584 and backward searches begin at the target line, unless changed
585 by -a or -A. For example, if "-j4" is used, the target line is
586 the fourth line on the screen, so forward searches begin at the
587 fifth line on the screen.
589 -J or --status-column
590 Displays a status column at the left edge of the screen. The
591 status column shows the lines that matched the current search.
592 The status column is also used if the -w or -W option is in
595 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
596 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[0m
597 (1) file. Multiple -k options may be specified. If the LESSKEY
598 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
599 file is found in a standard place (see KEY BINDINGS), it is also
600 used as a
\e[4mlesskey
\e[24m file.
603 Causes
\e[4mless
\e[24m to exit immediately (with status 2) when an inter-
604 rupt character (usually ^C) is typed. Normally, an interrupt
605 character causes
\e[4mless
\e[24m to stop whatever it is doing and return to
606 its command prompt. Note that use of this option makes it
607 impossible to return to the command prompt from the "F" command.
610 Ignore the LESSOPEN environment variable (see the INPUT PRE-
611 PROCESSOR section below). This option can be set from within
612 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
613 to the file which is currently open.
616 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
617 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
620 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore.
\e[0m
623 Suppresses line numbers. The default (to use line numbers) may
624 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
625 very large input file. Suppressing line numbers with the -n
626 option will avoid this problem. Using line numbers means: the
627 line number will be displayed in the verbose prompt and in the =
628 command, and the v command will pass the current line number to
629 the editor (see also the discussion of LESSEDIT in PROMPTS
633 Causes a line number to be displayed at the beginning of each
636 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
637 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
638 viewed. This applies only when the input file is a pipe, not an
639 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
640 confirmation before overwriting it.
642 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
643 The -O option is like -o, but it will overwrite an existing file
644 without asking for confirmation.
646 If no log file has been specified, the -o and -O options can be
647 used from within
\e[4mless
\e[24m to specify a log file. Without a file
648 name, they will simply report the name of the log file. The "s"
649 command is equivalent to specifying -o from within
\e[4mless.
\e[0m
651 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
652 The -p option on the command line is equivalent to specifying
653 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
654 rence of
\e[4mpattern
\e[24m in the file.
656 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
657 Provides a way to tailor the three prompt styles to your own
658 preference. This option would normally be put in the LESS envi-
659 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
660 mand. Such an option must either be the last option in the LESS
661 variable, or be terminated by a dollar sign. -Ps followed by a
662 string changes the default (short) prompt to that string. -Pm
663 changes the medium (-m) prompt. -PM changes the long (-M)
664 prompt. -Ph changes the prompt for the help screen. -P=
665 changes the message printed by the = command. -Pw changes the
666 message printed while waiting for data (in the F command). All
667 prompt strings consist of a sequence of letters and special
668 escape sequences. See the section on PROMPTS for more details.
670 -q or --quiet or --silent
671 Causes moderately "quiet" operation: the terminal bell is not
672 rung if an attempt is made to scroll past the end of the file or
673 before the beginning of the file. If the terminal has a "visual
674 bell", it is used instead. The bell will be rung on certain
675 other errors, such as typing an invalid character. The default
676 is to ring the terminal bell in all such cases.
678 -Q or --QUIET or --SILENT
679 Causes totally "quiet" operation: the terminal bell is never
682 -r or --raw-control-chars
683 Causes "raw" control characters to be displayed. The default is
684 to display control characters using the caret notation; for
685 example, a control-A (octal 001) is displayed as "^A". Warning:
686 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
687 appearance of the screen (since this depends on how the screen
688 responds to each type of control character). Thus, various dis-
689 play problems may result, such as long lines being split in the
692 -R or --RAW-CONTROL-CHARS
693 Like -r, but only ANSI "color" escape sequences are output in
694 "raw" form. Unlike -r, the screen appearance is maintained cor-
695 rectly in most cases. ANSI "color" escape sequences are
696 sequences of the form:
700 where the "..." is zero or more color specification characters
701 For the purpose of keeping track of screen appearance, ANSI
702 color escape sequences are assumed to not move the cursor. You
703 can make
\e[4mless
\e[24m think that characters other than "m" can end ANSI
704 color escape sequences by setting the environment variable
705 LESSANSIENDCHARS to the list of characters which can end a color
706 escape sequence. And you can make
\e[4mless
\e[24m think that characters
707 other than the standard ones may appear between the ESC and the
708 m by setting the environment variable LESSANSIMIDCHARS to the
709 list of characters which can appear.
