1 LESS(1) General Commands Manual LESS(1)
6 less - opposite of more
12 \e[1mless --version
\e[0m
13 \e[1mless [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
\e[0m
14 \e[1m[-b
\e[4m
\e[22mspace
\e[24m
\e[1m] [-h
\e[4m
\e[22mlines
\e[24m
\e[1m] [-j
\e[4m
\e[22mline
\e[24m
\e[1m] [-k
\e[4m
\e[22mkeyfile
\e[24m
\e[1m]
\e[0m
15 \e[1m[-{oO}
\e[4m
\e[22mlogfile
\e[24m
\e[1m] [-p
\e[4m
\e[22mpattern
\e[24m
\e[1m] [-P
\e[4m
\e[22mprompt
\e[24m
\e[1m] [-t
\e[4m
\e[22mtag
\e[24m
\e[1m]
\e[0m
16 \e[1m[-T
\e[4m
\e[22mtagsfile
\e[24m
\e[1m] [-x
\e[4m
\e[22mtab
\e[24m
\e[1m,...] [-y
\e[4m
\e[22mlines
\e[24m
\e[1m] [-[z]
\e[4m
\e[22mlines
\e[24m
\e[1m]
\e[0m
17 \e[1m[-#
\e[4m
\e[22mshift
\e[24m
\e[1m] [+[+]
\e[4m
\e[22mcmd
\e[24m
\e[1m] [--] [
\e[4m
\e[22mfilename
\e[24m
\e[1m]...
\e[0m
18 (See the OPTIONS section for alternate option syntax with long option
23 \e[4mLess
\e[24m is a program similar to
\e[4mmore
\e[24m (1), but which allows backward move-
24 ment in the file as well as forward movement. Also,
\e[4mless
\e[24m does not have
25 to read the entire input file before starting, so with large input
26 files it starts up faster than text editors like
\e[4mvi
\e[24m (1).
\e[4mLess
\e[24m uses
27 termcap (or terminfo on some systems), so it can run on a variety of
28 terminals. There is even limited support for hardcopy terminals. (On
29 a hardcopy terminal, lines which should be printed at the top of the
30 screen are prefixed with a caret.)
32 Commands are based on both
\e[4mmore
\e[24m and
\e[4mvi.
\e[24m Commands may be preceded by a
33 decimal number, called N in the descriptions below. The number is used
34 by some commands, as indicated.
38 In the following descriptions, ^X means control-X. ESC stands for the
39 ESCAPE key; for example ESC-v means the two character sequence
42 h or H Help: display a summary of these commands. If you forget all
43 the other commands, remember this one.
45 SPACE or ^V or f or ^F
46 Scroll forward N lines, default one window (see option -z
47 below). If N is more than the screen size, only the final
48 screenful is displayed. Warning: some systems use ^V as a spe-
49 cial literalization character.
51 z Like SPACE, but if N is specified, it becomes the new window
55 Like SPACE, but scrolls a full screenful, even if it reaches
56 end-of-file in the process.
58 ENTER or RETURN or ^N or e or ^E or j or ^J
59 Scroll forward N lines, default 1. The entire N lines are dis-
60 played, even if N is more than the screen size.
63 Scroll forward N lines, default one half of the screen size. If
64 N is specified, it becomes the new default for subsequent d and
68 Scroll backward N lines, default one window (see option -z
69 below). If N is more than the screen size, only the final
70 screenful is displayed.
72 w Like ESC-v, but if N is specified, it becomes the new window
75 y or ^Y or ^P or k or ^K
76 Scroll backward N lines, default 1. The entire N lines are dis-
77 played, even if N is more than the screen size. Warning: some
78 systems use ^Y as a special job control character.
81 Scroll backward N lines, default one half of the screen size.
82 If N is specified, it becomes the new default for subsequent d
85 J Like j, but continues to scroll beyond the end of the file.
87 K or Y Like k, but continues to scroll beyond the beginning of the
91 Scroll horizontally right N characters, default half the screen
92 width (see the -# option). If a number N is specified, it
93 becomes the default for future RIGHTARROW and LEFTARROW com-
94 mands. While the text is scrolled, it acts as though the -S
95 option (chop lines) were in effect.
98 Scroll horizontally left N characters, default half the screen
99 width (see the -# option). If a number N is specified, it
100 becomes the default for future RIGHTARROW and LEFTARROW com-
106 R Repaint the screen, discarding any buffered input. Useful if
107 the file is changing while it is being viewed.
109 F Scroll forward, and keep trying to read when the end of file is
110 reached. Normally this command would be used when already at
111 the end of the file. It is a way to monitor the tail of a file
112 which is growing while it is being viewed. (The behavior is
113 similar to the "tail -f" command.)
115 ESC-F Like F, but as soon as a line is found which matches the last
116 search pattern, the terminal bell is rung and forward scrolling
120 Go to line N in the file, default 1 (beginning of file). (Warn-
121 ing: this may be slow if N is large.)
124 Go to line N in the file, default the end of the file. (Warn-
125 ing: this may be slow if N is large, or if N is not specified
126 and standard input, rather than a file, is being read.)
128 ESC-G Same as G, except if no number N is specified and the input is
129 standard input, goes to the last line which is currently
132 p or % Go to a position N percent into the file. N should be between 0
133 and 100, and may contain a decimal point.
135 P Go to the line containing byte offset N in the file.
137 { If a left curly bracket appears in the top line displayed on the
138 screen, the { command will go to the matching right curly
139 bracket. The matching right curly bracket is positioned on the
140 bottom line of the screen. If there is more than one left curly
141 bracket on the top line, a number N may be used to specify the
142 N-th bracket on the line.
144 } If a right curly bracket appears in the bottom line displayed on
145 the screen, the } command will go to the matching left curly
146 bracket. The matching left curly bracket is positioned on the
147 top line of the screen. If there is more than one right curly
148 bracket on the top line, a number N may be used to specify the
149 N-th bracket on the line.
151 ( Like {, but applies to parentheses rather than curly brackets.
153 ) Like }, but applies to parentheses rather than curly brackets.
155 [ Like {, but applies to square brackets rather than curly brack-
158 ] Like }, but applies to square brackets rather than curly brack-
161 ESC-^F Followed by two characters, acts like {, but uses the two char-
162 acters as open and close brackets, respectively. For example,
163 "ESC ^F < >" could be used to go forward to the > which matches
164 the < in the top displayed line.
166 ESC-^B Followed by two characters, acts like }, but uses the two char-
167 acters as open and close brackets, respectively. For example,
168 "ESC ^B < >" could be used to go backward to the < which matches
169 the > in the bottom displayed line.
171 m Followed by any lowercase letter, marks the current position
174 ' (Single quote.) Followed by any lowercase letter, returns to
175 the position which was previously marked with that letter. Fol-
176 lowed by another single quote, returns to the position at which
177 the last "large" movement command was executed. Followed by a ^
178 or $, jumps to the beginning or end of the file respectively.
179 Marks are preserved when a new file is examined, so the ' com-
180 mand can be used to switch between input files.
182 ^X^X Same as single quote.
185 Search forward in the file for the N-th line containing the pat-
186 tern. N defaults to 1. The pattern is a regular expression, as
187 recognized by the regular expression library supplied by your
188 system. The search starts at the first line displayed (but see
189 the -a and -j options, which change this).
