· 7 years ago · Sep 03, 2018, 02:26 AM
1LESS(1) General Commands Manual LESS(1)
2
3NAME
4 less - opposite of more
5
6SYNOPSIS
7 less -?
8 less --help
9 less -V
10 less --version
11 less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]
12 [-b space] [-h lines] [-j line] [-k keyfile]
13 [-{oO} logfile] [-p pattern] [-P prompt] [-t tag]
14 [-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]
15 [-# shift] [+[+]cmd] [--] [filename]...
16 (See the OPTIONS section for alternate option syntax with long option names.)
17
18DESCRIPTION
19 Less is a program similar to more (1), but which allows backward movement in the file as well as forward movement. Also, less does not have to read the entire input file before
20 starting, so with large input files it starts up faster than text editors like vi (1). Less uses termcap (or terminfo on some systems), so it can run on a variety of terminals.
21 There is even limited support for hardcopy terminals. (On a hardcopy terminal, lines which should be printed at the top of the screen are prefixed with a caret.)
22
23 Commands are based on both more and vi. Commands may be preceded by a decimal number, called N in the descriptions below. The number is used by some commands, as indicated.
24
25COMMANDS
26 In the following descriptions, ^X means control-X. ESC stands for the ESCAPE key; for example ESC-v means the two character sequence "ESCAPE", then "v".
27
28 h or H Help: display a summary of these commands. If you forget all the other commands, remember this one.
29
30 SPACE or ^V or f or ^F
31 Scroll forward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed. Warning: some systems use ^V
32 as a special literalization character.
33
34 z Like SPACE, but if N is specified, it becomes the new window size.
35
36 ESC-SPACE
37 Like SPACE, but scrolls a full screenful, even if it reaches end-of-file in the process.
38
39 ENTER or RETURN or ^N or e or ^E or j or ^J
40 Scroll forward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size.
41
42 d or ^D
43 Scroll forward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands.
44
45 b or ^B or ESC-v
46 Scroll backward N lines, default one window (see option -z below). If N is more than the screen size, only the final screenful is displayed.
47
48 w Like ESC-v, but if N is specified, it becomes the new window size.
49
50 y or ^Y or ^P or k or ^K
51 Scroll backward N lines, default 1. The entire N lines are displayed, even if N is more than the screen size. Warning: some systems use ^Y as a special job control charâ€
52 acter.
53
54 u or ^U
55 Scroll backward N lines, default one half of the screen size. If N is specified, it becomes the new default for subsequent d and u commands.
56
57 J Like j, but continues to scroll beyond the end of the file.
58
59 K or Y Like k, but continues to scroll beyond the beginning of the file.
60
61 ESC-) or RIGHTARROW
62 Scroll horizontally right N characters, default half the screen width (see the -# option). If a number N is specified, it becomes the default for future RIGHTARROW and
63 LEFTARROW commands. While the text is scrolled, it acts as though the -S option (chop lines) were in effect.
64
65 ESC-( or LEFTARROW
66 Scroll horizontally left N characters, default half the screen width (see the -# option). If a number N is specified, it becomes the default for future RIGHTARROW and LEFâ€
67 TARROW commands.
68
69 ESC-} or ^RIGHTARROW
70 Scroll horizontally right to show the end of the longest displayed line.
71
72 ESC-{ or ^LEFTARROW
73 Scroll horizontally left back to the first column.
74
75 r or ^R or ^L
76 Repaint the screen.
77
78 R Repaint the screen, discarding any buffered input. Useful if the file is changing while it is being viewed.
79
80 F Scroll forward, and keep trying to read when the end of file is reached. Normally this command would be used when already at the end of the file. It is a way to monitor
81 the tail of a file which is growing while it is being viewed. (The behavior is similar to the "tail -f" command.)
82
83 ESC-F Like F, but as soon as a line is found which matches the last search pattern, the terminal bell is rung and forward scrolling stops.
84
85 g or < or ESC-<
86 Go to line N in the file, default 1 (beginning of file). (Warning: this may be slow if N is large.)
87
88 G or > or ESC->
89 Go to line N in the file, default the end of the file. (Warning: this may be slow if N is large, or if N is not specified and standard input, rather than a file, is being
90 read.)
91
92 ESC-G Same as G, except if no number N is specified and the input is standard input, goes to the last line which is currently buffered.
93
94 p or % Go to a position N percent into the file. N should be between 0 and 100, and may contain a decimal point.
95
96 P Go to the line containing byte offset N in the file.
97
98 { If a left curly bracket appears in the top line displayed on the screen, the { command will go to the matching right curly bracket. The matching right curly bracket is
99 positioned on the bottom line of the screen. If there is more than one left curly bracket on the top line, a number N may be used to specify the N-th bracket on the line.
100
101 } If a right curly bracket appears in the bottom line displayed on the screen, the } command will go to the matching left curly bracket. The matching left curly bracket is
102 positioned on the top line of the screen. If there is more than one right curly bracket on the top line, a number N may be used to specify the N-th bracket on the line.
103
104 ( Like {, but applies to parentheses rather than curly brackets.
105
106 ) Like }, but applies to parentheses rather than curly brackets.
107
108 [ Like {, but applies to square brackets rather than curly brackets.
109
110 ] Like }, but applies to square brackets rather than curly brackets.
111
112 ESC-^F Followed by two characters, acts like {, but uses the two characters as open and close brackets, respectively. For example, "ESC ^F < >" could be used to go forward to the
113 > which matches the < in the top displayed line.
114
115 ESC-^B Followed by two characters, acts like }, but uses the two characters as open and close brackets, respectively. For example, "ESC ^B < >" could be used to go backward to
116 the < which matches the > in the bottom displayed line.
117
118 m Followed by any lowercase or uppercase letter, marks the first displayed line with that letter. If the status column is enabled via the -J option, the status column shows
119 the marked line.
120
121 M Acts like m, except the last displayed line is marked rather than the first displayed line.
122
123 ' (Single quote.) Followed by any lowercase or uppercase letter, returns to the position which was previously marked with that letter. Followed by another single quote,
124 returns to the position at which the last "large" movement command was executed. Followed by a ^ or $, jumps to the beginning or end of the file respectively. Marks are
125 preserved when a new file is examined, so the ' command can be used to switch between input files.
126
127 ^X^X Same as single quote.
128
129 ESC-m Followed by any lowercase or uppercase letter, clears the mark identified by that letter.
130
131 /pattern
132 Search forward in the file for the N-th line containing the pattern. N defaults to 1. The pattern is a regular expression, as recognized by the regular expression library
133 supplied by your system. The search starts at the first line displayed (but see the -a and -j options, which change this).
134
135 Certain characters are special if entered at the beginning of the pattern; they modify the type of search rather than become part of the pattern:
136
137 ^N or !
138 Search for lines which do NOT match the pattern.
139
140 ^E or *
141 Search multiple files. That is, if the search reaches the END of the current file without finding a match, the search continues in the next file in the command line
142 list.
143
144 ^F or @
145 Begin the search at the first line of the FIRST file in the command line list, regardless of what is currently displayed on the screen or the settings of the -a or
146 -j options.
147
148 ^K Highlight any text which matches the pattern on the current screen, but don't move to the first match (KEEP current position).