711 -s or --squeeze-blank-lines
712 Causes consecutive blank lines to be squeezed into a single
713 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
715 -S or --chop-long-lines
716 Causes lines longer than the screen width to be chopped (trun-
717 cated) rather than wrapped. That is, the portion of a long line
718 that does not fit in the screen width is not shown. The default
719 is to wrap long lines; that is, display the remainder on the
722 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
723 The -t option, followed immediately by a TAG, will edit the file
724 containing that tag. For this to work, tag information must be
725 available; for example, there may be a file in the current
726 directory called "tags", which was previously built by
\e[4mctags
\e[24m (1)
727 or an equivalent command. If the environment variable LESSGLOB-
728 ALTAGS is set, it is taken to be the name of a command compati-
729 ble with
\e[4mglobal
\e[24m (1), and that command is executed to find the
730 tag. (See http://www.gnu.org/software/global/global.html). The
731 -t option may also be specified from within
\e[4mless
\e[24m (using the -
732 command) as a way of examining a new file. The command ":t" is
733 equivalent to specifying -t from within
\e[4mless.
\e[0m
735 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
736 Specifies a tags file to be used instead of "tags".
738 -u or --underline-special
739 Causes backspaces and carriage returns to be treated as print-
740 able characters; that is, they are sent to the terminal when
741 they appear in the input.
743 -U or --UNDERLINE-SPECIAL
744 Causes backspaces, tabs and carriage returns to be treated as
745 control characters; that is, they are handled as specified by
748 By default, if neither -u nor -U is given, backspaces which
749 appear adjacent to an underscore character are treated spe-
750 cially: the underlined text is displayed using the terminal's
751 hardware underlining capability. Also, backspaces which appear
752 between two identical characters are treated specially: the
753 overstruck text is printed using the terminal's hardware bold-
754 face capability. Other backspaces are deleted, along with the
755 preceding character. Carriage returns immediately followed by a
756 newline are deleted. Other carriage returns are handled as
757 specified by the -r option. Text which is overstruck or under-
758 lined can be searched for if neither -u nor -U is in effect.
761 Displays the version number of
\e[4mless.
\e[0m
763 -w or --hilite-unread
764 Temporarily highlights the first "new" line after a forward
765 movement of a full page. The first "new" line is the line imme-
766 diately following the line previously at the bottom of the
767 screen. Also highlights the target line after a g or p command.
768 The highlight is removed at the next command which causes move-
769 ment. The entire line is highlighted, unless the -J option is
770 in effect, in which case only the status column is highlighted.
772 -W or --HILITE-UNREAD
773 Like -w, but temporarily highlights the first new line after any
774 forward movement command larger than one line.
776 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
777 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
778 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
779 specified, tab stops are set at those positions, and then con-
780 tinue with the same spacing as the last two. For example,
781 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The
782 default for
\e[4mn
\e[24m is 8.
785 Disables sending the termcap initialization and deinitialization
786 strings to the terminal. This is sometimes desirable if the
787 deinitialization string does something unnecessary, like clear-
790 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
791 Specifies a maximum number of lines to scroll forward. If it is
792 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is
793 repainted instead. The -c or -C option may be used to repaint
794 from the top of the screen if desired. By default, any forward
795 movement causes scrolling.
797 -[z]
\e[4mn
\e[24m or --window=
\e[4mn
\e[0m
798 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The
799 default is one screenful. The z and w commands can also be used
800 to change the window size. The "z" may be omitted for compati-
801 bility with some versions of
\e[4mmore.
\e[24m If the number
\e[4mn
\e[24m is negative,
802 it indicates
\e[4mn
\e[24m lines less than the current screen size. For
803 example, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling win-
804 dow to 20 lines. If the screen is resized to 40 lines, the
805 scrolling window automatically changes to 36 lines.