191 Certain characters are special if entered at the beginning of
192 the pattern; they modify the type of search rather than become
196 Search for lines which do NOT match the pattern.
199 Search multiple files. That is, if the search reaches
200 the END of the current file without finding a match, the
201 search continues in the next file in the command line
205 Begin the search at the first line of the FIRST file in
206 the command line list, regardless of what is currently
207 displayed on the screen or the settings of the -a or -j
210 ^K Highlight any text which matches the pattern on the cur-
211 rent screen, but don't move to the first match (KEEP cur-
214 ^R Don't interpret regular expression metacharacters; that
215 is, do a simple textual comparison.
218 Search backward in the file for the N-th line containing the
219 pattern. The search starts at the last line displayed (but see
220 the -a and -j options, which change this).
222 Certain characters are special as in the / command:
225 Search for lines which do NOT match the pattern.
228 Search multiple files. That is, if the search reaches
229 the beginning of the current file without finding a
230 match, the search continues in the previous file in the
234 Begin the search at the last line of the last file in the
235 command line list, regardless of what is currently dis-
236 played on the screen or the settings of the -a or -j
239 ^K As in forward searches.
241 ^R As in forward searches.
249 n Repeat previous search, for N-th line containing the last pat-
250 tern. If the previous search was modified by ^N, the search is
251 made for the N-th line NOT containing the pattern. If the pre-
252 vious search was modified by ^E, the search continues in the
253 next (or previous) file if not satisfied in the current file.
254 If the previous search was modified by ^R, the search is done
255 without using regular expressions. There is no effect if the
256 previous search was modified by ^F or ^K.
258 N Repeat previous search, but in the reverse direction.
260 ESC-n Repeat previous search, but crossing file boundaries. The
261 effect is as if the previous search were modified by *.
263 ESC-N Repeat previous search, but in the reverse direction and cross-
266 ESC-u Undo search highlighting. Turn off highlighting of strings
267 matching the current search pattern. If highlighting is already
268 off because of a previous ESC-u command, turn highlighting back
269 on. Any search command will also turn highlighting back on.
270 (Highlighting can also be disabled by toggling the -G option; in
271 that case search commands do not turn highlighting back on.)
274 Display only lines which match the pattern; lines which do not
275 match the pattern are not displayed. If pattern is empty (if
276 you type & immediately followed by ENTER), any filtering is
277 turned off, and all lines are displayed. While filtering is in
278 effect, an ampersand is displayed at the beginning of the
279 prompt, as a reminder that some lines in the file may be hidden.
281 Certain characters are special as in the / command:
284 Display only lines which do NOT match the pattern.
286 ^R Don't interpret regular expression metacharacters; that
287 is, do a simple textual comparison.
290 Examine a new file. If the filename is missing, the "current"
291 file (see the :n and :p commands below) from the list of files
292 in the command line is re-examined. A percent sign (%) in the
293 filename is replaced by the name of the current file. A pound
294 sign (#) is replaced by the name of the previously examined
295 file. However, two consecutive percent signs are simply
296 replaced with a single percent sign. This allows you to enter a
297 filename that contains a percent sign in the name. Similarly,
298 two consecutive pound signs are replaced with a single pound
299 sign. The filename is inserted into the command line list of
300 files so that it can be seen by subsequent :n and :p commands.
301 If the filename consists of several files, they are all inserted
302 into the list of files and the first one is examined. If the
303 filename contains one or more spaces, the entire filename should
304 be enclosed in double quotes (also see the -" option).
307 Same as :e. Warning: some systems use ^V as a special literal-
308 ization character. On such systems, you may not be able to use
311 :n Examine the next file (from the list of files given in the com-
312 mand line). If a number N is specified, the N-th next file is
315 :p Examine the previous file in the command line list. If a number
316 N is specified, the N-th previous file is examined.
318 :x Examine the first file in the command line list. If a number N
319 is specified, the N-th file in the list is examined.
321 :d Remove the current file from the list of files.
323 t Go to the next tag, if there were more than one matches for the
324 current tag. See the -t option for more details about tags.
326 T Go to the previous tag, if there were more than one matches for
330 Prints some information about the file being viewed, including
331 its name and the line number and byte offset of the bottom line
332 being displayed. If possible, it also prints the length of the
333 file, the number of lines in the file and the percent of the
334 file above the last displayed line.
336 - Followed by one of the command line option letters (see OPTIONS
337 below), this will change the setting of that option and print a
338 message describing the new setting. If a ^P (CONTROL-P) is
339 entered immediately after the dash, the setting of the option is
340 changed but no message is printed. If the option letter has a
341 numeric value (such as -b or -h), or a string value (such as -P
342 or -t), a new value may be entered after the option letter. If
343 no new value is entered, a message describing the current set-
344 ting is printed and nothing is changed.
346 -- Like the - command, but takes a long option name (see OPTIONS
347 below) rather than a single option letter. You must press ENTER
348 or RETURN after typing the option name. A ^P immediately after
349 the second dash suppresses printing of a message describing the
350 new setting, as in the - command.
352 -+ Followed by one of the command line option letters this will
353 reset the option to its default setting and print a message
354 describing the new setting. (The "-+
\e[4mX
\e[24m" command does the same
355 thing as "-+
\e[4mX
\e[24m" on the command line.) This does not work for
356 string-valued options.
358 --+ Like the -+ command, but takes a long option name rather than a
359 single option letter.
361 -! Followed by one of the command line option letters, this will
362 reset the option to the "opposite" of its default setting and
363 print a message describing the new setting. This does not work
364 for numeric or string-valued options.
366 --! Like the -! command, but takes a long option name rather than a
367 single option letter.
369 _ (Underscore.) Followed by one of the command line option let-
370 ters, this will print a message describing the current setting
371 of that option. The setting of the option is not changed.
373 __ (Double underscore.) Like the _ (underscore) command, but takes
374 a long option name rather than a single option letter. You must
375 press ENTER or RETURN after typing the option name.
377 +cmd Causes the specified cmd to be executed each time a new file is
378 examined. For example, +G causes
\e[4mless
\e[24m to initially display each
379 file starting at the end rather than the beginning.
381 V Prints the version number of
\e[4mless
\e[24m being run.
383 q or Q or :q or :Q or ZZ
384 Exits
\e[4mless.
\e[0m
386 The following four commands may or may not be valid, depending on your
387 particular installation.
389 v Invokes an editor to edit the current file being viewed. The
390 editor is taken from the environment variable VISUAL if defined,
391 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei-
392 ther VISUAL nor EDITOR is defined. See also the discussion of
393 LESSEDIT under the section on PROMPTS below.
396 Invokes a shell to run the shell-command given. A percent sign
397 (%) in the command is replaced by the name of the current file.
398 A pound sign (#) is replaced by the name of the previously exam-
399 ined file. "!!" repeats the last shell command. "!" with no
400 shell command simply invokes a shell. On Unix systems, the
401 shell is taken from the environment variable SHELL, or defaults
402 to "sh". On MS-DOS and OS/2 systems, the shell is the normal
406 <m> represents any mark letter. Pipes a section of the input
407 file to the given shell command. The section of the file to be
408 piped is between the first line on the current screen and the
409 position marked by the letter. <m> may also be ^ or $ to indi-
410 cate beginning or end of file respectively. If <m> is . or new-
411 line, the current screen is piped.
414 Save the input to a file. This only works if the input is a
415 pipe, not an ordinary file.
418 Command line options are described below. Most options may be changed
419 while
\e[4mless
\e[24m is running, via the "-" command.