149
150 ^R Don't interpret regular expression metacharacters; that is, do a simple textual comparison.
151
152 ?pattern
153 Search backward in the file for the N-th line containing the pattern. The search starts at the last line displayed (but see the -a and -j options, which change this).
154
155 Certain characters are special as in the / command:
156
157 ^N or !
158 Search for lines which do NOT match the pattern.
159
160 ^E or *
161 Search multiple files. That is, if the search reaches the beginning of the current file without finding a match, the search continues in the previous file in the
162 command line list.
163
164 ^F or @
165 Begin the search at the last line of the last file in the command line list, regardless of what is currently displayed on the screen or the settings of the -a or -j
166 options.
167
168 ^K As in forward searches.
169
170 ^R As in forward searches.
171
172 ESC-/pattern
173 Same as "/*".
174
175 ESC-?pattern
176 Same as "?*".
177
178 n Repeat previous search, for N-th line containing the last pattern. If the previous search was modified by ^N, the search is made for the N-th line NOT containing the patâ€
179 tern. If the previous search was modified by ^E, the search continues in the next (or previous) file if not satisfied in the current file. If the previous search was modâ€
180 ified by ^R, the search is done without using regular expressions. There is no effect if the previous search was modified by ^F or ^K.
181
182 N Repeat previous search, but in the reverse direction.
183
184 ESC-n Repeat previous search, but crossing file boundaries. The effect is as if the previous search were modified by *.
185
186 ESC-N Repeat previous search, but in the reverse direction and crossing file boundaries.
187
188 ESC-u Undo search highlighting. Turn off highlighting of strings matching the current search pattern. If highlighting is already off because of a previous ESC-u command, turn
189 highlighting back on. Any search command will also turn highlighting back on. (Highlighting can also be disabled by toggling the -G option; in that case search commands
190 do not turn highlighting back on.)
191
192 &pattern
193 Display only lines which match the pattern; lines which do not match the pattern are not displayed. If pattern is empty (if you type & immediately followed by ENTER), any
194 filtering is turned off, and all lines are displayed. While filtering is in effect, an ampersand is displayed at the beginning of the prompt, as a reminder that some lines
195 in the file may be hidden.
196
197 Certain characters are special as in the / command:
198
199 ^N or !
200 Display only lines which do NOT match the pattern.
201
202 ^R Don't interpret regular expression metacharacters; that is, do a simple textual comparison.
203
204 :e [filename]
205 Examine a new file. If the filename is missing, the "current" file (see the :n and :p commands below) from the list of files in the command line is re-examined. A percent
206 sign (%) in the filename is replaced by the name of the current file. A pound sign (#) is replaced by the name of the previously examined file. However, two consecutive
207 percent signs are simply replaced with a single percent sign. This allows you to enter a filename that contains a percent sign in the name. Similarly, two consecutive
208 pound signs are replaced with a single pound sign. The filename is inserted into the command line list of files so that it can be seen by subsequent :n and :p commands.
209 If the filename consists of several files, they are all inserted into the list of files and the first one is examined. If the filename contains one or more spaces, the
210 entire filename should be enclosed in double quotes (also see the -" option).
211
212 ^X^V or E
213 Same as :e. Warning: some systems use ^V as a special literalization character. On such systems, you may not be able to use ^V.
214
215 :n Examine the next file (from the list of files given in the command line). If a number N is specified, the N-th next file is examined.
216
217 :p Examine the previous file in the command line list. If a number N is specified, the N-th previous file is examined.
218
219 :x Examine the first file in the command line list. If a number N is specified, the N-th file in the list is examined.
220
221 :d Remove the current file from the list of files.
222
223 t Go to the next tag, if there were more than one matches for the current tag. See the -t option for more details about tags.
224
225 T Go to the previous tag, if there were more than one matches for the current tag.
226
227 = or ^G or :f
228 Prints some information about the file being viewed, including its name and the line number and byte offset of the bottom line being displayed. If possible, it also prints
229 the length of the file, the number of lines in the file and the percent of the file above the last displayed line.
230
231 - Followed by one of the command line option letters (see OPTIONS below), this will change the setting of that option and print a message describing the new setting. If a ^P
232 (CONTROL-P) is entered immediately after the dash, the setting of the option is changed but no message is printed. If the option letter has a numeric value (such as -b or
233 -h), or a string value (such as -P or -t), a new value may be entered after the option letter. If no new value is entered, a message describing the current setting is
234 printed and nothing is changed.
235
236 -- Like the - command, but takes a long option name (see OPTIONS below) rather than a single option letter. You must press ENTER or RETURN after typing the option name. A ^P
237 immediately after the second dash suppresses printing of a message describing the new setting, as in the - command.
238
239 -+ Followed by one of the command line option letters this will reset the option to its default setting and print a message describing the new setting. (The "-+X" command
240 does the same thing as "-+X" on the command line.) This does not work for string-valued options.
241
242 --+ Like the -+ command, but takes a long option name rather than a single option letter.
243
244 -! Followed by one of the command line option letters, this will reset the option to the "opposite" of its default setting and print a message describing the new setting.
245 This does not work for numeric or string-valued options.
246
247 --! Like the -! command, but takes a long option name rather than a single option letter.
248
249 _ (Underscore.) Followed by one of the command line option letters, this will print a message describing the current setting of that option. The setting of the option is
250 not changed.
251
252 __ (Double underscore.) Like the _ (underscore) command, but takes a long option name rather than a single option letter. You must press ENTER or RETURN after typing the
253 option name.
254
255 +cmd Causes the specified cmd to be executed each time a new file is examined. For example, +G causes less to initially display each file starting at the end rather than the
256 beginning.
257
258 V Prints the version number of less being run.
259
260 q or Q or :q or :Q or ZZ
261 Exits less.
262
263 The following four commands may or may not be valid, depending on your particular installation.
264
265 v Invokes an editor to edit the current file being viewed. The editor is taken from the environment variable VISUAL if defined, or EDITOR if VISUAL is not defined, or
266 defaults to "vi" if neither VISUAL nor EDITOR is defined. See also the discussion of LESSEDIT under the section on PROMPTS below.
267
268 ! shell-command
269 Invokes a shell to run the shell-command given. A percent sign (%) in the command is replaced by the name of the current file. A pound sign (#) is replaced by the name of
270 the previously examined file. "!!" repeats the last shell command. "!" with no shell command simply invokes a shell. On Unix systems, the shell is taken from the enviâ€
271 ronment variable SHELL, or defaults to "sh". On MS-DOS and OS/2 systems, the shell is the normal command processor.
272
273 | <m> shell-command
274 <m> represents any mark letter. Pipes a section of the input file to the given shell command. The section of the file to be piped is between the position marked by the
275 letter and the current screen. The entire current screen is included, regardless of whether the marked position is before or after the current screen. <m> may also be ^
276 or $ to indicate beginning or end of file respectively. If <m> is . or newline, the current screen is piped.
