1LESS(1) General Commands Manual LESS(1)
2
6 less - opposite of more
7
9 less -?
10 less --help
11 less -V
12 less --version
13 less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
14 [-b space] [-h lines] [-j line] [-k keyfile]
15 [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
16 [-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
17 [-# shift] [+[+]cmd] [--] [filename]...
18 (See the OPTIONS section for alternate option syntax with long option
19 names.)
20
23 Less is a program similar to more (1), but which allows backward move‐
24 ment in the file as well as forward movement. Also, less 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 vi (1). Less 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.)
31 Commands are based on both more and vi. 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.
35
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
40 "ESCAPE", then "v".
41 h or H Help: display a summary of these commands. If you forget all
43 the other commands, remember this one.
44 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.
50 z Like SPACE, but if N is specified, it becomes the new window
52 size.
53 ESC-SPACE
55 Like SPACE, but scrolls a full screenful, even if it reaches
56 end-of-file in the process.
57 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.
61 d or ^D
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
65 u commands.
66 b or ^B or ESC-v
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.
71 w Like ESC-v, but if N is specified, it becomes the new window
73 size.
74 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.
79 u or ^U
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
83 and u commands.
84 J Like j, but continues to scroll beyond the end of the file.
86 K or Y Like k, but continues to scroll beyond the beginning of the
88 file.
89 ESC-) or RIGHTARROW
91 Scroll horizontally right N characters, default half the screen
92 width (see the -# option). If a number N is specified, it
93 becomes the default for future RIGHTARROW and LEFTARROW com‐
94 mands. While the text is scrolled, it acts as though the -S
95 option (chop lines) were in effect.
96 ESC-( or LEFTARROW
98 Scroll horizontally left N characters, default half the screen
99 width (see the -# option). If a number N is specified, it
100 becomes the default for future RIGHTARROW and LEFTARROW com‐
101 mands.
102 ESC-} or ^RIGHTARROW
104 Scroll horizontally right to show the end of the longest dis‐
105 played line.
106 ESC-{ or ^LEFTARROW
108 Scroll horizontally left back to the first column.
109 r or ^R or ^L
111 Repaint the screen.
112 R Repaint the screen, discarding any buffered input. Useful if
114 the file is changing while it is being viewed.
115 F Scroll forward, and keep trying to read when the end of file is
117 reached. Normally this command would be used when already at
118 the end of the file. It is a way to monitor the tail of a file
119 which is growing while it is being viewed. (The behavior is
120 similar to the "tail -f" command.)
121 ESC-F Like F, but as soon as a line is found which matches the last
123 search pattern, the terminal bell is rung and forward scrolling
124 stops.
125 g or < or ESC-<
127 Go to line N in the file, default 1 (beginning of file). (Warn‐
128 ing: this may be slow if N is large.)
129 G or > or ESC->
131 Go to line N in the file, default the end of the file. (Warn‐
132 ing: this may be slow if N is large, or if N is not specified
133 and standard input, rather than a file, is being read.)
134 ESC-G Same as G, except if no number N is specified and the input is
136 standard input, goes to the last line which is currently
137 buffered.
138 p or % Go to a position N percent into the file. N should be between 0
140 and 100, and may contain a decimal point.
141 P Go to the line containing byte offset N in the file.
143 { If a left curly bracket appears in the top line displayed on the
145 screen, the { command will go to the matching right curly
146 bracket. The matching right curly bracket is positioned on the
147 bottom line of the screen. If there is more than one left curly
148 bracket on the top line, a number N may be used to specify the
149 N-th bracket on the line.
150 } If a right curly bracket appears in the bottom line displayed on
152 the screen, the } command will go to the matching left curly
153 bracket. The matching left curly bracket is positioned on the
154 top line of the screen. If there is more than one right curly
155 bracket on the top line, a number N may be used to specify the
156 N-th bracket on the line.
157 ( Like {, but applies to parentheses rather than curly brackets.
159 ) Like }, but applies to parentheses rather than curly brackets.
161 [ Like {, but applies to square brackets rather than curly brack‐
163 ets.
164 ] Like }, but applies to square brackets rather than curly brack‐
166 ets.
167 ESC-^F Followed by two characters, acts like {, but uses the two char‐
169 acters as open and close brackets, respectively. For example,
170 "ESC ^F < >" could be used to go forward to the > which matches
171 the < in the top displayed line.
172 ESC-^B Followed by two characters, acts like }, but uses the two char‐
174 acters as open and close brackets, respectively. For example,
175 "ESC ^B < >" could be used to go backward to the < which matches
176 the > in the bottom displayed line.
177 m Followed by any lowercase or uppercase letter, marks the first
179 displayed line with that letter. If the status column is
180 enabled via the -J option, the status column shows the marked
181 line.
182 M Acts like m, except the last displayed line is marked rather
184 than the first displayed line.
185 ' (Single quote.) Followed by any lowercase or uppercase letter,
187 returns to the position which was previously marked with that
188 letter. Followed by another single quote, returns to the posi‐
189 tion at which the last "large" movement command was executed.
190 Followed by a ^ or $, jumps to the beginning or end of the file
191 respectively. Marks are preserved when a new file is examined,
192 so the ' command can be used to switch between input files.
193 ^X^X Same as single quote.
195 ESC-m Followed by any lowercase or uppercase letter, clears the mark
197 identified by that letter.
198 /pattern
200 Search forward in the file for the N-th line containing the pat‐
201 tern. N defaults to 1. The pattern is a regular expression, as
202 recognized by the regular expression library supplied by your
203 system. The search starts at the first line displayed (but see
204 the -a and -j options, which change this).
205 Certain characters are special if entered at the beginning of
207 the pattern; they modify the type of search rather than become
208 part of the pattern:
209 ^N or !
211 Search for lines which do NOT match the pattern.
212 ^E or *
214 Search multiple files. That is, if the search reaches
215 the END of the current file without finding a match, the
216 search continues in the next file in the command line
217 list.
218 ^F or @
220 Begin the search at the first line of the FIRST file in
221 the command line list, regardless of what is currently
222 displayed on the screen or the settings of the -a or -j
223 options.
224 ^K Highlight any text which matches the pattern on the cur‐
226 rent screen, but don't move to the first match (KEEP cur‐
227 rent position).
228 ^R Don't interpret regular expression metacharacters; that
230 is, do a simple textual comparison.
231 ?pattern
233 Search backward in the file for the N-th line containing the
234 pattern. The search starts at the last line displayed (but see
235 the -a and -j options, which change this).
236 Certain characters are special as in the / command:
238 ^N or !
240 Search for lines which do NOT match the pattern.
241 ^E or *
243 Search multiple files. That is, if the search reaches
244 the beginning of the current file without finding a
245 match, the search continues in the previous file in the
246 command line list.
247 ^F or @
249 Begin the search at the last line of the last file in the
250 command line list, regardless of what is currently dis‐
251 played on the screen or the settings of the -a or -j
252 options.
253 ^K As in forward searches.
255 ^R As in forward searches.
257 ESC-/pattern
259 Same as "/*".
260 ESC-?pattern
262 Same as "?*".
263 n Repeat previous search, for N-th line containing the last pat‐
265 tern. If the previous search was modified by ^N, the search is
266 made for the N-th line NOT containing the pattern. If the pre‐
267 vious search was modified by ^E, the search continues in the
268 next (or previous) file if not satisfied in the current file.
269 If the previous search was modified by ^R, the search is done
270 without using regular expressions. There is no effect if the
271 previous search was modified by ^F or ^K.
272 N Repeat previous search, but in the reverse direction.
274 ESC-n Repeat previous search, but crossing file boundaries. The
276 effect is as if the previous search were modified by *.