421 Most options may be given in one of two forms: either a dash followed
422 by a single letter, or two dashes followed by a long option name. A
423 long option name may be abbreviated as long as the abbreviation is
424 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but
425 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some
426 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct
427 from --quit-at-eof. Such option names need only have their first let-
428 ter capitalized; the remainder of the name may be in either case. For
429 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
431 Options are also taken from the environment variable "LESS". For exam-
432 ple, to avoid typing "less -options ..." each time
\e[4mless
\e[24m is invoked, you
433 might tell
\e[4mcsh:
\e[0m
435 setenv LESS "-options"
437 or if you use
\e[4msh:
\e[0m
439 LESS="-options"; export LESS
441 On MS-DOS, you don't need the quotes, but you should replace any per-
442 cent signs in the options string by double percent signs.
444 The environment variable is parsed before the command line, so command
445 line options override the LESS environment variable. If an option
446 appears in the LESS variable, it can be reset to its default value on
447 the command line by beginning the command line option with "-+".
449 Some options like -k or -D require a string to follow the option let-
450 ter. The string for that option is considered to end when a dollar
451 sign ($) is found. For example, you can set two -D options on MS-DOS
456 If the --use-backslash option appears earlier in the options, then a
457 dollar sign or backslash may be included literally in an option string
458 by preceding it with a backslash. If the --use-backslash option is not
459 in effect, then backslashes are not treated specially, and there is no
460 way to include a dollar sign in the option string.
463 This option displays a summary of the commands accepted by
\e[4mless
\e[0m
464 (the same as the h command). (Depending on how your shell
465 interprets the question mark, it may be necessary to quote the
466 question mark, thus: "-\?".)
468 -a or --search-skip-screen
469 By default, forward searches start at the top of the displayed
470 screen and backwards searches start at the bottom of the dis-
471 played screen (except for repeated searches invoked by the n or
472 N commands, which start after or before the "target" line
473 respectively; see the -j option for more about the target line).
474 The -a option causes forward searches to instead start at the
475 bottom of the screen and backward searches to start at the top
476 of the screen, thus skipping all lines displayed on the screen.
478 -A or --SEARCH-SKIP-SCREEN
479 Causes all forward searches (not just non-repeated searches) to
480 start just after the target line, and all backward searches to
481 start just before the target line. Thus, forward searches will
482 skip part of the displayed screen (from the first line up to and
483 including the target line). Similarly backwards searches will
484 skip the displayed screen from the last line up to and including
485 the target line. This was the default behavior in less versions
488 -b
\e[4mn
\e[24m or --buffers=
\e[4mn
\e[0m
489 Specifies the amount of buffer space
\e[4mless
\e[24m will use for each
490 file, in units of kilobytes (1024 bytes). By default 64 K of
491 buffer space is used for each file (unless the file is a pipe;
492 see the -B option). The -b option specifies instead that
\e[4mn
\e[0m
493 kilobytes of buffer space should be used for each file. If
\e[4mn
\e[24m is
494 -1, buffer space is unlimited; that is, the entire file can be
498 By default, when data is read from a pipe, buffers are allocated
499 automatically as needed. If a large amount of data is read from
500 the pipe, this can cause a large amount of memory to be allo-
501 cated. The -B option disables this automatic allocation of buf-
502 fers for pipes, so that only 64 K (or the amount of space speci-
503 fied by the -b option) is used for the pipe. Warning: use of -B
504 can result in erroneous display, since only the most recently
505 viewed part of the piped data is kept in memory; any earlier
509 Causes full screen repaints to be painted from the top line
510 down. By default, full screen repaints are done by scrolling
511 from the bottom of the screen.
514 Same as -c, for compatibility with older versions of
\e[4mless.
\e[0m
517 The -d option suppresses the error message normally displayed if
518 the terminal is dumb; that is, lacks some important capability,
519 such as the ability to clear the screen or scroll backward. The
520 -d option does not otherwise change the behavior of
\e[4mless
\e[24m on a
523 -D
\e[1mx
\e[4m
\e[22mcolor
\e[24m or --color=
\e[1mx
\e[4m
\e[22mcolor
\e[0m
524 [MS-DOS only] Sets the color of the text displayed.
\e[1mx
\e[22mis a sin-
525 gle character which selects the type of text whose color is
526 being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
527 \e[4mcolor
\e[24m is a pair of numbers separated by a period. The first
528 number selects the foreground color and the second selects the
529 background color of the text. A single number
\e[4mN
\e[24m is the same as
530 \e[4mN.M
\e[24m, where
\e[4mM
\e[24m is the normal background color.
534 Causes
\e[4mless
\e[24m to automatically exit the second time it reaches
535 end-of-file. By default, the only way to exit
\e[4mless
\e[24m is via the
539 Causes
\e[4mless
\e[24m to automatically exit the first time it reaches end-
543 Forces non-regular files to be opened. (A non-regular file is a
544 directory or a device special file.) Also suppresses the warn-
545 ing message when a binary file is opened. By default,
\e[4mless
\e[24m will
546 refuse to open non-regular files. Note that some operating sys-
547 tems will not allow directories to be read, even if -f is set.
549 -F or --quit-if-one-screen
550 Causes
\e[4mless
\e[24m to automatically exit if the entire file can be dis-
551 played on the first screen.
553 -g or --hilite-search
554 Normally,
\e[4mless
\e[24m will highlight ALL strings which match the last
555 search command. The -g option changes this behavior to high-
556 light only the particular string which was found by the last
557 search command. This can cause
\e[4mless
\e[24m to run somewhat faster than
560 -G or --HILITE-SEARCH
561 The -G option suppresses all highlighting of strings found by
564 -h
\e[4mn
\e[24m or --max-back-scroll=
\e[4mn
\e[0m
565 Specifies a maximum number of lines to scroll backward. If it
566 is necessary to scroll backward more than
\e[4mn
\e[24m lines, the screen is
567 repainted in a forward direction instead. (If the terminal does
568 not have the ability to scroll backward, -h0 is implied.)
571 Causes searches to ignore case; that is, uppercase and lowercase
572 are considered identical. This option is ignored if any upper-
573 case letters appear in the search pattern; in other words, if a
574 pattern contains uppercase letters, then that search does not
578 Like -i, but searches ignore case even if the pattern contains
581 -j
\e[4mn
\e[24m or --jump-target=
\e[4mn
\e[0m
582 Specifies a line on the screen where the "target" line is to be
583 positioned. The target line is the line specified by any com-
584 mand to search for a pattern, jump to a line number, jump to a
585 file percentage or jump to a tag. The screen line may be speci-
586 fied by a number: the top line on the screen is 1, the next is
587 2, and so on. The number may be negative to specify a line rel-
588 ative to the bottom of the screen: the bottom line on the screen
589 is -1, the second to the bottom is -2, and so on. Alternately,
590 the screen line may be specified as a fraction of the height of
591 the screen, starting with a decimal point: .5 is in the middle
592 of the screen, .3 is three tenths down from the first line, and
593 so on. If the line is specified as a fraction, the actual line
594 number is recalculated if the terminal window is resized, so
595 that the target line remains at the specified fraction of the
596 screen height. If any form of the -j option is used, repeated
597 forward searches (invoked with "n" or "N") begin at the line
598 immediately after the target line, and repeated backward
599 searches begin at the target line, unless changed by -a or -A.
600 For example, if "-j4" is used, the target line is the fourth
601 line on the screen, so forward searches begin at the fifth line
602 on the screen. However nonrepeated searches (invoked with "/"
603 or "?") always begin at the start or end of the current screen
606 -J or --status-column
607 Displays a status column at the left edge of the screen. The
608 status column shows the lines that matched the current search.
609 The status column is also used if the -w or -W option is in
612 -k
\e[4mfilename
\e[24m or --lesskey-file=
\e[4mfilename
\e[0m
613 Causes
\e[4mless
\e[24m to open and interpret the named file as a
\e[4mlesskey
\e[0m
614 (1) file. Multiple -k options may be specified. If the LESSKEY
615 or LESSKEY_SYSTEM environment variable is set, or if a lesskey
616 file is found in a standard place (see KEY BINDINGS), it is also
617 used as a
\e[4mlesskey
\e[24m file.