277
278 s filename
279 Save the input to a file. This only works if the input is a pipe, not an ordinary file.
280
281OPTIONS
282 Command line options are described below. Most options may be changed while less is running, via the "-" command.
283
284 Most options may be given in one of two forms: either a dash followed by a single letter, or two dashes followed by a long option name. A long option name may be abbreviated as
285 long as the abbreviation is unambiguous. For example, --quit-at-eof may be abbreviated --quit, but not --qui, since both --quit-at-eof and --quiet begin with --qui. Some long
286 option names are in uppercase, such as --QUIT-AT-EOF, as distinct from --quit-at-eof. Such option names need only have their first letter capitalized; the remainder of the name
287 may be in either case. For example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
288
289 Options are also taken from the environment variable "LESS". For example, to avoid typing "less -options ..." each time less is invoked, you might tell csh:
290
291 setenv LESS "-options"
292
293 or if you use sh:
294
295 LESS="-options"; export LESS
296
297 On MS-DOS, you don't need the quotes, but you should replace any percent signs in the options string by double percent signs.
298
299 The environment variable is parsed before the command line, so command line options override the LESS environment variable. If an option appears in the LESS variable, it can be
300 reset to its default value on the command line by beginning the command line option with "-+".
301
302 Some options like -k or -D require a string to follow the option letter. The string for that option is considered to end when a dollar sign ($) is found. For example, you can
303 set two -D options on MS-DOS like this:
304
305 LESS="Dn9.1$Ds4.1"
306
307 If the --use-backslash option appears earlier in the options, then a dollar sign or backslash may be included literally in an option string by preceding it with a backslash. If
308 the --use-backslash option is not in effect, then backslashes are not treated specially, and there is no way to include a dollar sign in the option string.
309
310 -? or --help
311 This option displays a summary of the commands accepted by less (the same as the h command). (Depending on how your shell interprets the question mark, it may be necessary
312 to quote the question mark, thus: "-\?".)
313
314 -a or --search-skip-screen
315 By default, forward searches start at the top of the displayed screen and backwards searches start at the bottom of the displayed screen (except for repeated searches
316 invoked by the n or N commands, which start after or before the "target" line respectively; see the -j option for more about the target line). The -a option causes forward
317 searches to instead start at the bottom of the screen and backward searches to start at the top of the screen, thus skipping all lines displayed on the screen.
318
319 -A or --SEARCH-SKIP-SCREEN
320 Causes all forward searches (not just non-repeated searches) to start just after the target line, and all backward searches to start just before the target line. Thus,
321 forward searches will skip part of the displayed screen (from the first line up to and including the target line). Similarly backwards searches will skip the displayed
322 screen from the last line up to and including the target line. This was the default behavior in less versions prior to 441.
323
324 -bn or --buffers=n
325 Specifies the amount of buffer space less will use for each file, in units of kilobytes (1024 bytes). By default 64 K of buffer space is used for each file (unless the
326 file is a pipe; see the -B option). The -b option specifies instead that n kilobytes of buffer space should be used for each file. If n is -1, buffer space is unlimited;
327 that is, the entire file can be read into memory.
328
329 -B or --auto-buffers
330 By default, when data is read from a pipe, buffers are allocated automatically as needed. If a large amount of data is read from the pipe, this can cause a large amount of
331 memory to be allocated. The -B option disables this automatic allocation of buffers for pipes, so that only 64 K (or the amount of space specified by the -b option) is
332 used for the pipe. Warning: use of -B can result in erroneous display, since only the most recently viewed part of the piped data is kept in memory; any earlier data is
333 lost.
334
335 -c or --clear-screen
336 Causes full screen repaints to be painted from the top line down. By default, full screen repaints are done by scrolling from the bottom of the screen.
337
338 -C or --CLEAR-SCREEN
339 Same as -c, for compatibility with older versions of less.
340
341 -d or --dumb
342 The -d option suppresses the error message normally displayed if the terminal is dumb; that is, lacks some important capability, such as the ability to clear the screen or
343 scroll backward. The -d option does not otherwise change the behavior of less on a dumb terminal.
344
345 -Dxcolor or --color=xcolor
346 [MS-DOS only] Sets the color of the text displayed. x is a single character which selects the type of text whose color is being set: n=normal, s=standout, d=bold, u=underâ€
347 lined, k=blink. color is a pair of numbers separated by a period. The first number selects the foreground color and the second selects the background color of the text.
348 A single number N is the same as N.M, where M is the normal background color. The color may start or end with u to use underline (with the normal color, if by itself), if
349 the system supports it (Windows only). x may also be a to toggle strict ANSI sequence rendering (SGR mode).
350
351 -e or --quit-at-eof
352 Causes less to automatically exit the second time it reaches end-of-file. By default, the only way to exit less is via the "q" command.
353
354 -E or --QUIT-AT-EOF
355 Causes less to automatically exit the first time it reaches end-of-file.
356
357 -f or --force
358 Forces non-regular files to be opened. (A non-regular file is a directory or a device special file.) Also suppresses the warning message when a binary file is opened. By
359 default, less will refuse to open non-regular files. Note that some operating systems will not allow directories to be read, even if -f is set.
360
361 -F or --quit-if-one-screen
362 Causes less to automatically exit if the entire file can be displayed on the first screen.
363
364 -g or --hilite-search
365 Normally, less will highlight ALL strings which match the last search command. The -g option changes this behavior to highlight only the particular string which was found
366 by the last search command. This can cause less to run somewhat faster than the default.
367
368 -G or --HILITE-SEARCH
369 The -G option suppresses all highlighting of strings found by search commands.
370
371 -hn or --max-back-scroll=n
372 Specifies a maximum number of lines to scroll backward. If it is necessary to scroll backward more than n lines, the screen is repainted in a forward direction instead.
373 (If the terminal does not have the ability to scroll backward, -h0 is implied.)
374
375 -i or --ignore-case
376 Causes searches to ignore case; that is, uppercase and lowercase are considered identical. This option is ignored if any uppercase letters appear in the search pattern; in
377 other words, if a pattern contains uppercase letters, then that search does not ignore case.
378
379 -I or --IGNORE-CASE
380 Like -i, but searches ignore case even if the pattern contains uppercase letters.
381
382 -jn or --jump-target=n
383 Specifies a line on the screen where the "target" line is to be positioned. The target line is the line specified by any command to search for a pattern, jump to a line
384 number, jump to a file percentage or jump to a tag. The screen line may be specified by a number: the top line on the screen is 1, the next is 2, and so on. The number
385 may be negative to specify a line relative to the bottom of the screen: the bottom line on the screen is -1, the second to the bottom is -2, and so on. Alternately, the
386 screen line may be specified as a fraction of the height of the screen, starting with a decimal point: .5 is in the middle of the screen, .3 is three tenths down from the
387 first line, and so on. If the line is specified as a fraction, the actual line number is recalculated if the terminal window is resized, so that the target line remains at
388 the specified fraction of the screen height. If any form of the -j option is used, repeated forward searches (invoked with "n" or "N") begin at the line immediately after
389 the target line, and repeated backward searches begin at the target line, unless changed by -a or -A. For example, if "-j4" is used, the target line is the fourth line on
390 the screen, so forward searches begin at the fifth line on the screen. However nonrepeated searches (invoked with "/" or "?") always begin at the start or end of the curâ€
391 rent screen respectively.
392
393 -J or --status-column
394 Displays a status column at the left edge of the screen. The status column shows the lines that matched the current search, and any lines that are marked (via the m or M
395 command). The status column is also used if the -w or -W option is in effect.