807 -
\e[4m"cc
\e[24m or --quotes=
\e[4mcc
\e[0m
808 Changes the filename quoting character. This may be necessary
809 if you are trying to name a file which contains both spaces and
810 quote characters. Followed by a single character, this changes
811 the quote character to that character. Filenames containing a
812 space should then be surrounded by that character rather than by
813 double quotes. Followed by two characters, changes the open
814 quote to the first character, and the close quote to the second
815 character. Filenames containing a space should then be preceded
816 by the open quote character and followed by the close quote
817 character. Note that even after the quote characters are
818 changed, this option remains -" (a dash followed by a double
822 Normally lines after end of file are displayed as a single tilde
823 (~). This option causes lines after end of file to be displayed
827 Specifies the default number of positions to scroll horizontally
828 in the RIGHTARROW and LEFTARROW commands. If the number speci-
829 fied is zero, it sets the default number of positions to one
830 half of the screen width. Alternately, the number may be speci-
831 fied as a fraction of the width of the screen, starting with a
832 decimal point: .5 is half of the screen width, .3 is three
833 tenths of the screen width, and so on. If the number is speci-
834 fied as a fraction, the actual number of scroll positions is
835 recalculated if the terminal window is resized, so that the
836 actual scroll remains at the specified fraction of the screen
840 Disables sending the keypad initialization and deinitialization
841 strings to the terminal. This is sometimes useful if the keypad
842 strings make the numeric keypad behave in an undesirable manner.
845 Normally, if the input file is renamed while an F command is
846 executing,
\e[4mless
\e[24m will continue to display the contents of the
847 original file despite its name change. If --follow-name is
848 specified, during an F command
\e[4mless
\e[24m will periodically attempt to
849 reopen the file by name. If the reopen succeeds and the file is
850 a different file from the original (which means that a new file
851 has been created with the same name as the original (now
852 renamed) file),
\e[4mless
\e[24m will display the contents of that new file.
854 -- A command line argument of "--" marks the end of option argu-
855 ments. Any arguments following this are interpreted as file-
856 names. This can be useful when viewing a file whose name begins
859 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
860 option is taken to be an initial command to
\e[4mless.
\e[24m For example,
861 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
862 beginning, and +/xyz tells it to start at the first occurrence
863 of "xyz" in the file. As a special case, +<number> acts like
864 +<number>g; that is, it starts the display at the specified line
865 number (however, see the caveat under the "g" command above).
866 If the option starts with ++, the initial command applies to
867 every file being viewed, not just the first one. The + command
868 described previously may also be used to set (or change) an ini-
869 tial command for every file.
872 \e[1mLINE EDITING
\e[0m
873 When entering command line at the bottom of the screen (for example, a
874 filename for the :e command, or the pattern for a search command), cer-
875 tain keys can be used to manipulate the command line. Most commands
876 have an alternate form in [ brackets ] which can be used if a key does
877 not exist on a particular keyboard. (Note that the forms beginning
878 with ESC do not work in some MS-DOS and Windows systems because ESC is
879 the line erase character.) Any of these special keys may be entered
880 literally by preceding it with the "literal" character, either ^V or
881 ^A. A backslash itself may also be entered literally by entering two
885 Move the cursor one space to the left.
888 Move the cursor one space to the right.
890 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
891 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
892 sor one word to the left.
894 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
895 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
896 sor one word to the right.
899 Move the cursor to the beginning of the line.
902 Move the cursor to the end of the line.
905 Delete the character to the left of the cursor, or cancel the
906 command if the command line is empty.
909 Delete the character under the cursor.
911 ^BACKSPACE [ ESC-BACKSPACE ]
912 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
913 word to the left of the cursor.
915 ^DELETE [ ESC-X or ESC-DELETE ]
916 (That is, CONTROL and DELETE simultaneously.) Delete the word
920 Retrieve the previous command line. If you first enter some
921 text and then press UPARROW, it will retrieve the previous com-
922 mand which begins with that text.
925 Retrieve the next command line. If you first enter some text
926 and then press DOWNARROW, it will retrieve the next command
927 which begins with that text.