620 Causes
\e[4mless
\e[24m to exit immediately (with status 2) when an inter-
621 rupt character (usually ^C) is typed. Normally, an interrupt
622 character causes
\e[4mless
\e[24m to stop whatever it is doing and return to
623 its command prompt. Note that use of this option makes it
624 impossible to return to the command prompt from the "F" command.
627 Ignore the LESSOPEN environment variable (see the INPUT PRE-
628 PROCESSOR section below). This option can be set from within
629 \e[4mless
\e[24m, but it will apply only to files opened subsequently, not
630 to the file which is currently open.
633 Causes
\e[4mless
\e[24m to prompt verbosely (like
\e[4mmore
\e[24m), with the percent
634 into the file. By default,
\e[4mless
\e[24m prompts with a colon.
637 Causes
\e[4mless
\e[24m to prompt even more verbosely than
\e[4mmore.
\e[0m
640 Suppresses line numbers. The default (to use line numbers) may
641 cause
\e[4mless
\e[24m to run more slowly in some cases, especially with a
642 very large input file. Suppressing line numbers with the -n
643 option will avoid this problem. Using line numbers means: the
644 line number will be displayed in the verbose prompt and in the =
645 command, and the v command will pass the current line number to
646 the editor (see also the discussion of LESSEDIT in PROMPTS
650 Causes a line number to be displayed at the beginning of each
653 -o
\e[4mfilename
\e[24m or --log-file=
\e[4mfilename
\e[0m
654 Causes
\e[4mless
\e[24m to copy its input to the named file as it is being
655 viewed. This applies only when the input file is a pipe, not an
656 ordinary file. If the file already exists,
\e[4mless
\e[24m will ask for
657 confirmation before overwriting it.
659 -O
\e[4mfilename
\e[24m or --LOG-FILE=
\e[4mfilename
\e[0m
660 The -O option is like -o, but it will overwrite an existing file
661 without asking for confirmation.
663 If no log file has been specified, the -o and -O options can be
664 used from within
\e[4mless
\e[24m to specify a log file. Without a file
665 name, they will simply report the name of the log file. The "s"
666 command is equivalent to specifying -o from within
\e[4mless.
\e[0m
668 -p
\e[4mpattern
\e[24m or --pattern=
\e[4mpattern
\e[0m
669 The -p option on the command line is equivalent to specifying
670 +/
\e[4mpattern
\e[24m; that is, it tells
\e[4mless
\e[24m to start at the first occur-
671 rence of
\e[4mpattern
\e[24m in the file.
673 -P
\e[4mprompt
\e[24m or --prompt=
\e[4mprompt
\e[0m
674 Provides a way to tailor the three prompt styles to your own
675 preference. This option would normally be put in the LESS envi-
676 ronment variable, rather than being typed in with each
\e[4mless
\e[24m com-
677 mand. Such an option must either be the last option in the LESS
678 variable, or be terminated by a dollar sign.
679 -Ps followed by a string changes the default (short) prompt to
681 -Pm changes the medium (-m) prompt.
682 -PM changes the long (-M) prompt.
683 -Ph changes the prompt for the help screen.
684 -P= changes the message printed by the = command.
685 -Pw changes the message printed while waiting for data (in the
686 F command). All prompt strings consist of a sequence of letters
687 and special escape sequences. See the section on PROMPTS for
690 -q or --quiet or --silent
691 Causes moderately "quiet" operation: the terminal bell is not
692 rung if an attempt is made to scroll past the end of the file or
693 before the beginning of the file. If the terminal has a "visual
694 bell", it is used instead. The bell will be rung on certain
695 other errors, such as typing an invalid character. The default
696 is to ring the terminal bell in all such cases.
698 -Q or --QUIET or --SILENT
699 Causes totally "quiet" operation: the terminal bell is never
702 -r or --raw-control-chars
703 Causes "raw" control characters to be displayed. The default is
704 to display control characters using the caret notation; for
705 example, a control-A (octal 001) is displayed as "^A". Warning:
706 when the -r option is used,
\e[4mless
\e[24m cannot keep track of the actual
707 appearance of the screen (since this depends on how the screen
708 responds to each type of control character). Thus, various dis-
709 play problems may result, such as long lines being split in the
712 -R or --RAW-CONTROL-CHARS
713 Like -r, but only ANSI "color" escape sequences are output in
714 "raw" form. Unlike -r, the screen appearance is maintained cor-
715 rectly in most cases. ANSI "color" escape sequences are
716 sequences of the form:
720 where the "..." is zero or more color specification characters
721 For the purpose of keeping track of screen appearance, ANSI
722 color escape sequences are assumed to not move the cursor. You
723 can make
\e[4mless
\e[24m think that characters other than "m" can end ANSI
724 color escape sequences by setting the environment variable
725 LESSANSIENDCHARS to the list of characters which can end a color
726 escape sequence. And you can make
\e[4mless
\e[24m think that characters
727 other than the standard ones may appear between the ESC and the
728 m by setting the environment variable LESSANSIMIDCHARS to the
729 list of characters which can appear.
731 -s or --squeeze-blank-lines
732 Causes consecutive blank lines to be squeezed into a single
733 blank line. This is useful when viewing
\e[4mnroff
\e[24m output.
735 -S or --chop-long-lines
736 Causes lines longer than the screen width to be chopped (trun-
737 cated) rather than wrapped. That is, the portion of a long line
738 that does not fit in the screen width is not shown. The default
739 is to wrap long lines; that is, display the remainder on the
742 -t
\e[4mtag
\e[24m or --tag=
\e[4mtag
\e[0m
743 The -t option, followed immediately by a TAG, will edit the file
744 containing that tag. For this to work, tag information must be
745 available; for example, there may be a file in the current
746 directory called "tags", which was previously built by
\e[4mctags
\e[24m (1)
747 or an equivalent command. If the environment variable LESSGLOB-
748 ALTAGS is set, it is taken to be the name of a command compati-
749 ble with
\e[4mglobal
\e[24m (1), and that command is executed to find the
750 tag. (See http://www.gnu.org/software/global/global.html). The
751 -t option may also be specified from within
\e[4mless
\e[24m (using the -
752 command) as a way of examining a new file. The command ":t" is
753 equivalent to specifying -t from within
\e[4mless.
\e[0m
755 -T
\e[4mtagsfile
\e[24m or --tag-file=
\e[4mtagsfile
\e[0m
756 Specifies a tags file to be used instead of "tags".
758 -u or --underline-special
759 Causes backspaces and carriage returns to be treated as print-
760 able characters; that is, they are sent to the terminal when
761 they appear in the input.
763 -U or --UNDERLINE-SPECIAL
764 Causes backspaces, tabs and carriage returns to be treated as
765 control characters; that is, they are handled as specified by
768 By default, if neither -u nor -U is given, backspaces which
769 appear adjacent to an underscore character are treated spe-
770 cially: the underlined text is displayed using the terminal's
771 hardware underlining capability. Also, backspaces which appear
772 between two identical characters are treated specially: the
773 overstruck text is printed using the terminal's hardware bold-
774 face capability. Other backspaces are deleted, along with the
775 preceding character. Carriage returns immediately followed by a
776 newline are deleted. Other carriage returns are handled as
777 specified by the -r option. Text which is overstruck or under-
778 lined can be searched for if neither -u nor -U is in effect.
781 Displays the version number of
\e[4mless.