396
397 -kfilename or --lesskey-file=filename
398 Causes less to open and interpret the named file as a lesskey (1) file. Multiple -k options may be specified. If the LESSKEY or LESSKEY_SYSTEM environment variable is
399 set, or if a lesskey file is found in a standard place (see KEY BINDINGS), it is also used as a lesskey file.
400
401 -K or --quit-on-intr
402 Causes less to exit immediately (with status 2) when an interrupt character (usually ^C) is typed. Normally, an interrupt character causes less to stop whatever it is
403 doing and return to its command prompt. Note that use of this option makes it impossible to return to the command prompt from the "F" command.
404
405 -L or --no-lessopen
406 Ignore the LESSOPEN environment variable (see the INPUT PREPROCESSOR section below). This option can be set from within less, but it will apply only to files opened subseâ€
407 quently, not to the file which is currently open.
408
409 -m or --long-prompt
410 Causes less to prompt verbosely (like more), with the percent into the file. By default, less prompts with a colon.
411
412 -M or --LONG-PROMPT
413 Causes less to prompt even more verbosely than more.
414
415 -n or --line-numbers
416 Suppresses line numbers. The default (to use line numbers) may cause less to run more slowly in some cases, especially with a very large input file. Suppressing line numâ€
417 bers with the -n option will avoid this problem. Using line numbers means: the line number will be displayed in the verbose prompt and in the = command, and the v command
418 will pass the current line number to the editor (see also the discussion of LESSEDIT in PROMPTS below).
419
420 -N or --LINE-NUMBERS
421 Causes a line number to be displayed at the beginning of each line in the display.
422
423 -ofilename or --log-file=filename
424 Causes less to copy its input to the named file as it is being viewed. This applies only when the input file is a pipe, not an ordinary file. If the file already exists,
425 less will ask for confirmation before overwriting it.
426
427 -Ofilename or --LOG-FILE=filename
428 The -O option is like -o, but it will overwrite an existing file without asking for confirmation.
429
430 If no log file has been specified, the -o and -O options can be used from within less to specify a log file. Without a file name, they will simply report the name of the
431 log file. The "s" command is equivalent to specifying -o from within less.
432
433 -ppattern or --pattern=pattern
434 The -p option on the command line is equivalent to specifying +/pattern; that is, it tells less to start at the first occurrence of pattern in the file.
435
436 -Pprompt or --prompt=prompt
437 Provides a way to tailor the three prompt styles to your own preference. This option would normally be put in the LESS environment variable, rather than being typed in
438 with each less command. Such an option must either be the last option in the LESS variable, or be terminated by a dollar sign.
439 -Ps followed by a string changes the default (short) prompt to that string.
440 -Pm changes the medium (-m) prompt.
441 -PM changes the long (-M) prompt.
442 -Ph changes the prompt for the help screen.
443 -P= changes the message printed by the = command.
444 -Pw changes the message printed while waiting for data (in the F command).
445
446 All prompt strings consist of a sequence of letters and special escape sequences. See the section on PROMPTS for more details.
447
448 -q or --quiet or --silent
449 Causes moderately "quiet" operation: the terminal bell is not rung if an attempt is made to scroll past the end of the file or before the beginning of the file. If the
450 terminal has a "visual bell", it is used instead. The bell will be rung on certain other errors, such as typing an invalid character. The default is to ring the terminal
451 bell in all such cases.
452
453 -Q or --QUIET or --SILENT
454 Causes totally "quiet" operation: the terminal bell is never rung.
455
456 -r or --raw-control-chars
457 Causes "raw" control characters to be displayed. The default is to display control characters using the caret notation; for example, a control-A (octal 001) is displayed
458 as "^A". Warning: when the -r option is used, less cannot keep track of the actual appearance of the screen (since this depends on how the screen responds to each type of
459 control character). Thus, various display problems may result, such as long lines being split in the wrong place.
460
461 -R or --RAW-CONTROL-CHARS
462 Like -r, but only ANSI "color" escape sequences are output in "raw" form. Unlike -r, the screen appearance is maintained correctly in most cases. ANSI "color" escape
463 sequences are sequences of the form:
464
465 ESC [ ... m
466
467 where the "..." is zero or more color specification characters For the purpose of keeping track of screen appearance, ANSI color escape sequences are assumed to not move
468 the cursor. You can make less think that characters other than "m" can end ANSI color escape sequences by setting the environment variable LESSANSIENDCHARS to the list of
469 characters which can end a color escape sequence. And you can make less think that characters other than the standard ones may appear between the ESC and the m by setting
470 the environment variable LESSANSIMIDCHARS to the list of characters which can appear.
471
472 -s or --squeeze-blank-lines
473 Causes consecutive blank lines to be squeezed into a single blank line. This is useful when viewing nroff output.
474
475 -S or --chop-long-lines
476 Causes lines longer than the screen width to be chopped (truncated) rather than wrapped. That is, the portion of a long line that does not fit in the screen width is not
477 shown. The default is to wrap long lines; that is, display the remainder on the next line.
478
479 -ttag or --tag=tag
480 The -t option, followed immediately by a TAG, will edit the file containing that tag. For this to work, tag information must be available; for example, there may be a file
481 in the current directory called "tags", which was previously built by ctags (1) or an equivalent command. If the environment variable LESSGLOBALTAGS is set, it is taken to
482 be the name of a command compatible with global (1), and that command is executed to find the tag. (See http://www.gnu.org/software/global/global.html). The -t option may
483 also be specified from within less (using the - command) as a way of examining a new file. The command ":t" is equivalent to specifying -t from within less.
484
485 -Ttagsfile or --tag-file=tagsfile
486 Specifies a tags file to be used instead of "tags".
487
488 -u or --underline-special
489 Causes backspaces and carriage returns to be treated as printable characters; that is, they are sent to the terminal when they appear in the input.
490
491 -U or --UNDERLINE-SPECIAL
492 Causes backspaces, tabs, carriage returns and "formatting characters" (as defined by Unicode) to be treated as control characters; that is, they are handled as specified by
493 the -r option.
494
495 By default, if neither -u nor -U is given, backspaces which appear adjacent to an underscore character are treated specially: the underlined text is displayed using the
496 terminal's hardware underlining capability. Also, backspaces which appear between two identical characters are treated specially: the overstruck text is printed using the
497 terminal's hardware boldface capability. Other backspaces are deleted, along with the preceding character. Carriage returns immediately followed by a newline are deleted.
498 Other carriage returns are handled as specified by the -r option. Text which is overstruck or underlined can be searched for if neither -u nor -U is in effect.
499
500 -V or --version
501 Displays the version number of less.
502
503 -w or --hilite-unread
504 Temporarily highlights the first "new" line after a forward movement of a full page. The first "new" line is the line immediately following the line previously at the botâ€
505 tom of the screen. Also highlights the target line after a g or p command. The highlight is removed at the next command which causes movement. The entire line is highâ€
506 lighted, unless the -J option is in effect, in which case only the status column is highlighted.
507
508 -W or --HILITE-UNREAD
509 Like -w, but temporarily highlights the first new line after any forward movement command larger than one line.
510
511 -xn,... or --tabs=n,...
512 Sets tab stops. If only one n is specified, tab stops are set at multiples of n. If multiple values separated by commas are specified, tab stops are set at those posiâ€
513 tions, and then continue with the same spacing as the last two. For example, -x9,17 will set tabs at positions 9, 17, 25, 33, etc. The default for n is 8.