929 TAB Complete the partial filename to the left of the cursor. If it
930 matches more than one filename, the first match is entered into
931 the command line. Repeated TABs will cycle thru the other
932 matching filenames. If the completed filename is a directory, a
933 "/" is appended to the filename. (On MS-DOS systems, a "\" is
934 appended.) The environment variable LESSSEPARATOR can be used
935 to specify a different character to append to a directory name.
938 Like, TAB, but cycles in the reverse direction thru the matching
941 ^L Complete the partial filename to the left of the cursor. If it
942 matches more than one filename, all matches are entered into the
943 command line (if they fit).
945 ^U (Unix and OS/2) or ESC (MS-DOS)
946 Delete the entire command line, or cancel the command if the
947 command line is empty. If you have changed your line-kill char-
948 acter in Unix to something other than ^U, that character is used
951 ^G Delete the entire command line and return to the main prompt.
954 \e[1mKEY BINDINGS
\e[0m
955 You may define your own
\e[4mless
\e[24m commands by using the program
\e[4mlesskey
\e[24m (1)
956 to create a lesskey file. This file specifies a set of command keys
957 and an action associated with each key. You may also use
\e[4mlesskey
\e[24m to
958 change the line-editing keys (see LINE EDITING), and to set environment
959 variables. If the environment variable LESSKEY is set,
\e[4mless
\e[24m uses that
960 as the name of the lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard
961 place for the lesskey file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey
962 file called "$HOME/.less". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks
963 for a lesskey file called "$HOME/_less", and if it is not found there,
964 then looks for a lesskey file called "_less" in any directory specified
965 in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for a
966 lesskey file called "$HOME/less.ini", and if it is not found, then
967 looks for a lesskey file called "less.ini" in any directory specified
968 in the INIT environment variable, and if it not found there, then looks
969 for a lesskey file called "less.ini" in any directory specified in the
970 PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for more
973 A system-wide lesskey file may also be set up to provide key bindings.
974 If a key is defined in both a local lesskey file and in the system-wide
975 file, key bindings in the local file take precedence over those in the
976 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
977 \e[4mless
\e[24m uses that as the name of the system-wide lesskey file. Otherwise,
978 \e[4mless
\e[24m looks in a standard place for the system-wide lesskey file: On
979 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
980 (However, if
\e[4mless
\e[24m was built with a different sysconf directory than
981 /usr/local/etc, that directory is where the sysless file is found.) On
982 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys-
983 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
986 \e[1mINPUT PREPROCESSOR
\e[0m
987 You may define an "input preprocessor" for
\e[4mless.
\e[24m Before
\e[4mless
\e[24m opens a
988 file, it first gives your input preprocessor a chance to modify the way
989 the contents of the file are displayed. An input preprocessor is sim-
990 ply an executable program (or shell script), which writes the contents
991 of the file to a different file, called the replacement file. The con-
992 tents of the replacement file are then displayed in place of the con-
993 tents of the original file. However, it will appear to the user as if
994 the original file is opened; that is,
\e[4mless
\e[24m will display the original
995 filename as the name of the current file.
997 An input preprocessor receives one command line argument, the original
998 filename, as entered by the user. It should create the replacement
999 file, and when finished, print the name of the replacement file to its
1000 standard output. If the input preprocessor does not output a replace-
1001 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
1002 processor is not called when viewing standard input. To set up an
1003 input preprocessor, set the LESSOPEN environment variable to a command
1004 line which will invoke your input preprocessor. This command line
1005 should include one occurrence of the string "%s", which will be
1006 replaced by the filename when the input preprocessor command is
1009 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
1010 gram, called the input postprocessor, which may perform any desired
1011 clean-up action (such as deleting the replacement file created by
1012 LESSOPEN). This program receives two command line arguments, the orig-
1013 inal filename as entered by the user, and the name of the replacement
1014 file. To set up an input postprocessor, set the LESSCLOSE environment
1015 variable to a command line which will invoke your input postprocessor.
1016 It may include two occurrences of the string "%s"; the first is
1017 replaced with the original name of the file and the second with the
1018 name of the replacement file, which was output by LESSOPEN.
