Annotation of src/usr.bin/less/less.1, Revision 1.27
1.27 ! jmc 1: .\" $OpenBSD: less.1,v 1.26 2012/03/27 06:22:45 nicm Exp $
1.1 millert 2: .\"
1.23 shadchin 3: .\" Copyright (C) 1984-2011 Mark Nudelman
1.1 millert 4: .\"
1.5 millert 5: .\" Redistribution and use in source and binary forms, with or without
6: .\" modification, are permitted provided that the following conditions
7: .\" are met:
8: .\" 1. Redistributions of source code must retain the above copyright
9: .\" notice, this list of conditions and the following disclaimer.
10: .\" 2. Redistributions in binary form must reproduce the above copyright
1.7 jmc 11: .\" notice in the documentation and/or other materials provided with
1.5 millert 12: .\" the distribution.
1.1 millert 13: .\"
1.5 millert 14: .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY
15: .\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
1.7 jmc 16: .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
1.5 millert 17: .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
1.7 jmc 18: .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
19: .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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21: .\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22: .\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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1.5 millert 24: .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
1.1 millert 25: .\"
1.27 ! jmc 26: .Dd $Mdocdate: March 27 2012 $
1.1 millert 27: .Dt LESS 1
28: .Os
29: .Sh NAME
30: .Nm less , more
1.11 jmc 31: .Nd view files
1.1 millert 32: .Sh SYNOPSIS
1.18 jmc 33: .Nm less \*(Ba more
1.6 jmc 34: .Fl \&?
1.18 jmc 35: .Nm less \*(Ba more
1.1 millert 36: .Fl -help
1.18 jmc 37: .Nm less \*(Ba more
1.1 millert 38: .Fl V
1.18 jmc 39: .Nm less \*(Ba more
1.1 millert 40: .Fl -version
1.18 jmc 41: .Nm less \*(Ba more
1.1 millert 42: .Bk -words
1.24 jmc 43: .Op Fl Oo Cm + Oc Ns Cm AaBCcdEeFfGgIiJKLMmNnQqRrSsUuVWwX~
1.1 millert 44: .Op Fl b Ar space
45: .Op Fl h Ar lines
46: .Op Fl j Ar line
47: .Op Fl k Ar keyfile
1.12 jmc 48: .Op Fl O | o Ar logfile
49: .Op Fl P Ar prompt
1.1 millert 50: .Op Fl p Ar pattern
1.12 jmc 51: .Op Fl T Ar tagsfile
1.1 millert 52: .Op Fl t Ar tag
53: .Op Fl x Ar tab,...
54: .Op Fl y Ar lines
1.18 jmc 55: .Op Fl Oo Cm z Oc Ar lines
1.1 millert 56: .Op Fl # Ar shift
1.18 jmc 57: .Xo Oo Cm \&+ Ns Oo Ns Cm \&+ Ns
1.1 millert 58: .Oc Ar cmd
59: .Oc
60: .Xc
61: .Op Fl -
62: .Op Ar filename ...
63: .Ek
64: .\" (See the
65: .\" .Sx OPTIONS
66: .\" section for alternate option syntax with long option names.)
67: .Sh DESCRIPTION
68: .Nm
69: is a program similar to the traditional
70: .Xr more 1 ,
71: but which allows backward movement in the file as well as forward movement.
72: Also,
73: .Nm
74: does not have to read the entire input file before starting,
75: so with large input files it starts up faster than text editors like
76: .Xr vi 1 .
77: .Nm
78: uses termcap (or terminfo on some systems),
79: so it can run on a variety of terminals.
80: There is even limited support for hardcopy terminals.
81: (On a hardcopy terminal, lines which should be printed at the top
82: of the screen are prefixed with a caret.)
83: .Pp
84: This version of
85: .Nm
86: also acts as
87: .Xr more 1
88: if it is called as
89: .Nm more .
90: In this mode, the differences are in the prompt and that
91: .Nm more
92: exits by default when it gets to the end of the file.
93: Commands are based on both traditional
94: .Nm more
95: and
96: .Xr vi 1 .
97: Commands may be preceded by a decimal number,
98: called N in the descriptions below.
99: The number is used by some commands, as indicated.
100: .Sh COMMANDS
101: In the following descriptions, ^X means control-X.
102: ESC stands for the ESCAPE key; for example ESC-v means the
103: two character sequence "ESCAPE", then "v".
104: .Bl -tag -width XXXX
105: .It Ic h | H
106: Help: display a summary of these commands.
107: If you forget all the other commands, remember this one.
108: .It Ic SPACE | ^V | f | ^F
109: Scroll forward N lines, default one window (see option -z below).
110: If N is more than the screen size, only the final screenful is displayed.
111: Warning: some systems use ^V as a special literalization character.
112: .It Ic z
113: Like SPACE, but if N is specified, it becomes the new window size.
114: .It Ic ESC-SPACE
1.23 shadchin 115: Like SPACE, but scrolls a full screenful, even if it reaches
1.1 millert 116: end-of-file in the process.
1.23 shadchin 117: .It Ic ENTER | RETURN | ^N | e | ^E | j | ^J
1.1 millert 118: Scroll forward N lines, default 1.
119: The entire N lines are displayed, even if N is more than the screen size.
120: .It Ic d | ^D
121: Scroll forward N lines, default one half of the screen size.
122: If N is specified, it becomes the new default for subsequent d and u commands.
123: .It Ic b | ^B | ESC-v
124: Scroll backward N lines, default one window (see option -z below).
125: If N is more than the screen size, only the final screenful is displayed.
126: .It Ic w
127: Like ESC-v, but if N is specified, it becomes the new window size.
1.22 jmc 128: .It Ic y | ^Y | ^P | k | ^K
1.1 millert 129: Scroll backward N lines, default 1.
130: The entire N lines are displayed, even if N is more than the screen size.
131: Warning: some systems use ^Y as a special job control character.
132: .It Ic u | ^U
133: Scroll backward N lines, default one half of the screen size.
134: If N is specified, it becomes the new default for subsequent d and u commands.
135: .It Ic ESC-) | RIGHTARROW
136: Scroll horizontally right N characters, default half the screen width
137: (see the -# option).
138: If a number N is specified, it becomes the default for future
139: RIGHTARROW and LEFTARROW commands.
140: While the text is scrolled, it acts as though the -S option (chop lines)
141: were in effect.
142: .It Ic ESC-( | LEFTARROW
143: Scroll horizontally left N
144: characters, default half the screen width (see the -# option).
145: If a number N is specified, it becomes the default for future
146: RIGHTARROW and LEFTARROW commands.
147: .It Ic r | ^R | ^L
148: Repaint the screen.
149: .It Ic R
150: Repaint the screen, discarding any buffered input.
151: Useful if the file is changing while it is being viewed.
152: .It Ic F
153: Scroll forward, and keep trying to read when the end of file is reached.
154: Normally this command would be used when already at the end of the file.
155: It is a way to monitor the tail of a file which is growing
156: while it is being viewed.
157: (The behavior is similar to the "tail -f" command.)
158: .It Ic g | < | ESC-<
159: Go to line N in the file, default 1 (beginning of file).
160: (Warning: this may be slow if N is large.)
161: .It Ic G | > | ESC->
162: Go to line N in the file, default the end of the file.
163: (Warning: this may be slow if N is large,
164: or if N is not specified and standard input, rather than a file,
165: is being read.)