514
515 -X or --no-init
516 Disables sending the termcap initialization and deinitialization strings to the terminal. This is sometimes desirable if the deinitialization string does something unnecâ€
517 essary, like clearing the screen.
518
519 -yn or --max-forw-scroll=n
520 Specifies a maximum number of lines to scroll forward. If it is necessary to scroll forward more than n lines, the screen is repainted instead. The -c or -C option may be
521 used to repaint from the top of the screen if desired. By default, any forward movement causes scrolling.
522
523 -zn or --window=n or -n
524 Changes the default scrolling window size to n lines. The default is one screenful. The z and w commands can also be used to change the window size. The "z" may be omitâ€
525 ted for compatibility with some versions of more. If the number n is negative, it indicates n lines less than the current screen size. For example, if the screen is 24
526 lines, -z-4 sets the scrolling window to 20 lines. If the screen is resized to 40 lines, the scrolling window automatically changes to 36 lines.
527
528 -"cc or --quotes=cc
529 Changes the filename quoting character. This may be necessary if you are trying to name a file which contains both spaces and quote characters. Followed by a single charâ€
530 acter, this changes the quote character to that character. Filenames containing a space should then be surrounded by that character rather than by double quotes. Followed
531 by two characters, changes the open quote to the first character, and the close quote to the second character. Filenames containing a space should then be preceded by the
532 open quote character and followed by the close quote character. Note that even after the quote characters are changed, this option remains -" (a dash followed by a double
533 quote).
534
535 -~ or --tilde
536 Normally lines after end of file are displayed as a single tilde (~). This option causes lines after end of file to be displayed as blank lines.
537
538 -# or --shift
539 Specifies the default number of positions to scroll horizontally in the RIGHTARROW and LEFTARROW commands. If the number specified is zero, it sets the default number of
540 positions to one half of the screen width. Alternately, the number may be specified as a fraction of the width of the screen, starting with a decimal point: .5 is half of
541 the screen width, .3 is three tenths of the screen width, and so on. If the number is specified as a fraction, the actual number of scroll positions is recalculated if the
542 terminal window is resized, so that the actual scroll remains at the specified fraction of the screen width.
543
544 --follow-name
545 Normally, if the input file is renamed while an F command is executing, less will continue to display the contents of the original file despite its name change. If --folâ€
546 low-name is specified, during an F command less will periodically attempt to reopen the file by name. If the reopen succeeds and the file is a different file from the
547 original (which means that a new file has been created with the same name as the original (now renamed) file), less will display the contents of that new file.
548
549 --no-keypad
550 Disables sending the keypad initialization and deinitialization strings to the terminal. This is sometimes useful if the keypad strings make the numeric keypad behave in
551 an undesirable manner.
552
553 --use-backslash
554 This option changes the interpretations of options which follow this one. After the --use-backslash option, any backslash in an option string is removed and the following
555 character is taken literally. This allows a dollar sign to be included in option strings.
556
557 --rscroll
558 This option changes the character used to mark truncated lines. It may begin with a two-character attribute indicator like LESSBINFMT does. If there is no attribute indiâ€
559 cator, standout is used. If set to "-", truncated lines are not marked.
560
561 -- A command line argument of "--" marks the end of option arguments. Any arguments following this are interpreted as filenames. This can be useful when viewing a file whose
562 name begins with a "-" or "+".
563
564 + If a command line option begins with +, the remainder of that option is taken to be an initial command to less. For example, +G tells less to start at the end of the file
565 rather than the beginning, and +/xyz tells it to start at the first occurrence of "xyz" in the file. As a special case, +<number> acts like +<number>g; that is, it starts
566 the display at the specified line number (however, see the caveat under the "g" command above). If the option starts with ++, the initial command applies to every file
567 being viewed, not just the first one. The + command described previously may also be used to set (or change) an initial command for every file.
568
569LINE EDITING
570 When entering command line at the bottom of the screen (for example, a filename for the :e command, or the pattern for a search command), certain keys can be used to manipulate
571 the command line. Most commands have an alternate form in [ brackets ] which can be used if a key does not exist on a particular keyboard. (Note that the forms beginning with
572 ESC do not work in some MS-DOS and Windows systems because ESC is the line erase character.) Any of these special keys may be entered literally by preceding it with the "literal"
573 character, either ^V or ^A. A backslash itself may also be entered literally by entering two backslashes.
574
575 LEFTARROW [ ESC-h ]
576 Move the cursor one space to the left.
577
578 RIGHTARROW [ ESC-l ]
579 Move the cursor one space to the right.
580
581 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
582 (That is, CONTROL and LEFTARROW simultaneously.) Move the cursor one word to the left.
583
584 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
585 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cursor one word to the right.
586
587 HOME [ ESC-0 ]
588 Move the cursor to the beginning of the line.
589
590 END [ ESC-$ ]
591 Move the cursor to the end of the line.
592
593 BACKSPACE
594 Delete the character to the left of the cursor, or cancel the command if the command line is empty.
595
596 DELETE or [ ESC-x ]
597 Delete the character under the cursor.
598
599 ^BACKSPACE [ ESC-BACKSPACE ]
600 (That is, CONTROL and BACKSPACE simultaneously.) Delete the word to the left of the cursor.
601
602 ^DELETE [ ESC-X or ESC-DELETE ]
603 (That is, CONTROL and DELETE simultaneously.) Delete the word under the cursor.
604
605 UPARROW [ ESC-k ]
606 Retrieve the previous command line. If you first enter some text and then press UPARROW, it will retrieve the previous command which begins with that text.
607
608 DOWNARROW [ ESC-j ]
609 Retrieve the next command line. If you first enter some text and then press DOWNARROW, it will retrieve the next command which begins with that text.
610
611 TAB Complete the partial filename to the left of the cursor. If it matches more than one filename, the first match is entered into the command line. Repeated TABs will cycle
612 thru the other matching filenames. If the completed filename is a directory, a "/" is appended to the filename. (On MS-DOS systems, a "\" is appended.) The environment
613 variable LESSSEPARATOR can be used to specify a different character to append to a directory name.
614
615 BACKTAB [ ESC-TAB ]
616 Like, TAB, but cycles in the reverse direction thru the matching filenames.
617
618 ^L Complete the partial filename to the left of the cursor. If it matches more than one filename, all matches are entered into the command line (if they fit).
619
620 ^U (Unix and OS/2) or ESC (MS-DOS)
621 Delete the entire command line, or cancel the command if the command line is empty. If you have changed your line-kill character in Unix to something other than ^U, that
622 character is used instead of ^U.
623
624 ^G Delete the entire command line and return to the main prompt.
625
626KEY BINDINGS
627 You may define your own less commands by using the program lesskey (1) to create a lesskey file. This file specifies a set of command keys and an action associated with each key.