1020 For example, on many Unix systems, these two scripts will allow you to
1021 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1027 if [ -s /tmp/less.$$ ]; then
1039 To use these scripts, put them both where they can be executed and set
1040 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1041 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1042 types of compressed files, and so on.
1044 It is also possible to set up an input preprocessor to pipe the file
1045 data directly to
\e[4mless,
\e[24m rather than putting the data into a replacement
1046 file. This avoids the need to decompress the entire file before start-
1047 ing to view it. An input preprocessor that works this way is called an
1048 input pipe. An input pipe, instead of writing the name of a replace-
1049 ment file on its standard output, writes the entire contents of the
1050 replacement file on its standard output. If the input pipe does not
1051 write any characters on its standard output, then there is no replace-
1052 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1053 pipe, make the first character in the LESSOPEN environment variable a
1054 vertical bar (|) to signify that the input preprocessor is an input
1057 For example, on many Unix systems, this script will work like the pre-
1058 vious example scripts:
1063 *.Z) uncompress -c $1 2>/dev/null
1069 To use this script, put it where it can be executed and set
1070 LESSOPEN="|lesspipe.sh %s".
1072 Note that a preprocessor cannot output an empty file, since that is
1073 interpreted as meaning there is no replacement, and the original file
1074 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1075 exit status of the script becomes meaningful. If the exit status is
1076 zero, the output is considered to be replacement text, even if it
1077 empty. If the exit status is nonzero, any output is ignored and the
1078 original file is used. For compatibility with previous versions of
1079 \e[4mless,
\e[24m if LESSOPEN starts with only one vertical bar, the exit status of
1080 the preprocessor is ignored.
1082 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1083 it is usually not necessary since there is no replacement file to clean
1084 up. In this case, the replacement file name passed to the LESSCLOSE
1085 postprocessor is "-".
1087 For compatibility with previous versions of
\e[4mless,
\e[24m the input preproces-
1088 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1089 the first character of LESSOPEN is a dash (-), the input preprocessor
1090 is used on standard input as well as other files. In this case, the
1091 dash is not considered to be part of the preprocessor command. If
1092 standard input is being viewed, the input preprocessor is passed a file
1093 name consisting of a single dash. Similarly, if the first two charac-
1094 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1095 and a dash (||-), the input pipe is used on standard input as well as
1096 other files. Again, in this case the dash is not considered to be part
1097 of the input pipe command.
1100 \e[1mNATIONAL CHARACTER SETS
\e[0m
1101 There are three types of characters in the input file:
1104 can be displayed directly to the screen.
1107 should not be displayed directly, but are expected to be found
1108 in ordinary text files (such as backspace and tab).
1111 should not be displayed directly and are not expected to be
1112 found in text files.
1114 A "character set" is simply a description of which characters are to be
1115 considered normal, control, and binary. The LESSCHARSET environment
1116 variable may be used to select a character set. Possible values for
1119 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1120 with values between 32 and 126 are normal, and all others are
1124 Selects an ISO 8859 character set. This is the same as ASCII,
1125 except characters between 160 and 255 are treated as normal
1128 latin1 Same as iso8859.
1130 latin9 Same as iso8859.
1132 dos Selects a character set appropriate for MS-DOS.
1134 ebcdic Selects an EBCDIC character set.
1137 Selects an EBCDIC character set used by OS/390 Unix Services.
1138 This is the EBCDIC analogue of latin1. You get similar results
1139 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1142 koi8-r Selects a Russian character set.
1144 next Selects a character set appropriate for NeXT computers.
1146 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1147 UTF-8 is special in that it supports multi-byte characters in
1148 the input file. It is the only character set that supports
1149 multi-byte characters.
1152 Selects a character set appropriate for Microsoft Windows (cp
1155 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1156 other than the ones definable by LESSCHARSET. In this case, the envi-
1157 ronment variable LESSCHARDEF can be used to define a character set. It
1158 should be set to a string where each character in the string represents
1159 one character in the character set. The character "." is used for a
1160 normal character, "c" for control, and "b" for binary. A decimal num-
1161 ber may be used for repetition. For example, "bccc4b." would mean
1162 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1163 binary, and 8 is normal. All characters after the last are taken to be
1164 the same as the last, so characters 9 through 255 would be normal.