166: .It Ic p | %
167: Go to a position N percent into the file.
1.23 shadchin 168: N should be between 0 and 100, and may contain a decimal point.
169: .It Ic P
170: Go to the line containing byte offset N in the file.
1.1 millert 171: .It Ic {
172: If a left curly bracket appears in the top line displayed
173: on the screen, the { command will go to the matching right curly bracket.
174: The matching right curly bracket is positioned on the bottom
175: line of the screen.
176: If there is more than one left curly bracket on the top line, a number N
177: may be used to specify the N-th bracket on the line.
178: .It Ic }
179: If a right curly bracket appears in the bottom line displayed on the screen,
180: the } command will go to the matching left curly bracket.
181: The matching left curly bracket is positioned on the top
182: line of the screen.
183: If there is more than one right curly bracket on the top line,
184: a number N may be used to specify the N-th bracket on the line.
185: .It Ic \&(
186: Like {, but applies to parentheses rather than curly brackets.
187: .It Ic \&)
188: Like }, but applies to parentheses rather than curly brackets.
189: .It Ic \&[
190: Like {, but applies to square brackets rather than curly brackets.
191: .It Ic \&]
192: Like }, but applies to square brackets rather than curly brackets.
193: .It Ic ESC-^F
194: Followed by two characters, acts like {,
195: but uses the two characters as open and close brackets, respectively.
196: For example, "ESC ^F < >" could be used to
197: go forward to the > which matches the < in the top displayed line.
198: .It Ic ESC-^B
199: Followed by two characters, acts like },
200: but uses the two characters as open and close brackets, respectively.
201: For example, "ESC ^B < >" could be used to
202: go backward to the < which matches the > in the bottom displayed line.
203: .It Ic m
204: Followed by any lowercase letter, marks the current position with that letter.
205: .It Ic '
206: (Single quote.)
207: Followed by any lowercase letter, returns to the position which
208: was previously marked with that letter.
209: Followed by another single quote, returns to the position at
210: which the last "large" movement command was executed.
211: Followed by a ^ or $, jumps to the beginning or end of the file respectively.
212: Marks are preserved when a new file is examined,
213: so the ' command can be used to switch between input files.
214: .It Ic ^X^X
215: Same as single quote.
216: .It Ic /pattern
217: Search forward in the file for the N-th line containing the pattern.
218: N defaults to 1.
219: The pattern is a regular expression, as recognized by
1.23 shadchin 220: the regular expression library supplied by your system.
221: The search starts at the first line displayed
1.1 millert 222: (but see the -a and -j options, which change this).
223: .Pp
224: Certain characters are special if entered at the beginning of the pattern;
225: they modify the type of search rather than become part of the pattern:
226: .Bl -tag -width Ds
1.6 jmc 227: .It Ic ^N | \&!
1.1 millert 228: Search for lines which do NOT match the pattern.
229: .It Ic ^E | *
230: Search multiple files.
231: That is, if the search reaches the END of the current file
232: without finding a match,
233: the search continues in the next file in the command line list.
234: .It Ic ^F | @
235: Begin the search at the first line of the FIRST file
236: in the command line list,
237: regardless of what is currently displayed on the screen
238: or the settings of the -a or -j options.
239: .It Ic ^K
240: Highlight any text which matches the pattern on the current screen,
241: but don't move to the first match (KEEP current position).
242: .It Ic ^R
243: Don't interpret regular expression metacharacters;
244: that is, do a simple textual comparison.
245: .El
246: .It Ic ?pattern
247: Search backward in the file for the N-th line containing the pattern.
248: The search starts at the line immediately before the top line displayed.
249: .Pp
250: Certain characters are special, as in the / command:
251: .Bl -tag -width Ds
1.6 jmc 252: .It Ic ^N | \&!
1.1 millert 253: Search for lines which do NOT match the pattern.
254: .It Ic ^E | *
255: Search multiple files.
256: That is, if the search reaches the beginning of the current file
257: without finding a match,
258: the search continues in the previous file in the command line list.
259: .It Ic ^F | @
260: Begin the search at the last line of the last file
261: in the command line list,
262: regardless of what is currently displayed on the screen
263: or the settings of the -a or -j options.
264: .It Ic ^K
265: As in forward searches.
266: .It Ic ^R
267: As in forward searches.
268: .El
269: .It Ic ESC-/pattern
270: Same as "/*".
271: .It Ic ESC-?pattern
272: Same as "?*".
273: .It Ic n
274: Repeat previous search, for N-th line containing the last pattern.
275: If the previous search was modified by ^N, the search is made for the
276: N-th line NOT containing the pattern.
277: If the previous search was modified by ^E, the search continues
278: in the next (or previous) file if not satisfied in the current file.
279: If the previous search was modified by ^R, the search is done
280: without using regular expressions.
281: There is no effect if the previous search was modified by ^F or ^K.
282: .It Ic N
283: Repeat previous search, but in the reverse direction.
284: .It Ic ESC-n
285: Repeat previous search, but crossing file boundaries.
286: The effect is as if the previous search were modified by *.
287: .It Ic ESC-N
288: Repeat previous search, but in the reverse direction
289: and crossing file boundaries.
290: .It Ic ESC-u
291: Undo search highlighting.
292: Turn off highlighting of strings matching the current search pattern.
293: If highlighting is already off because of a previous ESC-u command,
294: turn highlighting back on.
295: Any search command will also turn highlighting back on.
296: (Highlighting can also be disabled by toggling the -G option;
297: in that case search commands do not turn highlighting back on.)
1.23 shadchin 298: .It Ic &pattern
299: Display only lines which match the pattern;
300: lines which do not match the pattern are not displayed.
301: If pattern is empty (if you type & immediately followed by ENTER),
302: any filtering is turned off, and all lines are displayed.
303: While filtering is in effect, an ampersand is displayed at the
304: beginning of the prompt,
305: as a reminder that some lines in the file may be hidden.
306: .Pp
307: Certain characters are special as in the / command:
308: .Bl -tag -width Ds
309: .It Ic ^N | !
310: Display only lines which do NOT match the pattern.
311: .It Ic ^R
312: Don't interpret regular expression metacharacters;
313: that is, do a simple textual comparison.
314: .El
1.1 millert 315: .It Ic :e Op Ar filename
316: Examine a new file.
317: If the filename is missing, the "current" file (see the :n and :p commands
318: below) from the list of files in the command line is re-examined.
319: A percent sign (%) in the filename is replaced by the name of the
320: current file.
321: A pound sign (#) is replaced by the name of the previously examined file.
322: However, two consecutive percent signs are simply
323: replaced with a single percent sign.
324: This allows you to enter a filename that contains a percent sign
325: in the name.
326: Similarly, two consecutive pound signs are replaced with a single pound sign.
327: The filename is inserted into the command line list of files
328: so that it can be seen by subsequent :n and :p commands.
329: If the filename consists of several files, they are all inserted into
330: the list of files and the first one is examined.
331: If the filename contains one or more spaces,
332: the entire filename should be enclosed in double quotes
333: (also see the -" option).
334: .It Ic ^X^V | E
335: Same as :e.
336: Warning: some systems use ^V as a special literalization character.
337: On such systems, you may not be able to use ^V.
338: .It Ic :n
339: Examine the next file (from the list of files given in the command line).
340: If a number N is specified, the N-th next file is examined.