628 You may also use lesskey to change the line-editing keys (see LINE EDITING), and to set environment variables. If the environment variable LESSKEY is set, less uses that as the
629 name of the lesskey file. Otherwise, less looks in a standard place for the lesskey file: On Unix systems, less looks for a lesskey file called "$HOME/.less". On MS-DOS and Winâ€
630 dows systems, less looks for a lesskey file called "$HOME/_less", and if it is not found there, then looks for a lesskey file called "_less" in any directory specified in the PATH
631 environment variable. On OS/2 systems, less looks for a lesskey file called "$HOME/less.ini", and if it is not found, then looks for a lesskey file called "less.ini" in any
632 directory specified in the INIT environment variable, and if it not found there, then looks for a lesskey file called "less.ini" in any directory specified in the PATH environment
633 variable. See the lesskey manual page for more details.
634
635 A system-wide lesskey file may also be set up to provide key bindings. If a key is defined in both a local lesskey file and in the system-wide file, key bindings in the local
636 file take precedence over those in the system-wide file. If the environment variable LESSKEY_SYSTEM is set, less uses that as the name of the system-wide lesskey file. Otherâ€
637 wise, less looks in a standard place for the system-wide lesskey file: On Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. (However, if less was built with a
638 different sysconf directory than /usr/local/etc, that directory is where the sysless file is found.) On MS-DOS and Windows systems, the system-wide lesskey file is c:\_sysless.
639 On OS/2 systems, the system-wide lesskey file is c:\sysless.ini.
640
641INPUT PREPROCESSOR
642 You may define an "input preprocessor" for less. Before less opens a file, it first gives your input preprocessor a chance to modify the way the contents of the file are disâ€
643 played. An input preprocessor is simply an executable program (or shell script), which writes the contents of the file to a different file, called the replacement file. The conâ€
644 tents of the replacement file are then displayed in place of the contents of the original file. However, it will appear to the user as if the original file is opened; that is,
645 less will display the original filename as the name of the current file.
646
647 An input preprocessor receives one command line argument, the original filename, as entered by the user. It should create the replacement file, and when finished, print the name
648 of the replacement file to its standard output. If the input preprocessor does not output a replacement filename, less uses the original file, as normal. The input preprocessor
649 is not called when viewing standard input. To set up an input preprocessor, set the LESSOPEN environment variable to a command line which will invoke your input preprocessor.
650 This command line should include one occurrence of the string "%s", which will be replaced by the filename when the input preprocessor command is invoked.
651
652 When less closes a file opened in such a way, it will call another program, called the input postprocessor, which may perform any desired clean-up action (such as deleting the
653 replacement file created by LESSOPEN). This program receives two command line arguments, the original filename as entered by the user, and the name of the replacement file. To
654 set up an input postprocessor, set the LESSCLOSE environment variable to a command line which will invoke your input postprocessor. It may include two occurrences of the string
655 "%s"; the first is replaced with the original name of the file and the second with the name of the replacement file, which was output by LESSOPEN.
656
657 For example, on many Unix systems, these two scripts will allow you to keep files in compressed format, but still let less view them directly:
658
659 lessopen.sh:
660 #! /bin/sh
661 case "$1" in
662 *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
663 if [ -s /tmp/less.$$ ]; then
664 echo /tmp/less.$$
665 else
666 rm -f /tmp/less.$$
667 fi
668 ;;
669 esac
670
671 lessclose.sh:
672 #! /bin/sh
673 rm $2
674
675 To use these scripts, put them both where they can be executed and set LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More complex LESSOPEN and LESSCLOSE scripts
676 may be written to accept other types of compressed files, and so on.
677
678 It is also possible to set up an input preprocessor to pipe the file data directly to less, rather than putting the data into a replacement file. This avoids the need to decomâ€
679 press the entire file before starting to view it. An input preprocessor that works this way is called an input pipe. An input pipe, instead of writing the name of a replacement
680 file on its standard output, writes the entire contents of the replacement file on its standard output. If the input pipe does not write any characters on its standard output,
681 then there is no replacement file and less uses the original file, as normal. To use an input pipe, make the first character in the LESSOPEN environment variable a vertical bar
682 (|) to signify that the input preprocessor is an input pipe.
683
684 For example, on many Unix systems, this script will work like the previous example scripts:
685
686 lesspipe.sh:
687 #! /bin/sh
688 case "$1" in
689 *.Z) uncompress -c $1 2>/dev/null
690 *) exit 1
691 ;;
692 esac
693 exit $?
694
695 To use this script, put it where it can be executed and set LESSOPEN="|lesspipe.sh %s".
696
697 Note that a preprocessor cannot output an empty file, since that is interpreted as meaning there is no replacement, and the original file is used. To avoid this, if LESSOPEN
698 starts with two vertical bars, the exit status of the script becomes meaningful. If the exit status is zero, the output is considered to be replacement text, even if it is empty.
699 If the exit status is nonzero, any output is ignored and the original file is used. For compatibility with previous versions of less, if LESSOPEN starts with only one vertical
700 bar, the exit status of the preprocessor is ignored.
701
702 When an input pipe is used, a LESSCLOSE postprocessor can be used, but it is usually not necessary since there is no replacement file to clean up. In this case, the replacement
703 file name passed to the LESSCLOSE postprocessor is "-".
704
705 For compatibility with previous versions of less, the input preprocessor or pipe is not used if less is viewing standard input. However, if the first character of LESSOPEN is a
706 dash (-), the input preprocessor is used on standard input as well as other files. In this case, the dash is not considered to be part of the preprocessor command. If standard
707 input is being viewed, the input preprocessor is passed a file name consisting of a single dash. Similarly, if the first two characters of LESSOPEN are vertical bar and dash (|-)
708 or two vertical bars and a dash (||-), the input pipe is used on standard input as well as other files. Again, in this case the dash is not considered to be part of the input
709 pipe command.
710
711NATIONAL CHARACTER SETS
712 There are three types of characters in the input file:
713
714 normal characters
715 can be displayed directly to the screen.
716
717 control characters
718 should not be displayed directly, but are expected to be found in ordinary text files (such as backspace and tab).
719
720 binary characters
721 should not be displayed directly and are not expected to be found in text files.
722
723 A "character set" is simply a description of which characters are to be considered normal, control, and binary. The LESSCHARSET environment variable may be used to select a charâ€
724 acter set. Possible values for LESSCHARSET are:
725
726 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars with values between 32 and 126 are normal, and all others are binary.
727
728 iso8859
729 Selects an ISO 8859 character set. This is the same as ASCII, except characters between 160 and 255 are treated as normal characters.
730
731 latin1 Same as iso8859.
732
733 latin9 Same as iso8859.
734
735 dos Selects a character set appropriate for MS-DOS.
736
737 ebcdic Selects an EBCDIC character set.
738
739 IBM-1047
740 Selects an EBCDIC character set used by OS/390 Unix Services. This is the EBCDIC analogue of latin1. You get similar results by setting either LESSCHARSET=IBM-1047 or
741 LC_CTYPE=en_US in your environment.
742
743 koi8-r Selects a Russian character set.
744
745 next Selects a character set appropriate for NeXT computers.
746
747 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. UTF-8 is special in that it supports multi-byte characters in the input file. It is the only character set that
748 supports multi-byte characters.
749
750 windows
751 Selects a character set appropriate for Microsoft Windows (cp 1251).
752
753 In rare cases, it may be desired to tailor less to use a character set other than the ones definable by LESSCHARSET. In this case, the environment variable LESSCHARDEF can be
754 used to define a character set. It should be set to a string where each character in the string represents one character in the character set. The character "." is used for a
755 normal character, "c" for control, and "b" for binary. A decimal number may be used for repetition. For example, "bccc4b." would mean character 0 is binary, 1, 2 and 3 are conâ€
756 trol, 4, 5, 6 and 7 are binary, and 8 is normal. All characters after the last are taken to be the same as the last, so characters 9 through 255 would be normal. (This is an
757 example, and does not necessarily represent any real character set.)