277 ESC-N Repeat previous search, but in the reverse direction and cross‐
279 ing file boundaries.
280 ESC-u Undo search highlighting. Turn off highlighting of strings
282 matching the current search pattern. If highlighting is already
283 off because of a previous ESC-u command, turn highlighting back
284 on. Any search command will also turn highlighting back on.
285 (Highlighting can also be disabled by toggling the -G option; in
286 that case search commands do not turn highlighting back on.)
287 &pattern
289 Display only lines which match the pattern; lines which do not
290 match the pattern are not displayed. If pattern is empty (if
291 you type & immediately followed by ENTER), any filtering is
292 turned off, and all lines are displayed. While filtering is in
293 effect, an ampersand is displayed at the beginning of the
294 prompt, as a reminder that some lines in the file may be hidden.
295 Certain characters are special as in the / command:
297 ^N or !
299 Display only lines which do NOT match the pattern.
300 ^R Don't interpret regular expression metacharacters; that
302 is, do a simple textual comparison.
303 :e [filename]
305 Examine a new file. If the filename is missing, the "current"
306 file (see the :n and :p commands below) from the list of files
307 in the command line is re-examined. A percent sign (%) in the
308 filename is replaced by the name of the current file. A pound
309 sign (#) is replaced by the name of the previously examined
310 file. However, two consecutive percent signs are simply
311 replaced with a single percent sign. This allows you to enter a
312 filename that contains a percent sign in the name. Similarly,
313 two consecutive pound signs are replaced with a single pound
314 sign. The filename is inserted into the command line list of
315 files so that it can be seen by subsequent :n and :p commands.
316 If the filename consists of several files, they are all inserted
317 into the list of files and the first one is examined. If the
318 filename contains one or more spaces, the entire filename should
319 be enclosed in double quotes (also see the -" option).
320 ^X^V or E
322 Same as :e. Warning: some systems use ^V as a special literal‐
323 ization character. On such systems, you may not be able to use
324 ^V.
325 :n Examine the next file (from the list of files given in the com‐
327 mand line). If a number N is specified, the N-th next file is
328 examined.
329 :p Examine the previous file in the command line list. If a number
331 N is specified, the N-th previous file is examined.
332 :x Examine the first file in the command line list. If a number N
334 is specified, the N-th file in the list is examined.
335 :d Remove the current file from the list of files.
337 t Go to the next tag, if there were more than one matches for the
339 current tag. See the -t option for more details about tags.
340 T Go to the previous tag, if there were more than one matches for
342 the current tag.
343 = or ^G or :f
345 Prints some information about the file being viewed, including
346 its name and the line number and byte offset of the bottom line
347 being displayed. If possible, it also prints the length of the
348 file, the number of lines in the file and the percent of the
349 file above the last displayed line.
350 - Followed by one of the command line option letters (see OPTIONS
352 below), this will change the setting of that option and print a
353 message describing the new setting. If a ^P (CONTROL-P) is
354 entered immediately after the dash, the setting of the option is
355 changed but no message is printed. If the option letter has a
356 numeric value (such as -b or -h), or a string value (such as -P
357 or -t), a new value may be entered after the option letter. If
358 no new value is entered, a message describing the current set‐
359 ting is printed and nothing is changed.
360 -- Like the - command, but takes a long option name (see OPTIONS
362 below) rather than a single option letter. You must press ENTER
363 or RETURN after typing the option name. A ^P immediately after
364 the second dash suppresses printing of a message describing the
365 new setting, as in the - command.
366 -+ Followed by one of the command line option letters this will
368 reset the option to its default setting and print a message
369 describing the new setting. (The "-+X" command does the same
370 thing as "-+X" on the command line.) This does not work for
371 string-valued options.
372 --+ Like the -+ command, but takes a long option name rather than a
374 single option letter.
375 -! Followed by one of the command line option letters, this will
377 reset the option to the "opposite" of its default setting and
378 print a message describing the new setting. This does not work
379 for numeric or string-valued options.
380 --! Like the -! command, but takes a long option name rather than a
382 single option letter.
383 _ (Underscore.) Followed by one of the command line option let‐
385 ters, this will print a message describing the current setting
386 of that option. The setting of the option is not changed.
387 __ (Double underscore.) Like the _ (underscore) command, but takes
389 a long option name rather than a single option letter. You must
390 press ENTER or RETURN after typing the option name.
391 +cmd Causes the specified cmd to be executed each time a new file is
393 examined. For example, +G causes less to initially display each
394 file starting at the end rather than the beginning.
395 V Prints the version number of less being run.
397 q or Q or :q or :Q or ZZ
399 Exits less.
400 The following four commands may or may not be valid, depending on your
402 particular installation.
403 v Invokes an editor to edit the current file being viewed. The
405 editor is taken from the environment variable VISUAL if defined,
406 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei‐
407 ther VISUAL nor EDITOR is defined. See also the discussion of
408 LESSEDIT under the section on PROMPTS below.
409 ! shell-command
411 Invokes a shell to run the shell-command given. A percent sign
412 (%) in the command is replaced by the name of the current file.
413 A pound sign (#) is replaced by the name of the previously exam‐
414 ined file. "!!" repeats the last shell command. "!" with no
415 shell command simply invokes a shell. On Unix systems, the
416 shell is taken from the environment variable SHELL, or defaults
417 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
418 command processor.
419 | <m> shell-command
421 <m> represents any mark letter. Pipes a section of the input
422 file to the given shell command. The section of the file to be
423 piped is between the position marked by the letter and the cur‐
424 rent screen. The entire current screen is included, regardless
425 of whether the marked position is before or after the current
426 screen. <m> may also be ^ or $ to indicate beginning or end of
427 file respectively. If <m> is . or newline, the current screen
428 is piped.
429 s filename
431 Save the input to a file. This only works if the input is a
432 pipe, not an ordinary file.
433
435 Command line options are described below. Most options may be changed
436 while less is running, via the "-" command.
437 Most options may be given in one of two forms: either a dash followed
439 by a single letter, or two dashes followed by a long option name. A
440 long option name may be abbreviated as long as the abbreviation is
441 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
442 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
443 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
444 from --quit-at-eof. Such option names need only have their first let‐
445 ter capitalized; the remainder of the name may be in either case. For
446 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
447 Options are also taken from the environment variable "LESS". For exam‐
449 ple, to avoid typing "less -options ..." each time less is invoked, you
450 might tell csh:
451 setenv LESS "-options"
453 or if you use sh:
455 LESS="-options"; export LESS
457 On MS-DOS, you don't need the quotes, but you should replace any per‐
459 cent signs in the options string by double percent signs.
460 The environment variable is parsed before the command line, so command
462 line options override the LESS environment variable. If an option
463 appears in the LESS variable, it can be reset to its default value on
464 the command line by beginning the command line option with "-+".
465 Some options like -k or -D require a string to follow the option let‐
467 ter. The string for that option is considered to end when a dollar
468 sign ($) is found. For example, you can set two -D options on MS-DOS
469 like this:
470 LESS="Dn9.1$Ds4.1"
472 If the --use-backslash option appears earlier in the options, then a
474 dollar sign or backslash may be included literally in an option string
475 by preceding it with a backslash. If the --use-backslash option is not
476 in effect, then backslashes are not treated specially, and there is no
477 way to include a dollar sign in the option string.
478 -? or --help
480 This option displays a summary of the commands accepted by less
481 (the same as the h command). (Depending on how your shell
482 interprets the question mark, it may be necessary to quote the
483 question mark, thus: "-\?".)