1165 (This is an example, and does not necessarily represent any real char-
1168 This table shows the value of LESSCHARDEF which is equivalent to each
1169 of the possible values for LESSCHARSET:
1171 ascii 8bcccbcc18b95.b
1172 dos 8bcccbcc12bc5b95.b.
1173 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1174 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1175 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1177 iso8859 8bcccbcc18b95.33b.
1178 koi8-r 8bcccbcc18b95.b128.
1179 latin1 8bcccbcc18b95.33b.
1180 next 8bcccbcc18b95.bb125.bb
1182 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1183 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1184 LANG environment variables, then the default character set is utf-8.
1186 If that string is not found, but your system supports the
\e[4msetlocale
\e[0m
1187 interface,
\e[4mless
\e[24m will use setlocale to determine the character set.
1188 setlocale is controlled by setting the LANG or LC_CTYPE environment
1191 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1192 character set is latin1.
1194 Control and binary characters are displayed in standout (reverse
1195 video). Each such character is displayed in caret notation if possible
1196 (e.g. ^A for control-A). Caret notation is used only if inverting the
1197 0100 bit results in a normal printable character. Otherwise, the char-
1198 acter is displayed as a hex number in angle brackets. This format can
1199 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1200 may begin with a "*" and one character to select the display attribute:
1201 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1202 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1203 attribute is assumed. The remainder of LESSBINFMT is a string which
1204 may include one printf-style escape sequence (a % followed by x, X, o,
1205 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1206 are displayed in underlined hexadecimal surrounded by brackets. The
1207 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1208 result of expanding the character via LESSBINFMT must be less than 31
1211 When the character set is utf-8, the LESSUTFBINFMT environment variable
1212 acts similarly to LESSBINFMT but it applies to Unicode code points that
1213 were successfully decoded but are unsuitable for display (e.g., unas-
1214 signed code points). Its default value is "<U+%04lX>". Note that
1215 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1216 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1217 LESSBINFMT so its setting, if any, will have priority. Problematic
1218 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1219 complete but non-shortest form sequence, illegal octets, and stray
1220 trailing octets) are displayed individually using LESSBINFMT so as to
1221 facilitate diagnostic of how the UTF-8 file is ill-formed.
1225 The -P option allows you to tailor the prompt to your preference. The
1226 string given to the -P option replaces the specified prompt string.
1227 Certain characters in the string are interpreted specially. The prompt
1228 mechanism is rather complicated to provide flexibility, but the ordi-
1229 nary user need not understand the details of constructing personalized
1232 A percent sign followed by a single character is expanded according to
1233 what the following character is:
1235 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1236 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1237 ifies the line whose byte offset is to be used. If the charac-
1238 ter is a "t", the byte offset of the top line in the display is
1239 used, an "m" means use the middle line, a "b" means use the bot-
1240 tom line, a "B" means use the line just after the bottom line,
1241 and a "j" means use the "target" line, as specified by the -j
1244 %B Replaced by the size of the current input file.
1246 %c Replaced by the column number of the text appearing in the first
1247 column of the screen.
1249 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1250 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1252 %D Replaced by the number of pages in the input file, or equiva-
1253 lently, the page number of the last line in the input file.
1255 %E Replaced by the name of the editor (from the VISUAL environment
1256 variable, or the EDITOR environment variable if VISUAL is not
1257 defined). See the discussion of the LESSEDIT feature below.
1259 %f Replaced by the name of the current input file.
1261 %F Replaced by the last component of the name of the current input
1264 %i Replaced by the index of the current file in the list of input
1267 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1268 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1270 %L Replaced by the line number of the last line in the input file.
1272 %m Replaced by the total number of input files.
1274 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1275 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1278 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1279 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1284 %t Causes any trailing spaces to be removed. Usually used at the
1285 end of the string, but may appear anywhere.
1287 %x Replaced by the name of the next input file in the list.
1289 If any item is unknown (for example, the file size if input is a pipe),
1290 a question mark is printed instead.