341: .It Ic :p
342: Examine the previous file in the command line list.
343: If a number N is specified, the N-th previous file is examined.
344: .It Ic :t
345: Go to the specified tag.
346: .It Ic :x
347: Examine the first file in the command line list.
348: If a number N is specified, the N-th file in the list is examined.
349: .It Ic :d
350: Remove the current file from the list of files.
351: .It Ic t
352: Go to the next tag, if there were more than one matches for the current tag.
353: See the \-t option for more details about tags.
354: .It Ic T
355: Go to the previous tag, if there were more than one matches for the current tag.
356: .It Ic = | ^G | :f
357: Prints some information about the file being viewed, including its name
358: and the line number and byte offset of the bottom line being displayed.
359: If possible, it also prints the length of the file,
360: the number of lines in the file
361: and the percent of the file above the last displayed line.
362: .It Ic \-
363: Followed by one of the command line option letters (see
364: .Sx OPTIONS
365: below),
366: this will change the setting of that option
367: and print a message describing the new setting.
368: If a ^P (CONTROL-P) is entered immediately after the dash,
369: the setting of the option is changed but no message is printed.
370: If the option letter has a numeric value (such as -b or -h),
371: or a string value (such as -P or -t),
372: a new value may be entered after the option letter.
373: If no new value is entered, a message describing
374: the current setting is printed and nothing is changed.
375: .It Ic \-\-
376: Like the \- command, but takes a long option name (see
377: .Sx OPTIONS
378: below)
379: rather than a single option letter.
1.23 shadchin 380: You must press ENTER or RETURN after typing the option name.
1.1 millert 381: A ^P immediately after the second dash suppresses printing of a
382: message describing the new setting, as in the \- command.
383: .It Ic \-+
384: Followed by one of the command line option letters this will reset the
385: option to its default setting and print a message describing the new setting.
386: (The "\-+X" command does the same thing as "\-+X" on the command line.)
387: This does not work for string-valued options.
388: .It Ic \-\-+
389: Like the \-+ command, but takes a long option name
390: rather than a single option letter.
391: .It Ic \-!
392: Followed by one of the command line option letters, this will reset the
393: option to the "opposite" of its default setting and print a message
394: describing the new setting.
395: This does not work for numeric or string-valued options.
396: .It Ic \-\-!
397: Like the \-! command, but takes a long option name
398: rather than a single option letter.
399: .It Ic _
400: (Underscore.)
401: Followed by one of the command line option letters,
402: this will print a message describing the current setting of that option.
403: The setting of the option is not changed.
404: .It Ic __
405: (Double underscore.)
406: Like the _ (underscore) command, but takes a long option name
407: rather than a single option letter.
1.23 shadchin 408: You must press ENTER or RETURN after typing the option name.
1.1 millert 409: .It Ic +cmd
410: Causes the specified cmd to be executed each time a new file is examined.
411: For example, +G causes
412: .Nm
413: to initially display each file starting at the end rather than the beginning.
414: .It Ic V
415: Prints the version number of
416: .Nm
417: being run.
1.22 jmc 418: .It Ic q | Q | :q | :Q | ZZ
1.1 millert 419: Exits
420: .Nm less .
421: .El
422: .Pp
423: The following
424: four
425: commands may or may not be valid, depending on your particular installation.
426: .Bl -tag -width XXXX
427: .It Ic v
428: Invokes an editor to edit the current file being viewed.
429: The editor is taken from the environment variable
430: .Ev VISUAL ,
431: if defined,
432: or
433: .Ev EDITOR
434: if
435: .Ev VISUAL
436: is not defined,
437: or defaults to "vi" if neither
438: .Ev VISUAL
439: nor
440: .Ev EDITOR
441: is defined.
442: See also the discussion of LESSEDIT under the section on
443: .Sx PROMPTS
444: below.
1.6 jmc 445: .It Ic \&! Ar shell-command
1.1 millert 446: Invokes a shell to run the shell-command given.
447: A percent sign (%) in the command is replaced by the name of the current file.
448: A pound sign (#) is replaced by the name of the previously examined file.
449: "!!" repeats the last shell command.
450: "!" with no shell command simply invokes a shell.
451: The shell is taken from the environment variable
452: .Ev SHELL ,
453: or defaults to "sh".
454: .\" On MS-DOS and OS/2 systems, the shell is the normal command processor.
1.22 jmc 455: .It Ic | <m> Ar shell-command
1.1 millert 456: <m> represents any mark letter.
457: Pipes a section of the input file to the given shell command.
458: The section of the file to be piped is between the first line on
459: the current screen and the position marked by the letter.
460: <m> may also be ^ or $ to indicate beginning or end of file respectively.
461: If <m> is . or newline, the current screen is piped.
462: .It Ic s Ar filename
463: Save the input to a file.
464: This only works if the input is a pipe, not an ordinary file.
465: .El
466: .Sh OPTIONS
467: Command line options are described below.
468: Most options may be changed while
469: .Nm
470: is running, via the "\-" command.
471: .Pp
472: Most options may be given in one of two forms:
473: either a dash followed by a single letter, or two dashes followed by a
474: long option name.
475: A long option name may be abbreviated as long as the abbreviation is
476: unambiguous.
477: For example, --quit-at-eof may be abbreviated --quit, but not
478: --qui, since both --quit-at-eof and --quiet begin with --qui.
479: Some long option names are in uppercase, such as --QUIT-AT-EOF, as
480: distinct from --quit-at-eof.
481: Such option names need only have their first letter capitalized;
482: the remainder of the name may be in either case.
483: For example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.
484: .Pp
485: Options are also taken from the environment variable
486: .Ev LESS
487: if the command is
488: .Nm less ,
489: or from the environment variable
490: .Ev MORE
491: if the command is
492: .Nm more .
493: For example, to avoid typing "less -options ..." each time
494: .Nm
495: is invoked, you might tell
496: .Xr csh 1 :
497: .Pp
498: .Dl setenv LESS "-options"
499: .Pp
500: or if you use
501: .Xr sh 1 :
502: .Pp
503: .Dl LESS="-options"; export LESS
504: .Pp
505: .\" On MS-DOS, you don't need the quotes, but you should replace any
506: .\" percent signs in the options string by double percent signs.
507: .\" .Pp
508: The environment variable is parsed before the command line,
509: so command line options override the
510: .Ev LESS
511: environment variable.
512: If an option appears in the
513: .Ev LESS
514: variable, it can be reset to its default value on the command line by
515: beginning the command line option with "\-+".
516: .Pp
517: For options like -P which take a following string,
518: a dollar sign ($) must be used to signal the end of the string.
519: For example, to separate a prompt value from any other options
520: with dollar sign between them:
521: .Pp
522: .Dl LESS="-Ps--More--$-C -e"
523: .Bl -tag -width XXXX
1.6 jmc 524: .It Fl \&? | -help
1.1 millert 525: This option displays a summary of the commands accepted by
526: .Nm
527: (the same as the h command).
528: (Depending on how your shell interprets the question mark,
529: it may be necessary to quote the question mark, thus: "-\e?".)
1.23 shadchin 530: .It Fl A | -SEARCH-SKIP-SCREEN
531: Causes all forward searches (not just non-repeated searches)
532: to start just after the target line, and all backward searches
533: to start just before the target line.
534: Thus, forward searches will skip part of the displayed screen
535: (from the first line up to and including the target line).