484 -a or --search-skip-screen
486 By default, forward searches start at the top of the displayed
487 screen and backwards searches start at the bottom of the dis‐
488 played screen (except for repeated searches invoked by the n or
489 N commands, which start after or before the "target" line
490 respectively; see the -j option for more about the target line).
491 The -a option causes forward searches to instead start at the
492 bottom of the screen and backward searches to start at the top
493 of the screen, thus skipping all lines displayed on the screen.
494 -A or --SEARCH-SKIP-SCREEN
496 Causes all forward searches (not just non-repeated searches) to
497 start just after the target line, and all backward searches to
498 start just before the target line. Thus, forward searches will
499 skip part of the displayed screen (from the first line up to and
500 including the target line). Similarly backwards searches will
501 skip the displayed screen from the last line up to and including
502 the target line. This was the default behavior in less versions
503 prior to 441.
504 -bn or --buffers=n
506 Specifies the amount of buffer space less will use for each
507 file, in units of kilobytes (1024 bytes). By default 64 K of
508 buffer space is used for each file (unless the file is a pipe;
509 see the -B option). The -b option specifies instead that n
510 kilobytes of buffer space should be used for each file. If n is
511 -1, buffer space is unlimited; that is, the entire file can be
512 read into memory.
513 -B or --auto-buffers
515 By default, when data is read from a pipe, buffers are allocated
516 automatically as needed. If a large amount of data is read from
517 the pipe, this can cause a large amount of memory to be allo‐
518 cated. The -B option disables this automatic allocation of buf‐
519 fers for pipes, so that only 64 K (or the amount of space speci‐
520 fied by the -b option) is used for the pipe. Warning: use of -B
521 can result in erroneous display, since only the most recently
522 viewed part of the piped data is kept in memory; any earlier
523 data is lost.
524 -c or --clear-screen
526 Causes full screen repaints to be painted from the top line
527 down. By default, full screen repaints are done by scrolling
528 from the bottom of the screen.
529 -C or --CLEAR-SCREEN
531 Same as -c, for compatibility with older versions of less.
532 -d or --dumb
534 The -d option suppresses the error message normally displayed if
535 the terminal is dumb; that is, lacks some important capability,
536 such as the ability to clear the screen or scroll backward. The
537 -d option does not otherwise change the behavior of less on a
538 dumb terminal.
539 -Dxcolor or --color=xcolor
541 [MS-DOS only] Sets the color of the text displayed. x is a sin‐
542 gle character which selects the type of text whose color is
543 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
544 color is a pair of numbers separated by a period. The first
545 number selects the foreground color and the second selects the
546 background color of the text. A single number N is the same as
547 N.M, where M is the normal background color. The color may
548 start or end with u to use underline (with the normal color, if
549 by itself), if the system supports it (Windows only). x may
550 also be a to toggle strict ANSI sequence rendering (SGR mode).
551 -e or --quit-at-eof
554 Causes less to automatically exit the second time it reaches
555 end-of-file. By default, the only way to exit less is via the
556 "q" command.
557 -E or --QUIT-AT-EOF
559 Causes less to automatically exit the first time it reaches end-
560 of-file.
561 -f or --force
563 Forces non-regular files to be opened. (A non-regular file is a
564 directory or a device special file.) Also suppresses the warn‐
565 ing message when a binary file is opened. By default, less will
566 refuse to open non-regular files. Note that some operating sys‐
567 tems will not allow directories to be read, even if -f is set.
568 -F or --quit-if-one-screen
570 Causes less to automatically exit if the entire file can be dis‐
571 played on the first screen.
572 -g or --hilite-search
574 Normally, less will highlight ALL strings which match the last
575 search command. The -g option changes this behavior to high‐
576 light only the particular string which was found by the last
577 search command. This can cause less to run somewhat faster than
578 the default.
579 -G or --HILITE-SEARCH
581 The -G option suppresses all highlighting of strings found by
582 search commands.
583 --old-bot
585 Reverts to the old bottom of screen behavior. This can be some‐
586 times desirable if the long lines are not wrapped correctly
587 when reaching the bottom of the terminal, while scrolling
588 forward.
589 -hn or --max-back-scroll=n
591 Specifies a maximum number of lines to scroll backward. If it
592 is necessary to scroll backward more than n lines, the screen is
593 repainted in a forward direction instead. (If the terminal does
594 not have the ability to scroll backward, -h0 is implied.)
595 -i or --ignore-case
597 Causes searches to ignore case; that is, uppercase and lowercase
598 are considered identical. This option is ignored if any upper‐
599 case letters appear in the search pattern; in other words, if a
600 pattern contains uppercase letters, then that search does not
601 ignore case.
602 -I or --IGNORE-CASE
604 Like -i, but searches ignore case even if the pattern contains
605 uppercase letters.
606 -jn or --jump-target=n
608 Specifies a line on the screen where the "target" line is to be
609 positioned. The target line is the line specified by any com‐
610 mand to search for a pattern, jump to a line number, jump to a
611 file percentage or jump to a tag. The screen line may be speci‐
612 fied by a number: the top line on the screen is 1, the next is
613 2, and so on. The number may be negative to specify a line rel‐
614 ative to the bottom of the screen: the bottom line on the screen
615 is -1, the second to the bottom is -2, and so on. Alternately,
616 the screen line may be specified as a fraction of the height of
617 the screen, starting with a decimal point: .5 is in the middle
618 of the screen, .3 is three tenths down from the first line, and
619 so on. If the line is specified as a fraction, the actual line
620 number is recalculated if the terminal window is resized, so
621 that the target line remains at the specified fraction of the
622 screen height. If any form of the -j option is used, repeated
623 forward searches (invoked with "n" or "N") begin at the line
624 immediately after the target line, and repeated backward
625 searches begin at the target line, unless changed by -a or -A.
626 For example, if "-j4" is used, the target line is the fourth
627 line on the screen, so forward searches begin at the fifth line
628 on the screen. However nonrepeated searches (invoked with "/"
629 or "?") always begin at the start or end of the current screen
630 respectively.
631 -J or --status-column
633 Displays a status column at the left edge of the screen. The
634 status column shows the lines that matched the current search,
635 and any lines that are marked (via the m or M command). The
636 status column is also used if the -w or -W option is in effect.
637 -kfilename or --lesskey-file=filename
639 Causes less to open and interpret the named file as a lesskey
640 (1) file. Multiple -k options may be specified. If the LESSKEY
641 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
642 file is found in a standard place (see KEY BINDINGS), it is also
643 used as a lesskey file.
644 -K or --quit-on-intr
646 Causes less to exit immediately (with status 2) when an inter‐
647 rupt character (usually ^C) is typed. Normally, an interrupt
648 character causes less to stop whatever it is doing and return to
649 its command prompt. Note that use of this option makes it
650 impossible to return to the command prompt from the "F" command.
651 -L or --no-lessopen
653 Ignore the LESSOPEN environment variable (see the INPUT PRE‐
654 PROCESSOR section below). This option can be set from within
655 less, but it will apply only to files opened subsequently, not
656 to the file which is currently open.
657 -m or --long-prompt
659 Causes less to prompt verbosely (like more), with the percent
660 into the file. By default, less prompts with a colon.
661 -M or --LONG-PROMPT
663 Causes less to prompt even more verbosely than more.
664 -n or --line-numbers
666 Suppresses line numbers. The default (to use line numbers) may
667 cause less to run more slowly in some cases, especially with a
668 very large input file. Suppressing line numbers with the -n
669 option will avoid this problem. Using line numbers means: the
670 line number will be displayed in the verbose prompt and in the =
671 command, and the v command will pass the current line number to
672 the editor (see also the discussion of LESSEDIT in PROMPTS
673 below).