758
759 This table shows the value of LESSCHARDEF which is equivalent to each of the possible values for LESSCHARSET:
760
761 ascii 8bcccbcc18b95.b
762 dos 8bcccbcc12bc5b95.b.
763 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
764 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
765 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
766 191.b
767 iso8859 8bcccbcc18b95.33b.
768 koi8-r 8bcccbcc18b95.b128.
769 latin1 8bcccbcc18b95.33b.
770 next 8bcccbcc18b95.bb125.bb
771
772 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or LANG environment variables, then the
773 default character set is utf-8.
774
775 If that string is not found, but your system supports the setlocale interface, less will use setlocale to determine the character set. setlocale is controlled by setting the LANG
776 or LC_CTYPE environment variables.
777
778 Finally, if the setlocale interface is also not available, the default character set is latin1.
779
780 Control and binary characters are displayed in standout (reverse video). Each such character is displayed in caret notation if possible (e.g. ^A for control-A). Caret notation
781 is used only if inverting the 0100 bit results in a normal printable character. Otherwise, the character is displayed as a hex number in angle brackets. This format can be
782 changed by setting the LESSBINFMT environment variable. LESSBINFMT may begin with a "*" and one character to select the display attribute: "*k" is blinking, "*d" is bold, "*u" is
783 underlined, "*s" is standout, and "*n" is normal. If LESSBINFMT does not begin with a "*", normal attribute is assumed. The remainder of LESSBINFMT is a string which may include
784 one printf-style escape sequence (a % followed by x, X, o, d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters are displayed in underlined hexadecimal surrounded
785 by brackets. The default if no LESSBINFMT is specified is "*s<%02X>". Warning: the result of expanding the character via LESSBINFMT must be less than 31 characters.
786
787 When the character set is utf-8, the LESSUTFBINFMT environment variable acts similarly to LESSBINFMT but it applies to Unicode code points that were successfully decoded but are
788 unsuitable for display (e.g., unassigned code points). Its default value is "<U+%04lX>". Note that LESSUTFBINFMT and LESSBINFMT share their display attribute setting ("*x") so
789 specifying one will affect both; LESSUTFBINFMT is read after LESSBINFMT so its setting, if any, will have priority. Problematic octets in a UTF-8 file (octets of a truncated
790 sequence, octets of a complete but non-shortest form sequence, illegal octets, and stray trailing octets) are displayed individually using LESSBINFMT so as to facilitate diagnosâ€
791 tic of how the UTF-8 file is ill-formed.
792
793PROMPTS
794 The -P option allows you to tailor the prompt to your preference. The string given to the -P option replaces the specified prompt string. Certain characters in the string are
795 interpreted specially. The prompt mechanism is rather complicated to provide flexibility, but the ordinary user need not understand the details of constructing personalized
796 prompt strings.
797
798 A percent sign followed by a single character is expanded according to what the following character is:
799
800 %bX Replaced by the byte offset into the current input file. The b is followed by a single character (shown as X above) which specifies the line whose byte offset is to be
801 used. If the character is a "t", the byte offset of the top line in the display is used, an "m" means use the middle line, a "b" means use the bottom line, a "B" means use
802 the line just after the bottom line, and a "j" means use the "target" line, as specified by the -j option.
803
804 %B Replaced by the size of the current input file.
805
806 %c Replaced by the column number of the text appearing in the first column of the screen.
807
808 %dX Replaced by the page number of a line in the input file. The line to be used is determined by the X, as with the %b option.
809
810 %D Replaced by the number of pages in the input file, or equivalently, the page number of the last line in the input file.
811
812 %E Replaced by the name of the editor (from the VISUAL environment variable, or the EDITOR environment variable if VISUAL is not defined). See the discussion of the LESSEDIT
813 feature below.
814
815 %f Replaced by the name of the current input file.
816
817 %F Replaced by the last component of the name of the current input file.
818
819 %i Replaced by the index of the current file in the list of input files.
820
821 %lX Replaced by the line number of a line in the input file. The line to be used is determined by the X, as with the %b option.
822
823 %L Replaced by the line number of the last line in the input file.
824
825 %m Replaced by the total number of input files.
826
827 %pX Replaced by the percent into the current input file, based on byte offsets. The line used is determined by the X as with the %b option.
828
829 %PX Replaced by the percent into the current input file, based on line numbers. The line used is determined by the X as with the %b option.
830
831 %s Same as %B.
832
833 %t Causes any trailing spaces to be removed. Usually used at the end of the string, but may appear anywhere.
834
835 %T Normally expands to the word "file". However if viewing files via a tags list using the -t option, it expands to the word "tag".
836
837 %x Replaced by the name of the next input file in the list.
838
839 If any item is unknown (for example, the file size if input is a pipe), a question mark is printed instead.
840
841 The format of the prompt string can be changed depending on certain conditions. A question mark followed by a single character acts like an "IF": depending on the following charâ€
842 acter, a condition is evaluated. If the condition is true, any characters following the question mark and condition character, up to a period, are included in the prompt. If the
843 condition is false, such characters are not included. A colon appearing between the question mark and the period can be used to establish an "ELSE": any characters between the
844 colon and the period are included in the string if and only if the IF condition is false. Condition characters (which follow a question mark) may be:
845
846 ?a True if any characters have been included in the prompt so far.
847
848 ?bX True if the byte offset of the specified line is known.
849
850 ?B True if the size of current input file is known.
851
852 ?c True if the text is horizontally shifted (%c is not zero).
853
854 ?dX True if the page number of the specified line is known.
855
856 ?e True if at end-of-file.
857
858 ?f True if there is an input filename (that is, if input is not a pipe).
859
860 ?lX True if the line number of the specified line is known.
861
862 ?L True if the line number of the last line in the file is known.
863
864 ?m True if there is more than one input file.
865
866 ?n True if this is the first prompt in a new input file.
867
868 ?pX True if the percent into the current input file, based on byte offsets, of the specified line is known.
869
870 ?PX True if the percent into the current input file, based on line numbers, of the specified line is known.
871
872 ?s Same as "?B".
873
874 ?x True if there is a next input file (that is, if the current input file is not the last one).
875
876 Any characters other than the special ones (question mark, colon, period, percent, and backslash) become literally part of the prompt. Any of the special characters may be
877 included in the prompt literally by preceding it with a backslash.
878
879 Some examples:
880
881 ?f%f:Standard input.
882
883 This prompt prints the filename, if known; otherwise the string "Standard input".
884
885 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
886
887 This prompt would print the filename, if known. The filename is followed by the line number, if known, otherwise the percent if known, otherwise the byte offset if known. Otherâ€
888 wise, a dash is printed. Notice how each question mark has a matching period, and how the % after the %pt is included literally by escaping it with a backslash.