536: Similarly backwards searches will skip the displayed screen
537: from the last line up to and including the target line.
538: This was the default behavior in less versions prior to 441.
1.1 millert 539: .It Fl a | -search-skip-screen
1.23 shadchin 540: By default, forward searches start at the top of the displayed screen
541: and backwards searches start at the bottom of the displayed screen
542: (except for repeated searches invoked by the n or N commands,
543: which start after or before the "target" line respectively;
544: see the -j option for more about the target line).
545: The -a option causes forward searches to instead start at
546: the bottom of the screen
547: and backward searches to start at the top of the screen,
1.1 millert 548: thus skipping all lines displayed on the screen.
1.12 jmc 549: .It Fl B | -auto-buffers
550: By default, when data is read from a pipe,
551: buffers are allocated automatically as needed.
552: If a large amount of data is read from the pipe, this can cause
553: a large amount of memory to be allocated.
554: The -B option disables this automatic allocation of buffers for pipes,
555: so that only 64K (or the amount of space specified by the -b option)
556: is used for the pipe.
557: Warning: use of -B can result in erroneous display, since only the
1.23 shadchin 558: most recently viewed part of the piped data is kept in memory;
1.12 jmc 559: any earlier data is lost.
1.1 millert 560: .It Xo
561: .Fl b Ns Ar n |
1.8 jmc 562: .Fl -buffers Ns = Ns Ar n
1.1 millert 563: .Xc
564: Specifies the amount of buffer space
565: .Nm
566: will use for each file, in units of kilobytes (1024 bytes).
567: By default 64K of buffer space is used for each file
568: (unless the file is a pipe; see the -B option).
569: The -b option specifies instead that n kilobytes of
570: buffer space should be used for each file.
571: If n is -1, buffer space is unlimited; that is,
1.23 shadchin 572: the entire file can be read into memory.
1.12 jmc 573: .It Fl C | -CLEAR-SCREEN
1.23 shadchin 574: Same as -c, for compatibility with older versions of
575: .Nm less .
1.1 millert 576: .It Fl c | -clear-screen
1.27 ! jmc 577: Causes full screen repaints to be painted from the bottom of the screen.
! 578: By default, full screen repaints are done from the top line down
! 579: to avoid the position of the display being moved
1.26 nicm 580: when using interactive commands.
1.1 millert 581: .It Fl d | -dumb No (less only)
582: The -d option suppresses the error message
583: normally displayed if the terminal is dumb;
584: that is, lacks some important capability,
585: such as the ability to clear the screen or scroll backward.
586: The -d option does not otherwise change the behavior of
587: .Nm
588: on a dumb terminal.
589: This option is on by default when invoked as
590: .Nm more .
591: .It Fl d No (more only)
592: The -d option causes the default prompt to include the
593: basic directions ``[Press space to continue, 'q' to quit.]''.
594: The -d option also causes the message ``[Press 'h' for instructions.]'' to be
595: displayed when an invalid command is entered (normally, the bell is rung).
596: This option is useful in environments where users may not be experienced
597: with pagers.
598: .\" .It Fl Dxcolor or --color=xcolor"
599: .\" [MS-DOS only]
600: .\" Sets the color of the text displayed.
601: .\" x is a single character which selects the type of text whose color is
602: .\" being set: n=normal, s=standout, d=bold, u=underlined, k=blink.
603: .\" color is a pair of numbers separated by a period.
604: .\" The first number selects the foreground color and the second selects
605: .\" the background color of the text.
1.23 shadchin 606: .\" A single number N is the same as N.M,
607: .\" where M is the normal background color.
1.12 jmc 608: .It Fl E | -QUIT-AT-EOF
609: Causes
610: .Nm
611: to automatically exit the first time it reaches end-of-file.
1.1 millert 612: .It Fl e | -quit-at-eof
613: Causes
614: .Nm
615: to automatically exit the second time it reaches end-of-file.
616: By default, the only way to exit
617: .Nm
618: is via the "q" command.
1.12 jmc 619: .It Fl F | -quit-if-one-screen
1.1 millert 620: Causes
621: .Nm
1.12 jmc 622: to automatically exit if the entire file can be displayed on the first screen.
1.1 millert 623: .It Fl f | -force
624: Forces non-regular files to be opened.
625: (A non-regular file is a directory or a device special file.)
626: Also suppresses the warning message when a binary file is opened.
627: By default,
628: .Nm
629: will refuse to open non-regular files.
1.12 jmc 630: .It Fl G | -HILITE-SEARCH
631: The -G option suppresses all highlighting of strings found by search commands.
1.1 millert 632: .It Fl g | -hilite-search
633: Normally,
634: .Nm
635: will highlight ALL strings which match the last search command.
636: The -g option changes this behavior to highlight only the particular string
637: which was found by the last search command.
638: This can cause
639: .Nm
640: to run somewhat faster than the default.
641: .It Xo
642: .Fl h Ns Ar n |
1.8 jmc 643: .Fl -max-back-scroll Ns = Ns Ar n
1.1 millert 644: .Xc
645: Specifies a maximum number of lines to scroll backward.
646: If it is necessary to scroll backward more than n lines,
647: the screen is repainted in a forward direction instead.
648: (If the terminal does not have the ability to scroll backward, -h0 is implied.)
1.12 jmc 649: .It Fl I | -IGNORE-CASE
650: Like -i, but searches ignore case even if the pattern contains uppercase
651: letters.
1.1 millert 652: .It Fl i | -ignore-case
653: Causes searches to ignore case; that is,
654: uppercase and lowercase are considered identical.
655: This option is ignored if any uppercase letters appear in the search pattern;
656: in other words,
657: if a pattern contains uppercase letters, then that search does not ignore case.
1.12 jmc 658: .It Fl J | -status-column
659: Displays a status column at the left edge of the screen.
660: The status column shows the lines that matched the current search.
661: The status column is also used if the -w or -W option is in effect.
1.1 millert 662: .It Xo
663: .Fl j Ns Ar n |
1.8 jmc 664: .Fl -jump-target Ns = Ns Ar n
1.1 millert 665: .Xc
666: Specifies a line on the screen where the "target" line is to be positioned.
1.23 shadchin 667: The target line is the line specified by any command to
668: search for a pattern, jump to a line number,
669: jump to a file percentage or jump to a tag.
670: The screen line may be specified by a number: the top line on the screen
1.1 millert 671: is 1, the next is 2, and so on.
672: The number may be negative to specify a line relative to the bottom
673: of the screen: the bottom line on the screen is -1, the second
674: to the bottom is -2, and so on.
1.23 shadchin 675: Alternately, the screen line may be specified as a fraction of the height
676: of the screen, starting with a decimal point: .5 is in the middle of the
677: screen, .3 is three tenths down from the first line, and so on.
678: If the line is specified as a fraction, the actual line number
679: is recalculated if the terminal window is resized, so that the
680: target line remains at the specified fraction of the screen height.
1.24 jmc 681: If any form of the -j option is used,
1.23 shadchin 682: forward searches begin at the line immediately after the target line,
683: and backward searches begin at the target line,
684: unless changed by -a or -A.
1.1 millert 685: For example, if "-j4" is used, the target line is the
1.23 shadchin 686: fourth line on the screen, so forward searches begin at the fifth line
687: on the screen.