674 -N or --LINE-NUMBERS
676 Causes a line number to be displayed at the beginning of each
677 line in the display.
678 -ofilename or --log-file=filename
680 Causes less to copy its input to the named file as it is being
681 viewed. This applies only when the input file is a pipe, not an
682 ordinary file. If the file already exists, less will ask for
683 confirmation before overwriting it.
684 -Ofilename or --LOG-FILE=filename
686 The -O option is like -o, but it will overwrite an existing file
687 without asking for confirmation.
688 If no log file has been specified, the -o and -O options can be
690 used from within less to specify a log file. Without a file
691 name, they will simply report the name of the log file. The "s"
692 command is equivalent to specifying -o from within less.
693 -ppattern or --pattern=pattern
695 The -p option on the command line is equivalent to specifying
696 +/pattern; that is, it tells less to start at the first occur‐
697 rence of pattern in the file.
698 -Pprompt or --prompt=prompt
700 Provides a way to tailor the three prompt styles to your own
701 preference. This option would normally be put in the LESS envi‐
702 ronment variable, rather than being typed in with each less com‐
703 mand. Such an option must either be the last option in the LESS
704 variable, or be terminated by a dollar sign.
705 -Ps followed by a string changes the default (short) prompt to
706 that string.
707 -Pm changes the medium (-m) prompt.
708 -PM changes the long (-M) prompt.
709 -Ph changes the prompt for the help screen.
710 -P= changes the message printed by the = command.
711 -Pw changes the message printed while waiting for data (in the
712 F command).
713 All prompt strings consist of a sequence of letters and special
715 escape sequences. See the section on PROMPTS for more details.
716 -q or --quiet or --silent
718 Causes moderately "quiet" operation: the terminal bell is not
719 rung if an attempt is made to scroll past the end of the file or
720 before the beginning of the file. If the terminal has a "visual
721 bell", it is used instead. The bell will be rung on certain
722 other errors, such as typing an invalid character. The default
723 is to ring the terminal bell in all such cases.
724 -Q or --QUIET or --SILENT
726 Causes totally "quiet" operation: the terminal bell is never
727 rung.
728 -r or --raw-control-chars
730 Causes "raw" control characters to be displayed. The default is
731 to display control characters using the caret notation; for
732 example, a control-A (octal 001) is displayed as "^A". Warning:
733 when the -r option is used, less cannot keep track of the actual
734 appearance of the screen (since this depends on how the screen
735 responds to each type of control character). Thus, various dis‐
736 play problems may result, such as long lines being split in the
737 wrong place.
738 -R or --RAW-CONTROL-CHARS
740 Like -r, but only ANSI "color" escape sequences are output in
741 "raw" form. Unlike -r, the screen appearance is maintained cor‐
742 rectly in most cases. ANSI "color" escape sequences are
743 sequences of the form:
744 ESC [ ... m
746 where the "..." is zero or more color specification characters
748 For the purpose of keeping track of screen appearance, ANSI
749 color escape sequences are assumed to not move the cursor. You
750 can make less think that characters other than "m" can end ANSI
751 color escape sequences by setting the environment variable
752 LESSANSIENDCHARS to the list of characters which can end a color
753 escape sequence. And you can make less think that characters
754 other than the standard ones may appear between the ESC and the
755 m by setting the environment variable LESSANSIMIDCHARS to the
756 list of characters which can appear.
757 -s or --squeeze-blank-lines
759 Causes consecutive blank lines to be squeezed into a single
760 blank line. This is useful when viewing nroff output.
761 -S or --chop-long-lines
763 Causes lines longer than the screen width to be chopped (trun‐
764 cated) rather than wrapped. That is, the portion of a long line
765 that does not fit in the screen width is not shown. The default
766 is to wrap long lines; that is, display the remainder on the
767 next line.
768 -ttag or --tag=tag
770 The -t option, followed immediately by a TAG, will edit the file
771 containing that tag. For this to work, tag information must be
772 available; for example, there may be a file in the current
773 directory called "tags", which was previously built by ctags (1)
774 or an equivalent command. If the environment variable LESSGLOB‐
775 ALTAGS is set, it is taken to be the name of a command compati‐
776 ble with global (1), and that command is executed to find the
777 tag. (See http://www.gnu.org/software/global/global.html). The
778 -t option may also be specified from within less (using the -
779 command) as a way of examining a new file. The command ":t" is
780 equivalent to specifying -t from within less.
781 -Ttagsfile or --tag-file=tagsfile
783 Specifies a tags file to be used instead of "tags".
784 -u or --underline-special
786 Causes backspaces and carriage returns to be treated as print‐
787 able characters; that is, they are sent to the terminal when
788 they appear in the input.
789 -U or --UNDERLINE-SPECIAL
791 Causes backspaces, tabs, carriage returns and "formatting char‐
792 acters" (as defined by Unicode) to be treated as control charac‐
793 ters; that is, they are handled as specified by the -r option.
794 By default, if neither -u nor -U is given, backspaces which
796 appear adjacent to an underscore character are treated spe‐
797 cially: the underlined text is displayed using the terminal's
798 hardware underlining capability. Also, backspaces which appear
799 between two identical characters are treated specially: the
800 overstruck text is printed using the terminal's hardware bold‐
801 face capability. Other backspaces are deleted, along with the
802 preceding character. Carriage returns immediately followed by a
803 newline are deleted. Other carriage returns are handled as
804 specified by the -r option. Text which is overstruck or under‐
805 lined can be searched for if neither -u nor -U is in effect.
806 -V or --version
808 Displays the version number of less.
809 -w or --hilite-unread
811 Temporarily highlights the first "new" line after a forward
812 movement of a full page. The first "new" line is the line imme‐
813 diately following the line previously at the bottom of the
814 screen. Also highlights the target line after a g or p command.
815 The highlight is removed at the next command which causes move‐
816 ment. The entire line is highlighted, unless the -J option is
817 in effect, in which case only the status column is highlighted.
818 -W or --HILITE-UNREAD
820 Like -w, but temporarily highlights the first new line after any
821 forward movement command larger than one line.
822 -xn,... or --tabs=n,...
824 Sets tab stops. If only one n is specified, tab stops are set
825 at multiples of n. If multiple values separated by commas are
826 specified, tab stops are set at those positions, and then con‐
827 tinue with the same spacing as the last two. For example,
828 -x9,17 will set tabs at positions 9, 17, 25, 33, etc. The
829 default for n is 8.
830 -X or --no-init
832 Disables sending the termcap initialization and deinitialization
833 strings to the terminal. This is sometimes desirable if the
834 deinitialization string does something unnecessary, like clear‐
835 ing the screen.
836 -yn or --max-forw-scroll=n
838 Specifies a maximum number of lines to scroll forward. If it is
839 necessary to scroll forward more than n lines, the screen is
840 repainted instead. The -c or -C option may be used to repaint
841 from the top of the screen if desired. By default, any forward
842 movement causes scrolling.
843 -zn or --window=n or -n
845 Changes the default scrolling window size to n lines. The
846 default is one screenful. The z and w commands can also be used
847 to change the window size. The "z" may be omitted for compati‐
848 bility with some versions of more. If the number n is negative,
849 it indicates n lines less than the current screen size. For
850 example, if the screen is 24 lines, -z-4 sets the scrolling win‐
851 dow to 20 lines. If the screen is resized to 40 lines, the
852 scrolling window automatically changes to 36 lines.