1292 The format of the prompt string can be changed depending on certain
1293 conditions. A question mark followed by a single character acts like
1294 an "IF": depending on the following character, a condition is evalu-
1295 ated. If the condition is true, any characters following the question
1296 mark and condition character, up to a period, are included in the
1297 prompt. If the condition is false, such characters are not included.
1298 A colon appearing between the question mark and the period can be used
1299 to establish an "ELSE": any characters between the colon and the period
1300 are included in the string if and only if the IF condition is false.
1301 Condition characters (which follow a question mark) may be:
1303 ?a True if any characters have been included in the prompt so far.
1305 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1307 ?B True if the size of current input file is known.
1309 ?c True if the text is horizontally shifted (%c is not zero).
1311 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1313 ?e True if at end-of-file.
1315 ?f True if there is an input filename (that is, if input is not a
1318 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1320 ?L True if the line number of the last line in the file is known.
1322 ?m True if there is more than one input file.
1324 ?n True if this is the first prompt in a new input file.
1326 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1327 offsets, of the specified line is known.
1329 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1330 numbers, of the specified line is known.
1334 ?x True if there is a next input file (that is, if the current
1335 input file is not the last one).
1337 Any characters other than the special ones (question mark, colon,
1338 period, percent, and backslash) become literally part of the prompt.
1339 Any of the special characters may be included in the prompt literally
1340 by preceding it with a backslash.
1344 ?f%f:Standard input.
1346 This prompt prints the filename, if known; otherwise the string "Stan-
1349 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1351 This prompt would print the filename, if known. The filename is fol-
1352 lowed by the line number, if known, otherwise the percent if known,
1353 otherwise the byte offset if known. Otherwise, a dash is printed.
1354 Notice how each question mark has a matching period, and how the %
1355 after the %pt is included literally by escaping it with a backslash.
1357 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t
1359 This prints the filename if this is the first prompt in a file, fol-
1360 lowed by the "file N of N" message if there is more than one input
1361 file. Then, if we are at end-of-file, the string "(END)" is printed
1362 followed by the name of the next file, if there is one. Finally, any
1363 trailing spaces are truncated. This is the default prompt. For refer-
1364 ence, here are the defaults for the other two prompts (-m and -M
1365 respectively). Each is broken into two lines here for readability
1368 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.:
1369 ?pB%pB\%:byte %bB?s/%s...%t
1371 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. :
1372 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1374 And here is the default message produced by the = command:
1376 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. .
1377 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1379 The prompt expansion features are also used for another purpose: if an
1380 environment variable LESSEDIT is defined, it is used as the command to
1381 be executed when the v command is invoked. The LESSEDIT string is
1382 expanded in the same way as the prompt strings. The default value for
1387 Note that this expands to the editor name, followed by a + and the line
1388 number, followed by the file name. If your editor does not accept the
1389 "+linenumber" syntax, or has other differences in invocation syntax,
1390 the LESSEDIT variable can be changed to modify this default.
1394 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1395 "secure" mode. This means these features are disabled:
1401 :e the examine command.
1403 v the editing command
1407 -k use of lesskey files
1409 -t use of tags files
1411 metacharacters in filenames, such as *
1413 filename completion (TAB, ^L)
1415 Less can also be compiled to be permanently in "secure" mode.
1418 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1419 If the environment variable LESS_IS_MORE is set to 1, or if the program
1420 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1421 formance with the POSIX "more" command specification. In this mode,
1422 less behaves differently in these ways:
1424 The -e option works differently. If the -e option is not set,
\e[4mless
\e[0m
1425 behaves as if the -E option were set. If the -e option is set,
\e[4mless
\e[0m
1426 behaves as if the -e and -F options were set.
1428 The -m option works differently. If the -m option is not set, the
1429 medium prompt is used, and it is prefixed with the string "--More--".
1430 If the -m option is set, the short prompt is used.
1432 The -n option acts like the -z option. The normal behavior of the -n
1433 option is unavailable in this mode.
1435 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1436 than a search pattern.
1438 The LESS environment variable is ignored, and the MORE environment
1439 variable is used in its place.