\e[0m
783 -w or --hilite-unread
784 Temporarily highlights the first "new" line after a forward
785 movement of a full page. The first "new" line is the line imme-
786 diately following the line previously at the bottom of the
787 screen. Also highlights the target line after a g or p command.
788 The highlight is removed at the next command which causes move-
789 ment. The entire line is highlighted, unless the -J option is
790 in effect, in which case only the status column is highlighted.
792 -W or --HILITE-UNREAD
793 Like -w, but temporarily highlights the first new line after any
794 forward movement command larger than one line.
796 -x
\e[4mn
\e[24m,... or --tabs=
\e[4mn
\e[24m,...
797 Sets tab stops. If only one
\e[4mn
\e[24m is specified, tab stops are set
798 at multiples of
\e[4mn
\e[24m. If multiple values separated by commas are
799 specified, tab stops are set at those positions, and then con-
800 tinue with the same spacing as the last two. For example,
801 \e[4m-x9,17
\e[24m will set tabs at positions 9, 17, 25, 33, etc. The
802 default for
\e[4mn
\e[24m is 8.
805 Disables sending the termcap initialization and deinitialization
806 strings to the terminal. This is sometimes desirable if the
807 deinitialization string does something unnecessary, like clear-
810 -y
\e[4mn
\e[24m or --max-forw-scroll=
\e[4mn
\e[0m
811 Specifies a maximum number of lines to scroll forward. If it is
812 necessary to scroll forward more than
\e[4mn
\e[24m lines, the screen is
813 repainted instead. The -c or -C option may be used to repaint
814 from the top of the screen if desired. By default, any forward
815 movement causes scrolling.
817 -[z]
\e[4mn
\e[24m or --window=
\e[4mn
\e[0m
818 Changes the default scrolling window size to
\e[4mn
\e[24m lines. The
819 default is one screenful. The z and w commands can also be used
820 to change the window size. The "z" may be omitted for compati-
821 bility with some versions of
\e[4mmore.
\e[24m If the number
\e[4mn
\e[24m is negative,
822 it indicates
\e[4mn
\e[24m lines less than the current screen size. For
823 example, if the screen is 24 lines,
\e[4m-z-4
\e[24m sets the scrolling win-
824 dow to 20 lines. If the screen is resized to 40 lines, the
825 scrolling window automatically changes to 36 lines.
827 -
\e[4m"cc
\e[24m or --quotes=
\e[4mcc
\e[0m
828 Changes the filename quoting character. This may be necessary
829 if you are trying to name a file which contains both spaces and
830 quote characters. Followed by a single character, this changes
831 the quote character to that character. Filenames containing a
832 space should then be surrounded by that character rather than by
833 double quotes. Followed by two characters, changes the open
834 quote to the first character, and the close quote to the second
835 character. Filenames containing a space should then be preceded
836 by the open quote character and followed by the close quote
837 character. Note that even after the quote characters are
838 changed, this option remains -" (a dash followed by a double
842 Normally lines after end of file are displayed as a single tilde
843 (~). This option causes lines after end of file to be displayed
847 Specifies the default number of positions to scroll horizontally
848 in the RIGHTARROW and LEFTARROW commands. If the number speci-
849 fied is zero, it sets the default number of positions to one
850 half of the screen width. Alternately, the number may be speci-
851 fied as a fraction of the width of the screen, starting with a
852 decimal point: .5 is half of the screen width, .3 is three
853 tenths of the screen width, and so on. If the number is speci-
854 fied as a fraction, the actual number of scroll positions is
855 recalculated if the terminal window is resized, so that the
856 actual scroll remains at the specified fraction of the screen
860 Normally, if the input file is renamed while an F command is
861 executing,
\e[4mless
\e[24m will continue to display the contents of the
862 original file despite its name change. If --follow-name is
863 specified, during an F command
\e[4mless
\e[24m will periodically attempt to
864 reopen the file by name. If the reopen succeeds and the file is
865 a different file from the original (which means that a new file
866 has been created with the same name as the original (now
867 renamed) file),
\e[4mless
\e[24m will display the contents of that new file.
870 Disables sending the keypad initialization and deinitialization
871 strings to the terminal. This is sometimes useful if the keypad
872 strings make the numeric keypad behave in an undesirable manner.
875 This option changes the interpretations of options which follow
876 this one. After the --use-backslash option, any backslash in an
877 option string is removed and the following character is taken
878 literally. This allows a dollar sign to be included in option
881 -- A command line argument of "--" marks the end of option argu-
882 ments. Any arguments following this are interpreted as file-
883 names. This can be useful when viewing a file whose name begins
886 + If a command line option begins with
\e[1m+
\e[22m, the remainder of that
887 option is taken to be an initial command to
\e[4mless.
\e[24m For example,
888 +G tells
\e[4mless
\e[24m to start at the end of the file rather than the
889 beginning, and +/xyz tells it to start at the first occurrence
890 of "xyz" in the file. As a special case, +<number> acts like
891 +<number>g; that is, it starts the display at the specified line
892 number (however, see the caveat under the "g" command above).
893 If the option starts with ++, the initial command applies to
894 every file being viewed, not just the first one. The + command
895 described previously may also be used to set (or change) an ini-
896 tial command for every file.
899 \e[1mLINE EDITING
\e[0m
900 When entering command line at the bottom of the screen (for example, a
901 filename for the :e command, or the pattern for a search command), cer-
902 tain keys can be used to manipulate the command line. Most commands
903 have an alternate form in [ brackets ] which can be used if a key does
904 not exist on a particular keyboard. (Note that the forms beginning
905 with ESC do not work in some MS-DOS and Windows systems because ESC is
906 the line erase character.) Any of these special keys may be entered
907 literally by preceding it with the "literal" character, either ^V or
908 ^A. A backslash itself may also be entered literally by entering two
912 Move the cursor one space to the left.
915 Move the cursor one space to the right.
917 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
918 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur-
919 sor one word to the left.
921 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
922 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur-
923 sor one word to the right.
926 Move the cursor to the beginning of the line.
929 Move the cursor to the end of the line.
932 Delete the character to the left of the cursor, or cancel the
933 command if the command line is empty.
936 Delete the character under the cursor.
938 ^BACKSPACE [ ESC-BACKSPACE ]
939 (That is, CONTROL and BACKSPACE simultaneously.) Delete the
940 word to the left of the cursor.
942 ^DELETE [ ESC-X or ESC-DELETE ]
943 (That is, CONTROL and DELETE simultaneously.) Delete the word
947 Retrieve the previous command line. If you first enter some
948 text and then press UPARROW, it will retrieve the previous com-
949 mand which begins with that text.
952 Retrieve the next command line. If you first enter some text
953 and then press DOWNARROW, it will retrieve the next command
954 which begins with that text.
956 TAB Complete the partial filename to the left of the cursor. If it
957 matches more than one filename, the first match is entered into
958 the command line. Repeated TABs will cycle thru the other
959 matching filenames. If the completed filename is a directory, a
960 "/" is appended to the filename. (On MS-DOS systems, a "\" is
961 appended.) The environment variable LESSSEPARATOR can be used
962 to specify a different character to append to a directory name.
965 Like, TAB, but cycles in the reverse direction thru the matching
968 ^L Complete the partial filename to the left of the cursor. If it
969 matches more than one filename, all matches are entered into the
970 command line (if they fit).
972 ^U (Unix and OS/2) or ESC (MS-DOS)
973 Delete the entire command line, or cancel the command if the
974 command line is empty. If you have changed your line-kill char-
975 acter in Unix to something other than ^U, that character is used
978 ^G Delete the entire command line and return to the main prompt.