853 -"cc or --quotes=cc
855 Changes the filename quoting character. This may be necessary
856 if you are trying to name a file which contains both spaces and
857 quote characters. Followed by a single character, this changes
858 the quote character to that character. Filenames containing a
859 space should then be surrounded by that character rather than by
860 double quotes. Followed by two characters, changes the open
861 quote to the first character, and the close quote to the second
862 character. Filenames containing a space should then be preceded
863 by the open quote character and followed by the close quote
864 character. Note that even after the quote characters are
865 changed, this option remains -" (a dash followed by a double
866 quote).
867 -~ or --tilde
869 Normally lines after end of file are displayed as a single tilde
870 (~). This option causes lines after end of file to be displayed
871 as blank lines.
872 -# or --shift
874 Specifies the default number of positions to scroll horizontally
875 in the RIGHTARROW and LEFTARROW commands. If the number speci‐
876 fied is zero, it sets the default number of positions to one
877 half of the screen width. Alternately, the number may be speci‐
878 fied as a fraction of the width of the screen, starting with a
879 decimal point: .5 is half of the screen width, .3 is three
880 tenths of the screen width, and so on. If the number is speci‐
881 fied as a fraction, the actual number of scroll positions is
882 recalculated if the terminal window is resized, so that the
883 actual scroll remains at the specified fraction of the screen
884 width.
885 --follow-name
887 Normally, if the input file is renamed while an F command is
888 executing, less will continue to display the contents of the
889 original file despite its name change. If --follow-name is
890 specified, during an F command less will periodically attempt to
891 reopen the file by name. If the reopen succeeds and the file is
892 a different file from the original (which means that a new file
893 has been created with the same name as the original (now
894 renamed) file), less will display the contents of that new file.
895 --mouse
897 Enables mouse input: scrolling the mouse wheel down moves for‐
898 ward in the file, scrolling the mouse wheel up moves backwards
899 in the file, and clicking the mouse sets the "#" mark to the
900 line where the mouse is clicked. The number of lines to scroll
901 when the wheel is moved can be set by the --wheel-lines option.
902 Mouse input works only on terminals which support X11 mouse
903 reporting, and on the Windows version of less.
904 --MOUSE
906 Like --mouse, except the direction scrolled on mouse wheel move‐
907 ment is reversed.
908 --no-keypad
910 Disables sending the keypad initialization and deinitialization
911 strings to the terminal. This is sometimes useful if the keypad
912 strings make the numeric keypad behave in an undesirable manner.
913 --no-histdups
915 This option changes the behavior so that if a search string or
916 file name is typed in, and the same string is already in the
917 history list, the existing copy is removed from the history list
918 before the new one is added. Thus, a given string will appear
919 only once in the history list. Normally, a string may appear
920 multiple times.
921 --rscroll
923 This option changes the character used to mark truncated lines.
924 It may begin with a two-character attribute indicator like LESS‐
925 BINFMT does. If there is no attribute indicator, standout is
926 used. If set to "-", truncated lines are not marked.
927 --save-marks
929 Save marks in the history file, so marks are retained across
930 different invocations of less.
931 --use-backslash
933 This option changes the interpretations of options which follow
934 this one. After the --use-backslash option, any backslash in an
935 option string is removed and the following character is taken
936 literally. This allows a dollar sign to be included in option
937 strings.
938 --wheel-lines=n
940 Set the number of lines to scroll when the mouse wheel is
941 scrolled and the --mouse or --MOUSE option is in effect. The
942 default is 1 line.
943 -- A command line argument of "--" marks the end of option argu‐
945 ments. Any arguments following this are interpreted as file‐
946 names. This can be useful when viewing a file whose name begins
947 with a "-" or "+".
948 + If a command line option begins with +, the remainder of that
950 option is taken to be an initial command to less. For example,
951 +G tells less to start at the end of the file rather than the
952 beginning, and +/xyz tells it to start at the first occurrence
953 of "xyz" in the file. As a special case, +<number> acts like
954 +<number>g; that is, it starts the display at the specified line
955 number (however, see the caveat under the "g" command above).
956 If the option starts with ++, the initial command applies to
957 every file being viewed, not just the first one. The + command
958 described previously may also be used to set (or change) an ini‐
959 tial command for every file.
960
963 When entering command line at the bottom of the screen (for example, a
964 filename for the :e command, or the pattern for a search command), cer‐
965 tain keys can be used to manipulate the command line. Most commands
966 have an alternate form in [ brackets ] which can be used if a key does
967 not exist on a particular keyboard. (Note that the forms beginning
968 with ESC do not work in some MS-DOS and Windows systems because ESC is
969 the line erase character.) Any of these special keys may be entered
970 literally by preceding it with the "literal" character, either ^V or
971 ^A. A backslash itself may also be entered literally by entering two
972 backslashes.
973 LEFTARROW [ ESC-h ]
975 Move the cursor one space to the left.
976 RIGHTARROW [ ESC-l ]
978 Move the cursor one space to the right.
979 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
981 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur‐
982 sor one word to the left.
983 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
985 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur‐
986 sor one word to the right.
987 HOME [ ESC-0 ]
989 Move the cursor to the beginning of the line.
990 END [ ESC-$ ]
992 Move the cursor to the end of the line.
993 BACKSPACE
995 Delete the character to the left of the cursor, or cancel the
996 command if the command line is empty.
997 DELETE or [ ESC-x ]
999 Delete the character under the cursor.
1000 ^BACKSPACE [ ESC-BACKSPACE ]
1002 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
1003 word to the left of the cursor.
1004 ^DELETE [ ESC-X or ESC-DELETE ]
1006 (That is, CONTROL and DELETE simultaneously.) Delete the word
1007 under the cursor.
1008 UPARROW [ ESC-k ]
1010 Retrieve the previous command line. If you first enter some
1011 text and then press UPARROW, it will retrieve the previous com‐
1012 mand which begins with that text.
1013 DOWNARROW [ ESC-j ]
1015 Retrieve the next command line. If you first enter some text
1016 and then press DOWNARROW, it will retrieve the next command
1017 which begins with that text.
1018 TAB Complete the partial filename to the left of the cursor. If it
1020 matches more than one filename, the first match is entered into
1021 the command line. Repeated TABs will cycle thru the other
1022 matching filenames. If the completed filename is a directory, a
1023 "/" is appended to the filename. (On MS-DOS systems, a "\" is
1024 appended.) The environment variable LESSSEPARATOR can be used
1025 to specify a different character to append to a directory name.
1026 BACKTAB [ ESC-TAB ]
1028 Like, TAB, but cycles in the reverse direction thru the matching
1029 filenames.
1030 ^L Complete the partial filename to the left of the cursor. If it
1032 matches more than one filename, all matches are entered into the
1033 command line (if they fit).
1034 ^U (Unix and OS/2) or ESC (MS-DOS)
1036 Delete the entire command line, or cancel the command if the
1037 command line is empty. If you have changed your line-kill char‐
1038 acter in Unix to something other than ^U, that character is used
1039 instead of ^U.
1040 ^G Delete the entire command line and return to the main prompt.
1042
1045 You may define your own less commands by using the program lesskey (1)
1046 to create a lesskey file. This file specifies a set of command keys
1047 and an action associated with each key. You may also use lesskey to
1048 change the line-editing keys (see LINE EDITING), and to set environment
1049 variables. If the environment variable LESSKEY is set, less uses that
1050 as the name of the lesskey file. Otherwise, less looks in a standard
1051 place for the lesskey file: On Unix systems, less looks for a lesskey
1052 file called "$HOME/.less". On MS-DOS and Windows systems, less looks
1053 for a lesskey file called "$HOME/_less", and if it is not found there,
1054 then looks for a lesskey file called "_less" in any directory specified
1055 in the PATH environment variable. On OS/2 systems, less looks for a
1056 lesskey file called "$HOME/less.ini", and if it is not found, then
1057 looks for a lesskey file called "less.ini" in any directory specified
1058 in the INIT environment variable, and if it not found there, then looks
1059 for a lesskey file called "less.ini" in any directory specified in the
1060 PATH environment variable. See the lesskey manual page for more
1061 details.