889
890 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x..%t";
891
892 This prints the filename if this is the first prompt in a file, followed by the "file N of N" message if there is more than one input file. Then, if we are at end-of-file, the
893 string "(END)" is printed followed by the name of the next file, if there is one. Finally, any trailing spaces are truncated. This is the default prompt. For reference, here
894 are the defaults for the other two prompts (-m and -M respectively). Each is broken into two lines here for readability only.
895
896 ?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\: %x.:
897 ?pB%pB\%:byte %bB?s/%s...%t
898
899 ?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :
900 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t
901
902 And here is the default message produced by the = command:
903
904 ?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .
905 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
906
907 The prompt expansion features are also used for another purpose: if an environment variable LESSEDIT is defined, it is used as the command to be executed when the v command is
908 invoked. The LESSEDIT string is expanded in the same way as the prompt strings. The default value for LESSEDIT is:
909
910 %E ?lm+%lm. %f
911
912 Note that this expands to the editor name, followed by a + and the line number, followed by the file name. If your editor does not accept the "+linenumber" syntax, or has other
913 differences in invocation syntax, the LESSEDIT variable can be changed to modify this default.
914
915SECURITY
916 When the environment variable LESSSECURE is set to 1, less runs in a "secure" mode. This means these features are disabled:
917
918 ! the shell command
919
920 | the pipe command
921
922 :e the examine command.
923
924 v the editing command
925
926 s -o log files
927
928 -k use of lesskey files
929
930 -t use of tags files
931
932 metacharacters in filenames, such as *
933
934 filename completion (TAB, ^L)
935
936 Less can also be compiled to be permanently in "secure" mode.
937
938COMPATIBILITY WITH MORE
939 If the environment variable LESS_IS_MORE is set to 1, or if the program is invoked via a file link named "more", less behaves (mostly) in conformance with the POSIX "more" command
940 specification. In this mode, less behaves differently in these ways:
941
942 The -e option works differently. If the -e option is not set, less behaves as if the -e option were set. If the -e option is set, less behaves as if the -E option were set.
943
944 The -m option works differently. If the -m option is not set, the medium prompt is used, and it is prefixed with the string "--More--". If the -m option is set, the short prompt
945 is used.
946
947 The -n option acts like the -z option. The normal behavior of the -n option is unavailable in this mode.
948
949 The parameter to the -p option is taken to be a less command rather than a search pattern.
950
951 The LESS environment variable is ignored, and the MORE environment variable is used in its place.
952
953ENVIRONMENT VARIABLES
954 Environment variables may be specified either in the system environment as usual, or in a lesskey (1) file. If environment variables are defined in more than one place, variables
955 defined in a local lesskey file take precedence over variables defined in the system environment, which take precedence over variables defined in the system-wide lesskey file.
956
957 COLUMNS
958 Sets the number of columns on the screen. Takes precedence over the number of columns specified by the TERM variable. (But if you have a windowing system which supports
959 TIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes precedence over the LINES and COLUMNS environment variables.)
960
961 EDITOR The name of the editor (used for the v command).
962
963 HOME Name of the user's home directory (used to find a lesskey file on Unix and OS/2 systems).
964
965 HOMEDRIVE, HOMEPATH
966 Concatenation of the HOMEDRIVE and HOMEPATH environment variables is the name of the user's home directory if the HOME variable is not set (only in the Windows version).
967
968 INIT Name of the user's init directory (used to find a lesskey file on OS/2 systems).
969
970 LANG Language for determining the character set.
971
972 LC_CTYPE
973 Language for determining the character set.
974
975 LESS Options which are passed to less automatically.
976
977 LESSANSIENDCHARS
978 Characters which may end an ANSI color escape sequence (default "m").
979
980 LESSANSIMIDCHARS
981 Characters which may appear between the ESC character and the end character in an ANSI color escape sequence (default "0123456789:;[?!"'#%()*+ ".
982
983 LESSBINFMT
984 Format for displaying non-printable, non-control characters.
985
986 LESSCHARDEF
987 Defines a character set.
988
989 LESSCHARSET
990 Selects a predefined character set.
991
992 LESSCLOSE
993 Command line to invoke the (optional) input-postprocessor.
994
995 LESSECHO
996 Name of the lessecho program (default "lessecho"). The lessecho program is needed to expand metacharacters, such as * and ?, in filenames on Unix systems.
997
998 LESSEDIT
999 Editor prototype string (used for the v command). See discussion under PROMPTS.
1000
1001 LESSGLOBALTAGS
1002 Name of the command used by the -t option to find global tags. Normally should be set to "global" if your system has the global (1) command. If not set, global tags are
1003 not used.
1004
1005 LESSHISTFILE
1006 Name of the history file used to remember search commands and shell commands between invocations of less. If set to "-" or "/dev/null", a history file is not used. The
1007 default is "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini" on OS/2 systems.
1008
1009 LESSHISTSIZE
1010 The maximum number of commands to save in the history file. The default is 100.
1011
1012 LESSKEY
1013 Name of the default lesskey(1) file.
1014
1015 LESSKEY_SYSTEM
1016 Name of the default system-wide lesskey(1) file.
1017
1018 LESSMETACHARS
1019 List of characters which are considered "metacharacters" by the shell.
1020
1021 LESSMETAESCAPE
1022 Prefix which less will add before each metacharacter in a command sent to the shell. If LESSMETAESCAPE is an empty string, commands containing metacharacters will not be
1023 passed to the shell.
1024
1025 LESSOPEN
1026 Command line to invoke the (optional) input-preprocessor.
1027
1028 LESSSECURE
1029 Runs less in "secure" mode. See discussion under SECURITY.
1030
1031 LESSSEPARATOR
1032 String to be appended to a directory name in filename completion.
1033
1034 LESSUTFBINFMT
1035 Format for displaying non-printable Unicode code points.
1036
1037 LESS_IS_MORE
1038 Emulate the more (1) command.
1039
1040 LINES Sets the number of lines on the screen. Takes precedence over the number of lines specified by the TERM variable. (But if you have a windowing system which supports
1041 TIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes precedence over the LINES and COLUMNS environment variables.)
1042
1043 MORE Options which are passed to less automatically when running in more compatible mode.
1044
1045 PATH User's search path (used to find a lesskey file on MS-DOS and OS/2 systems).
1046
1047 SHELL The shell used to execute the ! command, as well as to expand filenames.
1048
1049 TERM The type of terminal on which less is being run.
1050
1051 VISUAL The name of the editor (used for the v command).
1052
1053SEE ALSO
1054 lesskey(1)
1055
1056COPYRIGHT
1057 Copyright (C) 1984-2017 Mark Nudelman
1058
1059 less is part of the GNU project and is free software. You can redistribute it and/or modify it under the terms of either (1) the GNU General Public License as published by the
1060 Free Software Foundation; or (2) the Less License. See the file README in the less distribution for more details regarding redistribution. You should have received a copy of the
1061 GNU General Public License along with the source for less; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA
1062 02111-1307, USA. You should also have received a copy of the Less License; see the file LICENSE.
1063
1064 less is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
1065 the GNU General Public License for more details.
1066
1067AUTHOR
1068 Mark Nudelman
1069 Send bug reports or comments to <bug-less@gnu.org>
1070 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list of known bugs in less.
1071 For more information, see the less homepage at
1072 http://www.greenwoodsoftware.com/less.
1073
1074 Version 529: 13 Nov 2017 LESS(1)