688: .It Fl K | -quit-on-intr
689: Causes
690: .Nm
691: to exit immediately (with status 2)
692: when an interrupt character (usually ^C) is typed.
693: Normally, an interrupt character causes
694: .Nm
695: to stop whatever it is doing and return to its command prompt.
1.24 jmc 696: Note that use of this option makes it impossible to return to the
1.23 shadchin 697: command prompt from the "F" command.
1.1 millert 698: .It Xo
699: .Fl k Ns Ar filename |
1.8 jmc 700: .Fl -lesskey-file Ns = Ns Ar filename
1.1 millert 701: .Xc
702: Causes
703: .Nm
704: to open and interpret the named file as a
705: .Xr lesskey 1
706: file.
707: Multiple -k options may be specified.
708: If the
709: .Ev LESSKEY
710: or
711: .Ev LESSKEY_SYSTEM
712: environment variable is set, or if a lesskey file is found in a standard place
713: (see
714: .Sx KEY BINDINGS ) ,
715: it is also used as a lesskey file.
716: .It Fl L | -no-lessopen
717: Ignore the
718: .Ev LESSOPEN
719: environment variable (see the
720: .Sx INPUT PREPROCESSOR
721: section below).
722: This option can be set from within
723: .Nm less ,
724: but it will apply only to files opened subsequently, not to the
725: file which is currently open.
726: When invoked as
727: .Nm more ,
728: the
729: .Ev LESSOPEN
730: environment variable is ignored by default.
1.12 jmc 731: .It Fl M | -LONG-PROMPT
732: Causes
733: .Nm
734: to prompt even more verbosely than
735: .Nm more .
1.1 millert 736: .It Fl m | -long-prompt
737: Causes
738: .Nm
739: to prompt verbosely (like more), with the percent into the file.
740: By default,
741: .Nm
742: prompts with a colon.
1.12 jmc 743: .It Fl N | -LINE-NUMBERS
744: Causes a line number to be displayed at the beginning of each line in the
745: display.
1.1 millert 746: .It Fl n | -line-numbers
747: Suppresses line numbers.
748: The default (to use line numbers) may cause
749: .Nm
750: to run more slowly in some cases, especially with a very large input file.
751: Suppressing line numbers with the -n option will avoid this problem.
752: Using line numbers means: the line number will be displayed in the verbose
753: prompt and in the = command, and the v command will pass the current line
754: number to the editor (see also the discussion of LESSEDIT in
755: .Sx PROMPTS
756: below).
757: .It Xo
758: .Fl O Ns Ar filename |
1.8 jmc 759: .Fl -LOG-FILE Ns = Ns Ar filename
1.1 millert 760: .Xc
761: The -O option is like -o, but it will overwrite an existing
762: file without asking for confirmation.
763: .Pp
764: If no log file has been specified,
765: the -o and -O options can be used from within
766: .Nm
767: to specify a log file.
768: Without a file name, they will simply report the name of the log file.
769: The "s" command is equivalent to specifying -o from within
770: .Nm less .
771: .It Xo
1.12 jmc 772: .Fl o Ns Ar filename |
773: .Fl -log-file Ns = Ns Ar filename
1.1 millert 774: .Xc
1.12 jmc 775: Causes
776: .Nm
777: to copy its input to the named file as it is being viewed.
778: This applies only when the input file is a pipe, not an ordinary file.
779: If the file already exists,
1.1 millert 780: .Nm
1.12 jmc 781: will ask for confirmation before overwriting it.
1.1 millert 782: .It Xo
783: .Fl P Ns Ar prompt |
1.8 jmc 784: .Fl -prompt Ns = Ns Ar prompt
1.1 millert 785: .Xc
786: Provides a way to tailor the three prompt styles to your own preference.
787: This option would normally be put in the
788: .Ev LESS
789: environment variable, rather than being typed in with each
790: .Nm
791: command.
792: Such an option must either be the last option in the
793: .Ev LESS
794: variable, or be terminated by a dollar sign.
795: -Ps followed by a string changes the default (short) prompt to that string.
796: -Pm changes the medium (-m) prompt.
797: -PM changes the long (-M) prompt.
798: -Ph changes the prompt for the help screen.
799: -P= changes the message printed by the = command.
800: -Pw changes the message printed while waiting for data (in the F command).
801: All prompt strings consist of a sequence of letters and special escape
802: sequences.
803: See the section on
804: .Sx PROMPTS
805: for more details.
1.12 jmc 806: .It Xo
807: .Fl p Ns Ar pattern |
808: .Fl -pattern Ns = Ns Ar pattern
809: .Xc
810: The -p option on the command line is equivalent to specifying +/pattern;
811: that is, it tells
812: .Nm
813: to start at the first occurrence of pattern in the file.
814: .It Fl Q | -QUIET | -SILENT
815: Causes totally "quiet" operation: the terminal bell is never rung.
1.1 millert 816: .It Fl q | -quiet | -silent
817: Causes moderately "quiet" operation:
818: the terminal bell is not rung if an attempt is made to scroll past the end
819: of the file or before the beginning of the file.
820: If the terminal has a "visual bell", it is used instead.
821: The bell will be rung on certain other errors,
822: such as typing an invalid character.
823: The default is to ring the terminal bell in all such cases.
824: .It Fl R | -RAW-CONTROL-CHARS
1.23 shadchin 825: Like -r, but only ANSI "color" escape sequences are output in "raw" form.
826: Unlike -r, the screen appearance is maintained correctly in most cases.
827: ANSI "color" escape sequences are sequences of the form:
1.1 millert 828: .Pp
1.18 jmc 829: .Dl ESC \&[ ... m
1.1 millert 830: .Pp
1.23 shadchin 831: where the "..." is zero or more color specification characters.
1.1 millert 832: For the purpose of keeping track of screen appearance,
1.23 shadchin 833: ANSI color escape sequences are assumed to not move the cursor.
1.1 millert 834: You can make
835: .Nm
836: think that characters other than "m" can end ANSI color escape sequences
837: by setting the environment variable
838: .Ev LESSANSIENDCHARS
839: to the list of characters which can end a color escape sequence.
1.23 shadchin 840: And you can make
841: .Nm
842: think that characters other than the standard ones may appear between
843: the ESC and the m by setting the environment variable
844: .Ev LESSANSIMIDCHARS
845: to the list of characters which can appear.
1.12 jmc 846: .It Fl r | -raw-control-chars
847: Causes "raw" control characters to be displayed.
848: The default is to display control characters using the caret notation;
849: for example, a control-A (octal 001) is displayed as "^A".
850: Warning: when the -r option is used,
851: .Nm
852: cannot keep track of the actual appearance of the screen
853: (since this depends on how the screen responds to
854: each type of control character).
855: Thus, various display problems may result,
856: such as long lines being split in the wrong place.
1.1 millert 857: .It Fl S | -chop-long-lines
858: Causes lines longer than the screen width to be chopped rather than folded.
859: That is, the portion of a long line that does not fit in
860: the screen width is not shown.
861: The default is to fold long lines; that is, display the remainder
862: on the next line.
1.12 jmc 863: .It Fl s | -squeeze-blank-lines
864: Causes consecutive blank lines to be squeezed into a single blank line.
865: .It Xo
866: .Fl T Ns Ar tagsfile |
867: .Fl -tag-file Ns = Ns Ar tagsfile
868: .Xc
869: Specifies a tags file to be used instead of "tags".