1062 A system-wide lesskey file may also be set up to provide key bindings.
1064 If a key is defined in both a local lesskey file and in the system-wide
1065 file, key bindings in the local file take precedence over those in the
1066 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
1067 less uses that as the name of the system-wide lesskey file. Otherwise,
1068 less looks in a standard place for the system-wide lesskey file: On
1069 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1070 (However, if less was built with a different sysconf directory than
1071 /usr/local/etc, that directory is where the sysless file is found.) On
1072 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys‐
1073 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
1074
1077 You may define an "input preprocessor" for less. Before less opens a
1078 file, it first gives your input preprocessor a chance to modify the way
1079 the contents of the file are displayed. An input preprocessor is sim‐
1080 ply an executable program (or shell script), which writes the contents
1081 of the file to a different file, called the replacement file. The con‐
1082 tents of the replacement file are then displayed in place of the con‐
1083 tents of the original file. However, it will appear to the user as if
1084 the original file is opened; that is, less will display the original
1085 filename as the name of the current file.
1086 An input preprocessor receives one command line argument, the original
1088 filename, as entered by the user. It should create the replacement
1089 file, and when finished, print the name of the replacement file to its
1090 standard output. If the input preprocessor does not output a replace‐
1091 ment filename, less uses the original file, as normal. The input pre‐
1092 processor is not called when viewing standard input. To set up an
1093 input preprocessor, set the LESSOPEN environment variable to a command
1094 line which will invoke your input preprocessor. This command line
1095 should include one occurrence of the string "%s", which will be
1096 replaced by the filename when the input preprocessor command is
1097 invoked.
1098 When less closes a file opened in such a way, it will call another pro‐
1100 gram, called the input postprocessor, which may perform any desired
1101 clean-up action (such as deleting the replacement file created by
1102 LESSOPEN). This program receives two command line arguments, the orig‐
1103 inal filename as entered by the user, and the name of the replacement
1104 file. To set up an input postprocessor, set the LESSCLOSE environment
1105 variable to a command line which will invoke your input postprocessor.
1106 It may include two occurrences of the string "%s"; the first is
1107 replaced with the original name of the file and the second with the
1108 name of the replacement file, which was output by LESSOPEN.
1109 For example, on many Unix systems, these two scripts will allow you to
1111 keep files in compressed format, but still let less view them directly:
1112 lessopen.sh:
1114 #! /bin/sh
1115 case "$1" in
1116 *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1117 if [ -s /tmp/less.$$ ]; then
1118 echo /tmp/less.$$
1119 else
1120 rm -f /tmp/less.$$
1121 fi
1122 ;;
1123 esac
1124 lessclose.sh:
1126 #! /bin/sh
1127 rm $2
1128 To use these scripts, put them both where they can be executed and set
1130 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1131 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1132 types of compressed files, and so on.
1133 It is also possible to set up an input preprocessor to pipe the file
1135 data directly to less, rather than putting the data into a replacement
1136 file. This avoids the need to decompress the entire file before start‐
1137 ing to view it. An input preprocessor that works this way is called an
1138 input pipe. An input pipe, instead of writing the name of a replace‐
1139 ment file on its standard output, writes the entire contents of the
1140 replacement file on its standard output. If the input pipe does not
1141 write any characters on its standard output, then there is no replace‐
1142 ment file and less uses the original file, as normal. To use an input
1143 pipe, make the first character in the LESSOPEN environment variable a
1144 vertical bar (|) to signify that the input preprocessor is an input
1145 pipe. As with non-pipe input preprocessors, the command string must
1146 contain one occurrence of %s, which is replaced with the filename of
1147 the input file.
1148 For example, on many Unix systems, this script will work like the pre‐
1150 vious example scripts:
1151 lesspipe.sh:
1153 #! /bin/sh
1154 case "$1" in
1155 *.Z) uncompress -c $1 2>/dev/null
1156 ;;
1157 *) exit 1
1158 ;;
1159 esac
1160 exit $?
1161 To use this script, put it where it can be executed and set
1163 LESSOPEN="|lesspipe.sh %s".
1164 Note that a preprocessor cannot output an empty file, since that is
1166 interpreted as meaning there is no replacement, and the original file
1167 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1168 exit status of the script becomes meaningful. If the exit status is
1169 zero, the output is considered to be replacement text, even if it is
1170 empty. If the exit status is nonzero, any output is ignored and the
1171 original file is used. For compatibility with previous versions of
1172 less, if LESSOPEN starts with only one vertical bar, the exit status of
1173 the preprocessor is ignored.
1174 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1176 it is usually not necessary since there is no replacement file to clean
1177 up. In this case, the replacement file name passed to the LESSCLOSE
1178 postprocessor is "-".
1179 For compatibility with previous versions of less, the input preproces‐
1181 sor or pipe is not used if less is viewing standard input. However, if
1182 the first character of LESSOPEN is a dash (-), the input preprocessor
1183 is used on standard input as well as other files. In this case, the
1184 dash is not considered to be part of the preprocessor command. If
1185 standard input is being viewed, the input preprocessor is passed a file
1186 name consisting of a single dash. Similarly, if the first two charac‐
1187 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1188 and a dash (||-), the input pipe is used on standard input as well as
1189 other files. Again, in this case the dash is not considered to be part
1190 of the input pipe command.
1191 There are used following files to set up default preprocessor:
1193 /etc/profile.d/less.sh
1194 /etc/profile.d/less.csh
1195 These files set up /usr/bin/lesspipe.sh as a default filter. An user
1196 defined filter can be specified in ~/.lessfilter. This file should have
1197 an execute bit set and accept only one parameter, which represents a
1198 filename. If the user defined filter process the file, zero should be
1199 returned. Otherwise ~/.lessfilter tries to handle the file.
1200
1203 There are three types of characters in the input file:
1204 normal characters
1206 can be displayed directly to the screen.
1207 control characters
1209 should not be displayed directly, but are expected to be found
1210 in ordinary text files (such as backspace and tab).
1211 binary characters
1213 should not be displayed directly and are not expected to be
1214 found in text files.
1215 A "character set" is simply a description of which characters are to be
1217 considered normal, control, and binary. The LESSCHARSET environment
1218 variable may be used to select a character set. Possible values for
1219 LESSCHARSET are:
1220 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1222 with values between 32 and 126 are normal, and all others are
1223 binary.
1224 iso8859
1226 Selects an ISO 8859 character set. This is the same as ASCII,
1227 except characters between 160 and 255 are treated as normal
1228 characters.
1229 latin1 Same as iso8859.
1231 latin9 Same as iso8859.
1233 dos Selects a character set appropriate for MS-DOS.
1235 ebcdic Selects an EBCDIC character set.
1237 IBM-1047
1239 Selects an EBCDIC character set used by OS/390 Unix Services.
1240 This is the EBCDIC analogue of latin1. You get similar results
1241 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1242 environment.
1243 koi8-r Selects a Russian character set.
1245 next Selects a character set appropriate for NeXT computers.
1247 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1249 UTF-8 is special in that it supports multi-byte characters in
1250 the input file. It is the only character set that supports
1251 multi-byte characters.
1252 windows
1254 Selects a character set appropriate for Microsoft Windows (cp
1255 1251).