981 \e[1mKEY BINDINGS
\e[0m
982 You may define your own
\e[4mless
\e[24m commands by using the program
\e[4mlesskey
\e[24m (1)
983 to create a lesskey file. This file specifies a set of command keys
984 and an action associated with each key. You may also use
\e[4mlesskey
\e[24m to
985 change the line-editing keys (see LINE EDITING), and to set environment
986 variables. If the environment variable LESSKEY is set,
\e[4mless
\e[24m uses that
987 as the name of the lesskey file. Otherwise,
\e[4mless
\e[24m looks in a standard
988 place for the lesskey file: On Unix systems,
\e[4mless
\e[24m looks for a lesskey
989 file called "$HOME/.less". On MS-DOS and Windows systems,
\e[4mless
\e[24m looks
990 for a lesskey file called "$HOME/_less", and if it is not found there,
991 then looks for a lesskey file called "_less" in any directory specified
992 in the PATH environment variable. On OS/2 systems,
\e[4mless
\e[24m looks for a
993 lesskey file called "$HOME/less.ini", and if it is not found, then
994 looks for a lesskey file called "less.ini" in any directory specified
995 in the INIT environment variable, and if it not found there, then looks
996 for a lesskey file called "less.ini" in any directory specified in the
997 PATH environment variable. See the
\e[4mlesskey
\e[24m manual page for more
1000 A system-wide lesskey file may also be set up to provide key bindings.
1001 If a key is defined in both a local lesskey file and in the system-wide
1002 file, key bindings in the local file take precedence over those in the
1003 system-wide file. If the environment variable LESSKEY_SYSTEM is set,
1004 \e[4mless
\e[24m uses that as the name of the system-wide lesskey file. Otherwise,
1005 \e[4mless
\e[24m looks in a standard place for the system-wide lesskey file: On
1006 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1007 (However, if
\e[4mless
\e[24m was built with a different sysconf directory than
1008 /usr/local/etc, that directory is where the sysless file is found.) On
1009 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys-
1010 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
1013 \e[1mINPUT PREPROCESSOR
\e[0m
1014 You may define an "input preprocessor" for
\e[4mless.
\e[24m Before
\e[4mless
\e[24m opens a
1015 file, it first gives your input preprocessor a chance to modify the way
1016 the contents of the file are displayed. An input preprocessor is sim-
1017 ply an executable program (or shell script), which writes the contents
1018 of the file to a different file, called the replacement file. The con-
1019 tents of the replacement file are then displayed in place of the con-
1020 tents of the original file. However, it will appear to the user as if
1021 the original file is opened; that is,
\e[4mless
\e[24m will display the original
1022 filename as the name of the current file.
1024 An input preprocessor receives one command line argument, the original
1025 filename, as entered by the user. It should create the replacement
1026 file, and when finished, print the name of the replacement file to its
1027 standard output. If the input preprocessor does not output a replace-
1028 ment filename,
\e[4mless
\e[24m uses the original file, as normal. The input pre-
1029 processor is not called when viewing standard input. To set up an
1030 input preprocessor, set the LESSOPEN environment variable to a command
1031 line which will invoke your input preprocessor. This command line
1032 should include one occurrence of the string "%s", which will be
1033 replaced by the filename when the input preprocessor command is
1036 When
\e[4mless
\e[24m closes a file opened in such a way, it will call another pro-
1037 gram, called the input postprocessor, which may perform any desired
1038 clean-up action (such as deleting the replacement file created by
1039 LESSOPEN). This program receives two command line arguments, the orig-
1040 inal filename as entered by the user, and the name of the replacement
1041 file. To set up an input postprocessor, set the LESSCLOSE environment
1042 variable to a command line which will invoke your input postprocessor.
1043 It may include two occurrences of the string "%s"; the first is
1044 replaced with the original name of the file and the second with the
1045 name of the replacement file, which was output by LESSOPEN.
1047 For example, on many Unix systems, these two scripts will allow you to
1048 keep files in compressed format, but still let
\e[4mless
\e[24m view them directly:
1053 *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1054 if [ -s /tmp/less.$$ ]; then
1066 To use these scripts, put them both where they can be executed and set
1067 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More
1068 complex LESSOPEN and LESSCLOSE scripts may be written to accept other
1069 types of compressed files, and so on.
1071 It is also possible to set up an input preprocessor to pipe the file
1072 data directly to
\e[4mless,
\e[24m rather than putting the data into a replacement
1073 file. This avoids the need to decompress the entire file before start-
1074 ing to view it. An input preprocessor that works this way is called an
1075 input pipe. An input pipe, instead of writing the name of a replace-
1076 ment file on its standard output, writes the entire contents of the
1077 replacement file on its standard output. If the input pipe does not
1078 write any characters on its standard output, then there is no replace-
1079 ment file and
\e[4mless
\e[24m uses the original file, as normal. To use an input
1080 pipe, make the first character in the LESSOPEN environment variable a
1081 vertical bar (|) to signify that the input preprocessor is an input
1084 For example, on many Unix systems, this script will work like the pre-
1085 vious example scripts:
1090 *.Z) uncompress -c $1 2>/dev/null
1096 To use this script, put it where it can be executed and set
1097 LESSOPEN="|lesspipe.sh %s".
1099 Note that a preprocessor cannot output an empty file, since that is
1100 interpreted as meaning there is no replacement, and the original file
1101 is used. To avoid this, if LESSOPEN starts with two vertical bars, the
1102 exit status of the script becomes meaningful. If the exit status is
1103 zero, the output is considered to be replacement text, even if it
1104 empty. If the exit status is nonzero, any output is ignored and the
1105 original file is used. For compatibility with previous versions of
1106 \e[4mless,
\e[24m if LESSOPEN starts with only one vertical bar, the exit status of
1107 the preprocessor is ignored.
1109 When an input pipe is used, a LESSCLOSE postprocessor can be used, but
1110 it is usually not necessary since there is no replacement file to clean
1111 up. In this case, the replacement file name passed to the LESSCLOSE
1112 postprocessor is "-".
1114 For compatibility with previous versions of
\e[4mless,
\e[24m the input preproces-
1115 sor or pipe is not used if
\e[4mless
\e[24m is viewing standard input. However, if
1116 the first character of LESSOPEN is a dash (-), the input preprocessor
1117 is used on standard input as well as other files. In this case, the
1118 dash is not considered to be part of the preprocessor command. If
1119 standard input is being viewed, the input preprocessor is passed a file
1120 name consisting of a single dash. Similarly, if the first two charac-
1121 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars
1122 and a dash (||-), the input pipe is used on standard input as well as
1123 other files. Again, in this case the dash is not considered to be part
1124 of the input pipe command.
1127 \e[1mNATIONAL CHARACTER SETS
\e[0m
1128 There are three types of characters in the input file:
1131 can be displayed directly to the screen.
1134 should not be displayed directly, but are expected to be found
1135 in ordinary text files (such as backspace and tab).
1138 should not be displayed directly and are not expected to be
1139 found in text files.
1141 A "character set" is simply a description of which characters are to be
1142 considered normal, control, and binary. The LESSCHARSET environment
1143 variable may be used to select a character set. Possible values for
1146 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars
1147 with values between 32 and 126 are normal, and all others are
1151 Selects an ISO 8859 character set. This is the same as ASCII,
1152 except characters between 160 and 255 are treated as normal
1155 latin1 Same as iso8859.
1157 latin9 Same as iso8859.
1159 dos Selects a character set appropriate for MS-DOS.
1161 ebcdic Selects an EBCDIC character set.