1.1 millert 870: .It Xo
871: .Fl t Ns Ar tag |
1.8 jmc 872: .Fl -tag Ns = Ns Ar tag
1.1 millert 873: .Xc
874: The -t option, followed immediately by a TAG,
875: will edit the file containing that tag.
876: For this to work, tag information must be available;
877: for example, there may be a file in the current directory called "tags",
878: which was previously built by
879: .Xr ctags 1
880: or an equivalent command.
881: If the environment variable
882: .Ev LESSGLOBALTAGS
883: is set, it is taken to be the name of a command compatible with
884: .Xr global ,
885: and that command is executed to find the tag.
886: (See http://www.gnu.org/software/global/global.html).
887: The -t option may also be specified from within
888: .Nm
889: (using the \- command) as a way of examining a new file.
890: The command ":t" is equivalent to specifying -t from within
891: .Nm less .
892: .It Fl U | -UNDERLINE-SPECIAL
893: Causes backspaces, tabs and carriage returns to be
894: treated as control characters;
895: that is, they are handled as specified by the -r option.
896: .Pp
897: By default, if neither -u nor -U is given, backspaces which appear adjacent
898: to an underscore character are treated specially:
899: the underlined text is displayed
900: using the terminal's hardware underlining capability.
901: Also, backspaces which appear between two identical characters
902: are treated specially:
903: the overstruck text is printed
904: using the terminal's hardware boldface capability.
905: Other backspaces are deleted, along with the preceding character.
906: Carriage returns immediately followed by a newline are deleted.
907: Other carriage returns are handled as specified by the -r option.
908: Text which is overstruck or underlined can be searched for
909: if neither -u nor -U is in effect.
1.12 jmc 910: .It Fl u | -underline-special
911: Causes backspaces and carriage returns to be treated as printable characters;
912: that is, they are sent to the terminal when they appear in the input.
1.1 millert 913: .It Fl V | -version
914: Displays the version number of
915: .Nm less .
1.12 jmc 916: .It Fl W | -HILITE-UNREAD
917: Like -w, but temporarily highlights the first new line after any
918: forward movement command larger than one line.
1.1 millert 919: .It Fl w | -hilite-unread
920: Temporarily highlights the first "new" line after a forward movement
921: of a full page.
922: The first "new" line is the line immediately following the line previously
923: at the bottom of the screen.
924: Also highlights the target line after a g or p command.
925: The highlight is removed at the next command which causes movement.
926: The entire line is highlighted, unless the -J option is in effect,
927: in which case only the status column is highlighted.
1.12 jmc 928: .It Fl X | -no-init
929: Disables sending the termcap initialization and deinitialization strings
930: to the terminal.
931: This is sometimes desirable if the deinitialization string does
932: something unnecessary, like clearing the screen.
1.1 millert 933: .It Xo
934: .Fl x Ns Ar n,... |
1.8 jmc 935: .Fl -tabs Ns = Ns Ar n,...
1.1 millert 936: .Xc
937: Sets tab stops.
938: If only one n is specified, tab stops are set at multiples of n.
939: If multiple values separated by commas are specified, tab stops are set at
940: those positions, and then continue with the same spacing as the last two.
941: For example, -x9,17 will set tabs at positions 9, 17, 25, 33, etc.
942: The default for n is 8.
943: .It Xo
944: .Fl y Ns Ar n |
1.8 jmc 945: .Fl -max-forw-scroll Ns = Ns Ar n
1.1 millert 946: .Xc
947: Specifies a maximum number of lines to scroll forward.
948: If it is necessary to scroll forward more than n lines,
949: the screen is repainted instead.
950: The -c or -C option may be used to repaint from the top of
951: the screen if desired.
952: By default, any forward movement causes scrolling.
953: .It Xo
954: .Fl Oo Cm z Oc Ns Ar n |
1.8 jmc 955: .Fl -window Ns = Ns Ar n
1.1 millert 956: .Xc
957: Changes the default scrolling window size to n lines.
958: The default is one screenful.
959: The z and w commands can also be used to change the window size.
1.23 shadchin 960: The "z" may be omitted for compatibility with some versions of
1.1 millert 961: .Nm more .
962: If the number
963: .Ar n
964: is negative, it indicates
965: .Ar n
966: lines less than the current screen size.
967: For example, if the screen is 24 lines, -z-4 sets the
968: scrolling window to 20 lines.
969: If the screen is resized to 40 lines,
970: the scrolling window automatically changes to 36 lines.
1.23 shadchin 971: .It Fl -follow-name
972: Normally, if the input file is renamed while an F command is executing,
973: .Nm
974: will continue to display the contents of the original file despite
975: its name change.
976: If --follow-name is specified, during an F command
977: .Nm
978: will periodically attempt to reopen the file by name.
979: If the reopen succeeds and the file is a different file from the original
980: (which means that a new file has been created
981: with the same name as the original (now renamed) file),
982: .Nm
983: will display the contents of that new file.
1.12 jmc 984: .It Fl -no-keypad
985: Disables sending the keypad initialization and deinitialization strings
986: to the terminal.
987: This is sometimes useful if the keypad strings make the numeric
988: keypad behave in an undesirable manner.
1.1 millert 989: .It Xo
990: .Ar -cc |
1.8 jmc 991: .Fl -quotes Ns = Ns Ar cc
1.1 millert 992: .Xc
993: Changes the filename quoting character.
994: This may be necessary if you are trying to name a file
995: which contains both spaces and quote characters.
996: Followed by a single character, this changes the quote character to that
997: character.
998: Filenames containing a space should then be surrounded by that character
999: rather than by double quotes.
1000: Followed by two characters, changes the open quote to the first character,
1001: and the close quote to the second character.
1002: Filenames containing a space should then be preceded by the open quote
1003: character and followed by the close quote character.
1004: Note that even after the quote characters are changed, this option
1005: remains -" (a dash followed by a double quote).
1006: .It Fl ~ | -tilde
1007: Normally lines after end of file are displayed as a single tilde (~).
1008: This option causes lines after end of file to be displayed as blank lines.
1009: .It Fl # | -shift
1010: Specifies the default number of positions to scroll horizontally
1011: in the RIGHTARROW and LEFTARROW commands.
1012: If the number specified is zero, it sets the default number of
1013: positions to one half of the screen width.
1.23 shadchin 1014: Alternately, the number may be specified as a fraction of the width
1015: of the screen, starting with a decimal point: .5 is half of the
1016: screen width, .3 is three tenths of the screen width, and so on.
1017: If the number is specified as a fraction, the actual number of
1018: scroll positions is recalculated if the terminal window is resized,
1019: so that the actual scroll remains at the specified fraction
1020: of the screen width.
1.1 millert 1021: .It Fl -
1022: A command line argument of "--" marks the end of option arguments.
1023: Any arguments following this are interpreted as filenames.
1024: This can be useful when viewing a file whose name begins with a "-" or "+".
1025: .It Cm +
1026: If a command line option begins with +,
1027: the remainder of that option is taken to be an initial command to
1028: .Nm less .
1029: For example, +G tells
1030: .Nm
1031: to start at the end of the file rather than the beginning,
1032: and +/xyz tells it to start at the first occurrence of "xyz" in the file.
1033: As a special case, +<number> acts like +<number>g;
1034: that is, it starts the display at the specified line number
1035: (however, see the caveat under the "g" command above).
1036: If the option starts with ++, the initial command applies to
1037: every file being viewed, not just the first one.