1256 In rare cases, it may be desired to tailor less to use a character set
1258 other than the ones definable by LESSCHARSET. In this case, the envi‐
1259 ronment variable LESSCHARDEF can be used to define a character set. It
1260 should be set to a string where each character in the string represents
1261 one character in the character set. The character "." is used for a
1262 normal character, "c" for control, and "b" for binary. A decimal num‐
1263 ber may be used for repetition. For example, "bccc4b." would mean
1264 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1265 binary, and 8 is normal. All characters after the last are taken to be
1266 the same as the last, so characters 9 through 255 would be normal.
1267 (This is an example, and does not necessarily represent any real char‐
1268 acter set.)
1269 This table shows the value of LESSCHARDEF which is equivalent to each
1271 of the possible values for LESSCHARSET:
1272 ascii 8bcccbcc18b95.b
1274 dos 8bcccbcc12bc5b95.b.
1275 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1276 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1277 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1278 191.b
1279 iso8859 8bcccbcc18b95.33b.
1280 koi8-r 8bcccbcc18b95.b128.
1281 latin1 8bcccbcc18b95.33b.
1282 next 8bcccbcc18b95.bb125.bb
1283 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1285 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1286 LANG environment variables, then the default character set is utf-8.
1287 If that string is not found, but your system supports the setlocale
1289 interface, less will use setlocale to determine the character set.
1290 setlocale is controlled by setting the LANG or LC_CTYPE environment
1291 variables.
1292 Finally, if the setlocale interface is also not available, the default
1294 character set is latin1.
1295 Control and binary characters are displayed in standout (reverse
1297 video). Each such character is displayed in caret notation if possible
1298 (e.g. ^A for control-A). Caret notation is used only if inverting the
1299 0100 bit results in a normal printable character. Otherwise, the char‐
1300 acter is displayed as a hex number in angle brackets. This format can
1301 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1302 may begin with a "*" and one character to select the display attribute:
1303 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1304 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1305 attribute is assumed. The remainder of LESSBINFMT is a string which
1306 may include one printf-style escape sequence (a % followed by x, X, o,
1307 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1308 are displayed in underlined hexadecimal surrounded by brackets. The
1309 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1310 result of expanding the character via LESSBINFMT must be less than 31
1311 characters.
1312 When the character set is utf-8, the LESSUTFBINFMT environment variable
1314 acts similarly to LESSBINFMT but it applies to Unicode code points that
1315 were successfully decoded but are unsuitable for display (e.g., unas‐
1316 signed code points). Its default value is "<U+%04lX>". Note that
1317 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1318 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1319 LESSBINFMT so its setting, if any, will have priority. Problematic
1320 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1321 complete but non-shortest form sequence, illegal octets, and stray
1322 trailing octets) are displayed individually using LESSBINFMT so as to
1323 facilitate diagnostic of how the UTF-8 file is ill-formed.
1324
1327 The -P option allows you to tailor the prompt to your preference. The
1328 string given to the -P option replaces the specified prompt string.
1329 Certain characters in the string are interpreted specially. The prompt
1330 mechanism is rather complicated to provide flexibility, but the ordi‐
1331 nary user need not understand the details of constructing personalized
1332 prompt strings.
1333 A percent sign followed by a single character is expanded according to
1335 what the following character is:
1336 %bX Replaced by the byte offset into the current input file. The b
1338 is followed by a single character (shown as X above) which spec‐
1339 ifies the line whose byte offset is to be used. If the charac‐
1340 ter is a "t", the byte offset of the top line in the display is
1341 used, an "m" means use the middle line, a "b" means use the bot‐
1342 tom line, a "B" means use the line just after the bottom line,
1343 and a "j" means use the "target" line, as specified by the -j
1344 option.
1345 %B Replaced by the size of the current input file.
1347 %c Replaced by the column number of the text appearing in the first
1349 column of the screen.
1350 %dX Replaced by the page number of a line in the input file. The
1352 line to be used is determined by the X, as with the %b option.
1353 %D Replaced by the number of pages in the input file, or equiva‐
1355 lently, the page number of the last line in the input file.
1356 %E Replaced by the name of the editor (from the VISUAL environment
1358 variable, or the EDITOR environment variable if VISUAL is not
1359 defined). See the discussion of the LESSEDIT feature below.
1360 %f Replaced by the name of the current input file.
1362 %F Replaced by the last component of the name of the current input
1364 file.
1365 %g Replaced by the shell-escaped name of the current input file.
1367 This is useful when the expanded string will be used in a shell
1368 command, such as in LESSEDIT.
1369 %i Replaced by the index of the current file in the list of input
1371 files.
1372 %lX Replaced by the line number of a line in the input file. The
1374 line to be used is determined by the X, as with the %b option.
1375 %L Replaced by the line number of the last line in the input file.
1377 %m Replaced by the total number of input files.
1379 %pX Replaced by the percent into the current input file, based on
1381 byte offsets. The line used is determined by the X as with the
1382 %b option.
1383 %PX Replaced by the percent into the current input file, based on
1385 line numbers. The line used is determined by the X as with the
1386 %b option.
1387 %s Same as %B.
1389 %t Causes any trailing spaces to be removed. Usually used at the
1391 end of the string, but may appear anywhere.
1392 %T Normally expands to the word "file". However if viewing files
1394 via a tags list using the -t option, it expands to the word
1395 "tag".
1396 %x Replaced by the name of the next input file in the list.
1398 If any item is unknown (for example, the file size if input is a pipe),
1400 a question mark is printed instead.
1401 The format of the prompt string can be changed depending on certain
1403 conditions. A question mark followed by a single character acts like
1404 an "IF": depending on the following character, a condition is evalu‐
1405 ated. If the condition is true, any characters following the question
1406 mark and condition character, up to a period, are included in the
1407 prompt. If the condition is false, such characters are not included.
1408 A colon appearing between the question mark and the period can be used
1409 to establish an "ELSE": any characters between the colon and the period
1410 are included in the string if and only if the IF condition is false.
1411 Condition characters (which follow a question mark) may be:
1412 ?a True if any characters have been included in the prompt so far.
1414 ?bX True if the byte offset of the specified line is known.
1416 ?B True if the size of current input file is known.
1418 ?c True if the text is horizontally shifted (%c is not zero).
1420 ?dX True if the page number of the specified line is known.
1422 ?e True if at end-of-file.
1424 ?f True if there is an input filename (that is, if input is not a
1426 pipe).
1427 ?lX True if the line number of the specified line is known.
1429 ?L True if the line number of the last line in the file is known.
1431 ?m True if there is more than one input file.
1433 ?n True if this is the first prompt in a new input file.
1435 ?pX True if the percent into the current input file, based on byte
1437 offsets, of the specified line is known.
1438 ?PX True if the percent into the current input file, based on line
1440 numbers, of the specified line is known.
1441 ?s Same as "?B".
1443 ?x True if there is a next input file (that is, if the current
1445 input file is not the last one).
1446 Any characters other than the special ones (question mark, colon,
1448 period, percent, and backslash) become literally part of the prompt.
1449 Any of the special characters may be included in the prompt literally
1450 by preceding it with a backslash.
1451 Some examples:
1453 ?f%f:Standard input.
1455 This prompt prints the filename, if known; otherwise the string "Stan‐
1457 dard input".
1458 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1460 This prompt would print the filename, if known. The filename is fol‐
1462 lowed by the line number, if known, otherwise the percent if known,
1463 otherwise the byte offset if known. Otherwise, a dash is printed.
1464 Notice how each question mark has a matching period, and how the %
1465 after the %pt is included literally by escaping it with a backslash.