1164 Selects an EBCDIC character set used by OS/390 Unix Services.
1165 This is the EBCDIC analogue of latin1. You get similar results
1166 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your
1169 koi8-r Selects a Russian character set.
1171 next Selects a character set appropriate for NeXT computers.
1173 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set.
1174 UTF-8 is special in that it supports multi-byte characters in
1175 the input file. It is the only character set that supports
1176 multi-byte characters.
1179 Selects a character set appropriate for Microsoft Windows (cp
1182 In rare cases, it may be desired to tailor
\e[4mless
\e[24m to use a character set
1183 other than the ones definable by LESSCHARSET. In this case, the envi-
1184 ronment variable LESSCHARDEF can be used to define a character set. It
1185 should be set to a string where each character in the string represents
1186 one character in the character set. The character "." is used for a
1187 normal character, "c" for control, and "b" for binary. A decimal num-
1188 ber may be used for repetition. For example, "bccc4b." would mean
1189 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are
1190 binary, and 8 is normal. All characters after the last are taken to be
1191 the same as the last, so characters 9 through 255 would be normal.
1192 (This is an example, and does not necessarily represent any real char-
1195 This table shows the value of LESSCHARDEF which is equivalent to each
1196 of the possible values for LESSCHARSET:
1198 ascii 8bcccbcc18b95.b
1199 dos 8bcccbcc12bc5b95.b.
1200 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1201 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1202 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1204 iso8859 8bcccbcc18b95.33b.
1205 koi8-r 8bcccbcc18b95.b128.
1206 latin1 8bcccbcc18b95.33b.
1207 next 8bcccbcc18b95.bb125.bb
1209 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings
1210 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or
1211 LANG environment variables, then the default character set is utf-8.
1213 If that string is not found, but your system supports the
\e[4msetlocale
\e[0m
1214 interface,
\e[4mless
\e[24m will use setlocale to determine the character set.
1215 setlocale is controlled by setting the LANG or LC_CTYPE environment
1218 Finally, if the
\e[4msetlocale
\e[24m interface is also not available, the default
1219 character set is latin1.
1221 Control and binary characters are displayed in standout (reverse
1222 video). Each such character is displayed in caret notation if possible
1223 (e.g. ^A for control-A). Caret notation is used only if inverting the
1224 0100 bit results in a normal printable character. Otherwise, the char-
1225 acter is displayed as a hex number in angle brackets. This format can
1226 be changed by setting the LESSBINFMT environment variable. LESSBINFMT
1227 may begin with a "*" and one character to select the display attribute:
1228 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1229 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal
1230 attribute is assumed. The remainder of LESSBINFMT is a string which
1231 may include one printf-style escape sequence (a % followed by x, X, o,
1232 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters
1233 are displayed in underlined hexadecimal surrounded by brackets. The
1234 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the
1235 result of expanding the character via LESSBINFMT must be less than 31
1238 When the character set is utf-8, the LESSUTFBINFMT environment variable
1239 acts similarly to LESSBINFMT but it applies to Unicode code points that
1240 were successfully decoded but are unsuitable for display (e.g., unas-
1241 signed code points). Its default value is "<U+%04lX>". Note that
1242 LESSUTFBINFMT and LESSBINFMT share their display attribute setting
1243 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after
1244 LESSBINFMT so its setting, if any, will have priority. Problematic
1245 octets in a UTF-8 file (octets of a truncated sequence, octets of a
1246 complete but non-shortest form sequence, illegal octets, and stray
1247 trailing octets) are displayed individually using LESSBINFMT so as to
1248 facilitate diagnostic of how the UTF-8 file is ill-formed.
1252 The -P option allows you to tailor the prompt to your preference. The
1253 string given to the -P option replaces the specified prompt string.
1254 Certain characters in the string are interpreted specially. The prompt
1255 mechanism is rather complicated to provide flexibility, but the ordi-
1256 nary user need not understand the details of constructing personalized
1259 A percent sign followed by a single character is expanded according to
1260 what the following character is:
1262 %b
\e[4mX
\e[24m Replaced by the byte offset into the current input file. The b
1263 is followed by a single character (shown as
\e[4mX
\e[24m above) which spec-
1264 ifies the line whose byte offset is to be used. If the charac-
1265 ter is a "t", the byte offset of the top line in the display is
1266 used, an "m" means use the middle line, a "b" means use the bot-
1267 tom line, a "B" means use the line just after the bottom line,
1268 and a "j" means use the "target" line, as specified by the -j
1271 %B Replaced by the size of the current input file.
1273 %c Replaced by the column number of the text appearing in the first
1274 column of the screen.
1276 %d
\e[4mX
\e[24m Replaced by the page number of a line in the input file. The
1277 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1279 %D Replaced by the number of pages in the input file, or equiva-
1280 lently, the page number of the last line in the input file.
1282 %E Replaced by the name of the editor (from the VISUAL environment
1283 variable, or the EDITOR environment variable if VISUAL is not
1284 defined). See the discussion of the LESSEDIT feature below.
1286 %f Replaced by the name of the current input file.
1288 %F Replaced by the last component of the name of the current input
1291 %i Replaced by the index of the current file in the list of input
1294 %l
\e[4mX
\e[24m Replaced by the line number of a line in the input file. The
1295 line to be used is determined by the
\e[4mX
\e[24m, as with the %b option.
1297 %L Replaced by the line number of the last line in the input file.
1299 %m Replaced by the total number of input files.
1301 %p
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1302 byte offsets. The line used is determined by the
\e[4mX
\e[24m as with the
1305 %P
\e[4mX
\e[24m Replaced by the percent into the current input file, based on
1306 line numbers. The line used is determined by the
\e[4mX
\e[24m as with the
1311 %t Causes any trailing spaces to be removed. Usually used at the
1312 end of the string, but may appear anywhere.
1314 %T Normally expands to the word "file". However if viewing files
1315 via a tags list using the -t option, it expands to the word
1318 %x Replaced by the name of the next input file in the list.
1320 If any item is unknown (for example, the file size if input is a pipe),
1321 a question mark is printed instead.
1323 The format of the prompt string can be changed depending on certain
1324 conditions. A question mark followed by a single character acts like
1325 an "IF": depending on the following character, a condition is evalu-
1326 ated. If the condition is true, any characters following the question
1327 mark and condition character, up to a period, are included in the
1328 prompt. If the condition is false, such characters are not included.
1329 A colon appearing between the question mark and the period can be used
1330 to establish an "ELSE": any characters between the colon and the period
1331 are included in the string if and only if the IF condition is false.
1332 Condition characters (which follow a question mark) may be:
1334 ?a True if any characters have been included in the prompt so far.
1336 ?b
\e[4mX
\e[24m True if the byte offset of the specified line is known.
1338 ?B True if the size of current input file is known.
1340 ?c True if the text is horizontally shifted (%c is not zero).
1342 ?d
\e[4mX
\e[24m True if the page number of the specified line is known.
1344 ?e True if at end-of-file.
1346 ?f True if there is an input filename (that is, if input is not a
1349 ?l
\e[4mX
\e[24m True if the line number of the specified line is known.
1351 ?L True if the line number of the last line in the file is known.
1353 ?m True if there is more than one input file.
1355 ?n True if this is the first prompt in a new input file.
1357 ?p
\e[4mX
\e[24m True if the percent into the current input file, based on byte
1358 offsets, of the specified line is known.
1360 ?P
\e[4mX
\e[24m True if the percent into the current input file, based on line
1361 numbers, of the specified line is known.
1365 ?x True if there is a next input file (that is, if the current
1366 input file is not the last one).
1368 Any characters other than the special ones (question mark, colon,
1369 period, percent, and backslash) become literally part of the prompt.