1038: The + command described previously
1039: may also be used to set (or change) an initial command for every file.
1040: .El
1041: .Sh LINE EDITING
1042: When entering command line at the bottom of the screen
1043: (for example, a filename for the :e command,
1044: or the pattern for a search command),
1045: certain keys can be used to manipulate the command line.
1046: Most commands have an alternate form in [ brackets ] which can be used if
1047: a key does not exist on a particular keyboard.
1.23 shadchin 1048: .\" (Note that the forms beginning with ESC do not work
1049: .\" in some MS-DOS and Windows systems because ESC is the line erase character.)
1.1 millert 1050: Any of these special keys may be entered literally by preceding
1051: it with the "literal" character, either ^V or ^A.
1052: A backslash itself may also be entered literally by entering two backslashes.
1053: .Bl -tag -width Ds
1054: .It LEFTARROW [ ESC-h ]
1055: Move the cursor one space to the left.
1056: .It RIGHTARROW [ ESC-l ]
1057: Move the cursor one space to the right.
1058: .It ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
1059: (That is, CONTROL and LEFTARROW simultaneously.)
1060: Move the cursor one word to the left.
1061: .It ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
1062: (That is, CONTROL and RIGHTARROW simultaneously.)
1063: Move the cursor one word to the right.
1064: .It HOME [ ESC-0 ]
1065: Move the cursor to the beginning of the line.
1066: .It END [ ESC-$ ]
1067: Move the cursor to the end of the line.
1068: .It BACKSPACE
1069: Delete the character to the left of the cursor,
1070: or cancel the command if the command line is empty.
1071: .It DELETE or [ ESC-x ]
1072: Delete the character under the cursor.
1073: .It ^BACKSPACE [ ESC-BACKSPACE ]
1074: (That is, CONTROL and BACKSPACE simultaneously.)
1075: Delete the word to the left of the cursor.
1076: .It ^DELETE [ ESC-X or ESC-DELETE ]
1077: (That is, CONTROL and DELETE simultaneously.)
1078: Delete the word under the cursor.
1079: .It UPARROW [ ESC-k ]
1080: Retrieve the previous command line.
1081: .It DOWNARROW [ ESC-j ]
1082: Retrieve the next command line.
1083: .It TAB
1084: Complete the partial filename to the left of the cursor.
1085: If it matches more than one filename, the first match
1086: is entered into the command line.
1087: Repeated TABs will cycle through the other matching filenames.
1088: If the completed filename is a directory, a "/" is appended to the filename.
1089: .\" (On MS-DOS systems, a "\e" is appended.)
1090: The environment variable
1091: .Ev LESSSEPARATOR
1092: can be used to specify a different character to append to a directory name.
1093: .It BACKTAB [ ESC-TAB ]
1094: Like TAB, but cycles in the reverse direction through the matching filenames.
1095: .It ^L
1096: Complete the partial filename to the left of the cursor.
1097: If it matches more than one filename, all matches are entered into
1098: the command line (if they fit).
1099: .\" .It ^U (Unix and OS/2) or ESC (MS-DOS)
1100: .It ^U
1101: Delete the entire command line,
1102: or cancel the command if the command line is empty.
1103: If you have changed your line-kill character to something
1104: other than ^U, that character is used instead of ^U.
1.23 shadchin 1105: .It "^G"
1106: Delete the entire command line and return to the main prompt.
1.1 millert 1107: .El
1108: .Sh KEY BINDINGS
1109: You may define your own
1110: .Nm
1111: commands by using the program
1112: .Xr lesskey 1
1113: to create a lesskey file.
1114: This file specifies a set of command keys and an action
1115: associated with each key.
1116: You may also use lesskey
1117: to change the line-editing keys (see
1118: .Sx LINE EDITING ) ,
1119: and to set environment variables.
1120: If the environment variable
1121: .Ev LESSKEY
1122: is set,
1123: .Nm
1124: uses that as the name of the lesskey file.
1125: Otherwise,
1126: .Nm
1127: looks for a lesskey file called "$HOME/.less".
1128: .\" On MS-DOS and Windows systems,
1129: .\" .I less
1130: .\" looks for a lesskey file called "$HOME/_less", and if it is not found there,
1131: .\" then looks for a lesskey file called "_less" in any directory specified
1132: .\" in the PATH environment variable.
1133: .\" On OS/2 systems,
1134: .\" .I less
1135: .\" looks for a lesskey file called "$HOME/less.ini", and if it is not found,
1136: .\" then looks for a lesskey file called "less.ini" in any directory specified
1137: .\" in the INIT environment variable, and if it not found there,
1138: .\" then looks for a lesskey file called "less.ini" in any directory specified
1139: .\" in the PATH environment variable.
1140: See the
1141: .Xr lesskey 1
1142: manual page for more details.
1143: .Pp
1144: A system-wide lesskey file may also be set up to provide key bindings.
1145: If a key is defined in both a local lesskey file and in the
1146: system-wide file, key bindings in the local file take precedence over
1147: those in the system-wide file.
1148: If the environment variable
1149: .Ev LESSKEY_SYSTEM
1150: is set,
1151: .Nm
1152: uses that as the name of the system-wide lesskey file.
1153: Otherwise,
1154: .Nm
1155: looks in a standard place for the system-wide lesskey file:
1156: On
1157: .Ox ,
1158: the system-wide lesskey file is
1159: .Pa /etc/sysless .
1160: .\" On Unix systems, the system-wide lesskey file is /usr/local/etc/sysless.
1161: .\" (However, if
1162: .\" .Nm less
1163: .\" was built with a different sysconf directory than /usr/local/etc,
1164: .\" that directory is where the sysless file is found.)
1165: .\" On MS-DOS and Windows systems, the system-wide lesskey file is c:\e_sysless.
1166: .\" On OS/2 systems, the system-wide lesskey file is c:\esysless.ini.
1167: .Sh INPUT PREPROCESSOR
1168: You may define an "input preprocessor" for
1169: .Nm less .
1170: Before
1171: .Nm less
1172: opens a file, it first gives your input preprocessor a chance to modify the
1173: way the contents of the file are displayed.
1174: An input preprocessor is simply an executable program (or shell script),
1175: which writes the contents of the file to a different file,
1176: called the replacement file.
1177: The contents of the replacement file are then displayed
1178: in place of the contents of the original file.
1179: However, it will appear to the user as if the original file is opened;
1180: that is,
1181: .Nm less
1182: will display the original filename as the name of the current file.
1183: .Pp
1184: An input preprocessor receives one command line argument, the original filename,
1185: as entered by the user.
1186: It should create the replacement file, and when finished
1187: print the name of the replacement file to its standard output.
1188: If the input preprocessor does not output a replacement filename,
1189: .Nm
1190: uses the original file, as normal.
1191: The input preprocessor is not called when viewing standard input.
1192: To set up an input preprocessor, set the
1193: .Ev LESSOPEN
1194: environment variable to a command line which will invoke your
1195: input preprocessor.
1196: This command line should include one occurrence of the string "%s",
1197: which will be replaced by the filename
1198: when the input preprocessor command is invoked.
1199: .Pp
1200: When
1201: .Nm
1202: closes a file opened in such a way, it will call another program,
1203: called the input postprocessor,
1204: which may perform any desired clean-up action (such as deleting the
1205: replacement file created by
1206: .Ev LESSOPEN ) .