1466 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1468 This prints the filename if this is the first prompt in a file, fol‐
1470 lowed by the "file N of N" message if there is more than one input
1471 file. Then, if we are at end-of-file, the string "(END)" is printed
1472 followed by the name of the next file, if there is one. Finally, any
1473 trailing spaces are truncated. This is the default prompt. For refer‐
1474 ence, here are the defaults for the other two prompts (-m and -M
1475 respectively). Each is broken into two lines here for readability
1476 only.
1477 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1479 ?pB%pB\%:byte %bB?s/%s...%t
1480 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1482 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1483 And here is the default message produced by the = command:
1485 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1487 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1488 The prompt expansion features are also used for another purpose: if an
1490 environment variable LESSEDIT is defined, it is used as the command to
1491 be executed when the v command is invoked. The LESSEDIT string is
1492 expanded in the same way as the prompt strings. The default value for
1493 LESSEDIT is:
1494 %E ?lm+%lm. %g
1496 Note that this expands to the editor name, followed by a + and the line
1498 number, followed by the shell-escaped file name. If your editor does
1499 not accept the "+linenumber" syntax, or has other differences in invo‐
1500 cation syntax, the LESSEDIT variable can be changed to modify this
1501 default.
1502
1505 When the environment variable LESSSECURE is set to 1, less runs in a
1506 "secure" mode. This means these features are disabled:
1507 ! the shell command
1509 | the pipe command
1511 :e the examine command.
1513 v the editing command
1515 s -o log files
1517 -k use of lesskey files
1519 -t use of tags files
1521 metacharacters in filenames, such as *
1523 filename completion (TAB, ^L)
1525 Less can also be compiled to be permanently in "secure" mode.
1527
1530 If the environment variable LESS_IS_MORE is set to 1, or if the program
1531 is invoked via a file link named "more", less behaves (mostly) in con‐
1532 formance with the POSIX "more" command specification. In this mode,
1533 less behaves differently in these ways:
1534 The -e option works differently. If the -e option is not set, less
1536 behaves as if the -e option were set. If the -e option is set, less
1537 behaves as if the -E option were set.
1538 The -m option works differently. If the -m option is not set, the
1540 medium prompt is used, and it is prefixed with the string "--More--".
1541 If the -m option is set, the short prompt is used.
1542 The -n option acts like the -z option. The normal behavior of the -n
1544 option is unavailable in this mode.
1545 The parameter to the -p option is taken to be a less command rather
1547 than a search pattern.
1548 The LESS environment variable is ignored, and the MORE environment
1550 variable is used in its place.
1551
1554 Environment variables may be specified either in the system environment
1555 as usual, or in a lesskey (1) file. If environment variables are
1556 defined in more than one place, variables defined in a local lesskey
1557 file take precedence over variables defined in the system environment,
1558 which take precedence over variables defined in the system-wide lesskey
1559 file.
1560 COLUMNS
1562 Sets the number of columns on the screen. Takes precedence over
1563 the number of columns specified by the TERM variable. (But if
1564 you have a windowing system which supports TIOCGWINSZ or
1565 WIOCGETD, the window system's idea of the screen size takes
1566 precedence over the LINES and COLUMNS environment variables.)
1567 EDITOR The name of the editor (used for the v command).
1569 HOME Name of the user's home directory (used to find a lesskey file
1571 on Unix and OS/2 systems).
1572 HOMEDRIVE, HOMEPATH
1574 Concatenation of the HOMEDRIVE and HOMEPATH environment vari‐
1575 ables is the name of the user's home directory if the HOME vari‐
1576 able is not set (only in the Windows version).
1577 INIT Name of the user's init directory (used to find a lesskey file
1579 on OS/2 systems).
1580 LANG Language for determining the character set.
1582 LC_CTYPE
1584 Language for determining the character set.
1585 LESS Options which are passed to less automatically.
1587 LESSANSIENDCHARS
1589 Characters which may end an ANSI color escape sequence (default
1590 "m").
1591 LESSANSIMIDCHARS
1593 Characters which may appear between the ESC character and the
1594 end character in an ANSI color escape sequence (default
1595 "0123456789:;[?!"'#%()*+ ".
1596 LESSBINFMT
1598 Format for displaying non-printable, non-control characters.
1599 LESSCHARDEF
1601 Defines a character set.
1602 LESSCHARSET
1604 Selects a predefined character set.
1605 LESSCLOSE
1607 Command line to invoke the (optional) input-postprocessor.
1608 LESSECHO
1610 Name of the lessecho program (default "lessecho"). The lessecho
1611 program is needed to expand metacharacters, such as * and ?, in
1612 filenames on Unix systems.
1613 LESSEDIT
1615 Editor prototype string (used for the v command). See discus‐
1616 sion under PROMPTS.
1617 LESSGLOBALTAGS
1619 Name of the command used by the -t option to find global tags.
1620 Normally should be set to "global" if your system has the global
1621 (1) command. If not set, global tags are not used.
1622 LESSHISTFILE
1624 Name of the history file used to remember search commands and
1625 shell commands between invocations of less. If set to "-" or
1626 "/dev/null", a history file is not used. The default is
1627 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1628 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1629 on OS/2 systems.
1630 LESSHISTSIZE
1632 The maximum number of commands to save in the history file. The
1633 default is 100.
1634 LESSKEY
1636 Name of the default lesskey(1) file.
1637 LESSKEY_SYSTEM
1639 Name of the default system-wide lesskey(1) file.
1640 LESSMETACHARS
1642 List of characters which are considered "metacharacters" by the
1643 shell.
1644 LESSMETAESCAPE
1646 Prefix which less will add before each metacharacter in a com‐
1647 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1648 commands containing metacharacters will not be passed to the
1649 shell.
1650 LESSOPEN
1652 Command line to invoke the (optional) input-preprocessor.
1653 LESSSECURE
1655 Runs less in "secure" mode. See discussion under SECURITY.
1656 LESSSEPARATOR
1658 String to be appended to a directory name in filename comple‐
1659 tion.
1660 LESSUTFBINFMT
1662 Format for displaying non-printable Unicode code points.
1663 LESS_IS_MORE
1665 Emulate the more (1) command.
1666 LINES Sets the number of lines on the screen. Takes precedence over
1668 the number of lines specified by the TERM variable. (But if you
1669 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1670 the window system's idea of the screen size takes precedence
1671 over the LINES and COLUMNS environment variables.)
1672 MORE Options which are passed to less automatically when running in
1674 more compatible mode.
1675 PATH User's search path (used to find a lesskey file on MS-DOS and
1677 OS/2 systems).
1678 SHELL The shell used to execute the ! command, as well as to expand
1680 filenames.
1681 TERM The type of terminal on which less is being run.
1683 VISUAL The name of the editor (used for the v command).
1685
1688 lesskey(1)
1689
1692 Copyright (C) 1984-2019 Mark Nudelman
1693 less is part of the GNU project and is free software. You can redis‐
1695 tribute it and/or modify it under the terms of either (1) the GNU Gen‐
1696 eral Public License as published by the Free Software Foundation; or
1697 (2) the Less License. See the file README in the less distribution for
1698 more details regarding redistribution. You should have received a copy
1699 of the GNU General Public License along with the source for less; see
1700 the file COPYING. If not, write to the Free Software Foundation, 59
1701 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1702 have received a copy of the Less License; see the file LICENSE.
1703 less is distributed in the hope that it will be useful, but WITHOUT ANY
1705 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT‐
1706 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1707 more details.
1708
1711 Mark Nudelman
1712 Send bug reports or comments to <bug-less@gnu.org>
1713 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1714 of known bugs in less.
1715 For more information, see the less homepage at
1716 http://www.greenwoodsoftware.com/less.
1717 Version 550: 16 Feb 2019 LESS(1)