1370 Any of the special characters may be included in the prompt literally
1371 by preceding it with a backslash.
1375 ?f%f:Standard input.
1377 This prompt prints the filename, if known; otherwise the string "Stan-
1380 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1382 This prompt would print the filename, if known. The filename is fol-
1383 lowed by the line number, if known, otherwise the percent if known,
1384 otherwise the byte offset if known. Otherwise, a dash is printed.
1385 Notice how each question mark has a matching period, and how the %
1386 after the %pt is included literally by escaping it with a backslash.
1388 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
1390 This prints the filename if this is the first prompt in a file, fol-
1391 lowed by the "file N of N" message if there is more than one input
1392 file. Then, if we are at end-of-file, the string "(END)" is printed
1393 followed by the name of the next file, if there is one. Finally, any
1394 trailing spaces are truncated. This is the default prompt. For refer-
1395 ence, here are the defaults for the other two prompts (-m and -M
1396 respectively). Each is broken into two lines here for readability
1399 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
1400 ?pB%pB\%:byte %bB?s/%s...%t
1402 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
1403 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1405 And here is the default message produced by the = command:
1407 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
1408 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1410 The prompt expansion features are also used for another purpose: if an
1411 environment variable LESSEDIT is defined, it is used as the command to
1412 be executed when the v command is invoked. The LESSEDIT string is
1413 expanded in the same way as the prompt strings. The default value for
1418 Note that this expands to the editor name, followed by a + and the line
1419 number, followed by the file name. If your editor does not accept the
1420 "+linenumber" syntax, or has other differences in invocation syntax,
1421 the LESSEDIT variable can be changed to modify this default.
1425 When the environment variable LESSSECURE is set to 1,
\e[4mless
\e[24m runs in a
1426 "secure" mode. This means these features are disabled:
1432 :e the examine command.
1434 v the editing command
1438 -k use of lesskey files
1440 -t use of tags files
1442 metacharacters in filenames, such as *
1444 filename completion (TAB, ^L)
1446 Less can also be compiled to be permanently in "secure" mode.
1449 \e[1mCOMPATIBILITY WITH MORE
\e[0m
1450 If the environment variable LESS_IS_MORE is set to 1, or if the program
1451 is invoked via a file link named "more",
\e[4mless
\e[24m behaves (mostly) in con-
1452 formance with the POSIX "more" command specification. In this mode,
1453 less behaves differently in these ways:
1455 The -e option works differently. If the -e option is not set,
\e[4mless
\e[0m
1456 behaves as if the -e option were set. If the -e option is set,
\e[4mless
\e[0m
1457 behaves as if the -E option were set.
1459 The -m option works differently. If the -m option is not set, the
1460 medium prompt is used, and it is prefixed with the string "--More--".
1461 If the -m option is set, the short prompt is used.
1463 The -n option acts like the -z option. The normal behavior of the -n
1464 option is unavailable in this mode.
1466 The parameter to the -p option is taken to be a
\e[4mless
\e[24m command rather
1467 than a search pattern.
1469 The LESS environment variable is ignored, and the MORE environment
1470 variable is used in its place.
1473 \e[1mENVIRONMENT VARIABLES
\e[0m
1474 Environment variables may be specified either in the system environment
1475 as usual, or in a
\e[4mlesskey
\e[24m (1) file. If environment variables are
1476 defined in more than one place, variables defined in a local lesskey
1477 file take precedence over variables defined in the system environment,
1478 which take precedence over variables defined in the system-wide lesskey
1482 Sets the number of columns on the screen. Takes precedence over
1483 the number of columns specified by the TERM variable. (But if
1484 you have a windowing system which supports TIOCGWINSZ or
1485 WIOCGETD, the window system's idea of the screen size takes
1486 precedence over the LINES and COLUMNS environment variables.)
1488 EDITOR The name of the editor (used for the v command).
1490 HOME Name of the user's home directory (used to find a lesskey file
1491 on Unix and OS/2 systems).
1494 Concatenation of the HOMEDRIVE and HOMEPATH environment vari-
1495 ables is the name of the user's home directory if the HOME vari-
1496 able is not set (only in the Windows version).
1498 INIT Name of the user's init directory (used to find a lesskey file
1501 LANG Language for determining the character set.
1504 Language for determining the character set.
1506 LESS Options which are passed to
\e[4mless
\e[24m automatically.
1509 Characters which may end an ANSI color escape sequence (default
1513 Characters which may appear between the ESC character and the
1514 end character in an ANSI color escape sequence (default
1515 "0123456789:;[?!"'#%()*+ ".
1518 Format for displaying non-printable, non-control characters.
1521 Defines a character set.
1524 Selects a predefined character set.
1527 Command line to invoke the (optional) input-postprocessor.
1530 Name of the lessecho program (default "lessecho"). The lessecho
1531 program is needed to expand metacharacters, such as * and ?, in
1532 filenames on Unix systems.
1535 Editor prototype string (used for the v command). See discus-
1539 Name of the command used by the -t option to find global tags.
1540 Normally should be set to "global" if your system has the
\e[4mglobal
\e[0m
1541 (1) command. If not set, global tags are not used.
1544 Name of the history file used to remember search commands and
1545 shell commands between invocations of
\e[4mless.
\e[24m If set to "-" or
1546 "/dev/null", a history file is not used. The default is
1547 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and
1548 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1552 The maximum number of commands to save in the history file. The
1556 Name of the default lesskey(1) file.
1559 Name of the default system-wide lesskey(1) file.
1562 List of characters which are considered "metacharacters" by the
1566 Prefix which less will add before each metacharacter in a com-
1567 mand sent to the shell. If LESSMETAESCAPE is an empty string,
1568 commands containing metacharacters will not be passed to the
1572 Command line to invoke the (optional) input-preprocessor.
1575 Runs less in "secure" mode. See discussion under SECURITY.
1578 String to be appended to a directory name in filename comple-
1582 Format for displaying non-printable Unicode code points.
1585 Emulate the
\e[4mmore
\e[24m (1) command.
1587 LINES Sets the number of lines on the screen. Takes precedence over
1588 the number of lines specified by the TERM variable. (But if you
1589 have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1590 the window system's idea of the screen size takes precedence
1591 over the LINES and COLUMNS environment variables.)
1593 MORE Options which are passed to
\e[4mless
\e[24m automatically when running in
1594 \e[4mmore
\e[24m compatible mode.
1596 PATH User's search path (used to find a lesskey file on MS-DOS and
1599 SHELL The shell used to execute the ! command, as well as to expand
1602 TERM The type of terminal on which
\e[4mless
\e[24m is being run.
1604 VISUAL The name of the editor (used for the v command).
1612 Copyright (C) 1984-2015 Mark Nudelman
1614 less is part of the GNU project and is free software. You can redis-
1615 tribute it and/or modify it under the terms of either (1) the GNU Gen-
1616 eral Public License as published by the Free Software Foundation; or
1617 (2) the Less License. See the file README in the less distribution for
1618 more details regarding redistribution. You should have received a copy
1619 of the GNU General Public License along with the source for less; see
1620 the file COPYING. If not, write to the Free Software Foundation, 59
1621 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
1622 have received a copy of the Less License; see the file LICENSE.
1624 less is distributed in the hope that it will be useful, but WITHOUT ANY
1625 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT-
1626 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
1632 Send bug reports or comments to <bug-less@gnu.org>
1633 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list
1634 of known bugs in less.
1635 For more information, see the less homepage at
1636 http://www.greenwoodsoftware.com/less.
1640 Version 481: 31 Aug 2015 LESS(1)
projects / oss / less.git / blob