1442 \e[1mENVIRONMENT VARIABLES
\e[0m
1443 Environment variables may be specified either in the system environment
1444 as usual, or in a
\e[4mlesskey
\e[24m (1) file. If environment variables are
1445 defined in more than one place, variables defined in a local lesskey
1446 file take precedence over variables defined in the system environment,
1447 which take precedence over variables defined in the system-wide lesskey
1451 Sets the number of columns on the screen. Takes precedence over
1452 the number of columns specified by the TERM variable. (But if
1453 you have a windowing system which supports TIOCGWINSZ or
1454 WIOCGETD, the window system's idea of the screen size takes
1455 precedence over the LINES and COLUMNS environment variables.)
1457 EDITOR The name of the editor (used for the v command).
1459 HOME Name of the user's home directory (used to find a lesskey file
1460 on Unix and OS/2 systems).
1463 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1464 ables is the name of the user's home directory if the HOME vari-
1465 able is not set (only in the Windows version).
1467 INIT Name of the user's init directory (used to find a lesskey file
1470 LANG Language for determining the character set.
1473 Language for determining the character set.
1475 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1478 Characters which may end an ANSI color escape sequence (default
1482 Characters which may appear between the ESC character and the
1483 end character in an ANSI color escape sequence (default
1484 "0123456789;[?!"'#%()*+ ".
1487 Format for displaying non-printable, non-control characters.
1490 Defines a character set.
1493 Selects a predefined character set.
1496 Command line to invoke the (optional) input-postprocessor.
1499 Name of the lessecho program (default "lessecho"). The lessecho
1500 program is needed to expand metacharacters, such as * and ?, in
1501 filenames on Unix systems.
1504 Editor prototype string (used for the v command). See discus-
1508 Name of the command used by the -t option to find global tags.
1509 Normally should be set to "global" if your system has the
\e[4mglobal
\e[0m
1510 (1) command. If not set, global tags are not used.
1513 Name of the history file used to remember search commands and
1514 shell commands between invocations of
\e[4mless.
\e[24m If set to "-" or
1515 "/dev/null", a history file is not used. The default is
1516 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1517 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1521 The maximum number of commands to save in the history file. The
1525 Name of the default lesskey(1) file.
1528 Name of the default system-wide lesskey(1) file.
1531 List of characters which are considered "metacharacters" by the
1535 Prefix which less will add before each metacharacter in a com-
1536 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1537 commands containing metacharacters will not be passed to the
1541 Command line to invoke the (optional) input-preprocessor.
1544 Runs less in "secure" mode. See discussion under SECURITY.
1547 String to be appended to a directory name in filename comple-
1551 Format for displaying non-printable Unicode code points.
1554 Emulate the
\e[4mmore
\e[24m (1) command.
1556 LINES Sets the number of lines on the screen. Takes precedence over
1557 the number of lines specified by the TERM variable. (But if you
1558 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1559 the window system's idea of the screen size takes precedence
1560 over the LINES and COLUMNS environment variables.)
1562 MORE Options which are passed to
\e[4mless
\e[24m automatically when running in
1563 \e[4mmore
\e[24m compatible mode.
1565 PATH User's search path (used to find a lesskey file on MS-DOS and
1568 SHELL The shell used to execute the ! command, as well as to expand
1571 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1573 VISUAL The name of the editor (used for the v command).
1581 Copyright (C) 1984-2012 Mark Nudelman
1583 less is part of the GNU project and is free software. You can redis-
1584 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1585 eral Public License as published by the Free Software Foundation; or
1586 (2) the Less License. See the file README in the less distribution for
1587 more details regarding redistribution. You should have received a copy
1588 of the GNU General Public License along with the source for less; see
1589 the file COPYING. If not, write to the Free Software Foundation, 59
1590 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1591 have received a copy of the Less License; see the file LICENSE.
1593 less is distributed in the hope that it will be useful, but WITHOUT ANY
1594 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1595 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1600 Mark Nudelman <bug-less@gnu.org>
1601 Send bug reports or comments to bug-less@gnu.org.
1602 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1603 of known bugs in less.
1604 For more information, see the less homepage at
1605 http://www.greenwoodsoftware.com/less.
1609 Version 451: 21 Jul 2012 LESS(1)