1207: This program receives two command line arguments, the original filename
1208: as entered by the user, and the name of the replacement file.
1209: To set up an input postprocessor, set the
1210: .Ev LESSCLOSE
1211: environment variable to a command line which will invoke your
1212: input postprocessor.
1213: It may include two occurrences of the string "%s";
1214: the first is replaced with the original name of the file and the second
1215: with the name of the replacement file, which was output by
1216: .Ev LESSOPEN .
1217: .Pp
1218: For example, these two scripts will allow you
1219: to keep files in compressed format, but still let
1220: .Nm
1221: view them directly:
1222: .Pp
1223: lessopen.sh:
1224: .Bd -literal -offset indent
1225: #! /bin/sh
1226: case "$1" in
1227: *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1228: if [ -s /tmp/less.$$ ]; then
1229: echo /tmp/less.$$
1230: else
1231: rm -f /tmp/less.$$
1232: fi
1233: ;;
1234: esac
1235: .Ed
1236: .Pp
1237: lessclose.sh:
1238: .Bd -literal -offset indent
1239: #! /bin/sh
1240: rm $2
1241: .Ed
1242: .Pp
1243: To use these scripts, put them both where they can be executed and
1244: set LESSOPEN="lessopen.sh\ %s", and LESSCLOSE="lessclose.sh\ %s\ %s".
1245: More complex LESSOPEN and LESSCLOSE scripts may be written
1246: to accept other types of compressed files, and so on.
1247: .Pp
1248: It is also possible to set up an input preprocessor to
1249: pipe the file data directly to
1250: .Nm less ,
1251: rather than putting the data into a replacement file.
1252: This avoids the need to decompress the entire file before starting to view it.
1253: An input preprocessor that works this way is called an input pipe.
1254: An input pipe, instead of writing the name of a replacement file on
1255: its standard output,
1256: writes the entire contents of the replacement file on its standard output.
1257: If the input pipe does not write any characters on its standard output,
1258: then there is no replacement file and
1259: .Nm
1260: uses the original file, as normal.
1261: To use an input pipe, make the first character in the
1262: .Ev LESSOPEN
1263: environment variable a vertical bar (|) to signify that the
1264: input preprocessor is an input pipe.
1265: .Pp
1266: For example, this script will work like the previous example scripts:
1267: .Pp
1268: lesspipe.sh:
1269: .Bd -literal -offset indent
1270: #! /bin/sh
1271: case "$1" in
1272: *.Z) uncompress -c $1 2>/dev/null
1273: ;;
1274: esac
1275: .Ed
1276: .Pp
1277: To use this script, put it where it can be executed and set
1278: LESSOPEN="|lesspipe.sh %s".
1279: When an input pipe is used, a LESSCLOSE postprocessor can be used,
1280: but it is usually not necessary since there is no replacement file to clean up.
1281: In this case, the replacement file name passed to the LESSCLOSE
1282: postprocessor is "-".
1.23 shadchin 1283: .Pp
1284: For compatibility with previous versions of
1285: .Nm less ,
1286: the input preprocessor or pipe is not used if
1287: .Nm
1288: is viewing standard input.
1289: However, if the first character of LESSOPEN is a dash (-),
1290: the input preprocessor is used on standard input as well as other files.
1291: In this case, the dash is not considered to be part of
1292: the preprocessor command.
1293: If standard input is being viewed, the input preprocessor is passed
1294: a file name consisting of a single dash.
1295: Similarly, if the first two characters of LESSOPEN are vertical bar and dash
1296: (|-), the input pipe is used on standard input as well as other files.
1297: Again, in this case the dash is not considered to be part of
1298: the input pipe command.
1.1 millert 1299: .Sh NATIONAL CHARACTER SETS
1300: There are three types of characters in the input file:
1301: .Bl -tag -width "control characters"
1302: .It normal characters
1303: Can be displayed directly to the screen.
1304: .It control characters
1305: Should not be displayed directly, but are expected to be found
1306: in ordinary text files (such as backspace and tab).
1307: .It binary characters
1308: Should not be displayed directly and are not expected to be found
1309: in text files.
1310: .El
1311: .Pp
1312: A "character set" is simply a description of which characters are to
1313: be considered normal, control, and binary.
1314: The
1315: .Ev LESSCHARSET
1316: environment variable may be used to select a character set.
1317: Possible values for
1318: .Ev LESSCHARSET
1319: are:
1320: .Bl -tag -width "IBM-1047"
1321: .It ascii
1322: BS, TAB, NL, CR, and formfeed are control characters,
1323: all chars with values between 32 and 126 are normal,
1324: and all others are binary.
1325: .It iso8859
1326: Selects an ISO 8859 character set.
1327: This is the same as ASCII, except characters between 160 and 255 are
1328: treated as normal characters.
1329: .It latin1
1330: Same as iso8859.
1331: .It latin9
1332: Same as iso8859.
1333: .It dos
1334: Selects a character set appropriate for MS-DOS.
1335: .It ebcdic
1336: Selects an EBCDIC character set.
1337: .It IBM-1047
1.17 sobrado 1338: Selects an EBCDIC character set used by OS/390
1339: .Ux
1340: Services.
1.1 millert 1341: This is the EBCDIC analogue of latin1.
1342: You get similar results by setting either LESSCHARSET=IBM-1047 or
1343: LC_CTYPE=en_US in your environment.
1344: .It koi8-r
1345: Selects a Russian character set.
1346: .It next
1347: Selects a character set appropriate for NeXT computers.
1348: .It utf-8
1349: Selects the UTF-8 encoding of the ISO 10646 character set.
1.23 shadchin 1350: UTF-8 is special in that it supports multi-byte characters in the input file.
1351: It is the only character set that supports multi-byte characters.
1352: .It windows
1353: Selects a character set appropriate for Microsoft Windows (cp 1251).
1.1 millert 1354: .El
1355: .Pp
1.23 shadchin 1356: In rare cases, it may be desired to tailor
1.1 millert 1357: .Nm
1358: to use a character set other than the ones definable by LESSCHARSET.
1359: In this case, the environment variable
1360: .Ev LESSCHARDEF
1361: can be used to define a character set.
1362: It should be set to a string where each character in the string represents
1363: one character in the character set.
1364: The character "." is used for a normal character, "c" for control,
1365: and "b" for binary.
1366: A decimal number may be used for repetition.
1367: For example, "bccc4b." would mean character 0 is binary,
1368: 1, 2 and 3 are control, 4, 5, 6 and 7 are binary, and 8 is normal.
1369: All characters after the last are taken to be the same as the last,
1370: so characters 9 through 255 would be normal.
1371: (This is an example, and does not necessarily
1372: represent any real character set.)
1373: .Pp
1374: This table shows the value of LESSCHARDEF which is equivalent
1375: to each of the possible values for LESSCHARSET:
1376: .Bd -literal -offset indent
1377: ascii 8bcccbcc18b95.b
1378: dos 8bcccbcc12bc5b95.b.
1379: ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b
1380: 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.
1381: IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc
1382: 191.b
1383: iso8859 8bcccbcc18b95.33b.
1384: koi8-r 8bcccbcc18b95.b128.
1385: latin1 8bcccbcc18b95.33b.
1386: next 8bcccbcc18b95.bb125.bb
1387: .Ed
1388: .Pp
1389: If neither LESSCHARSET nor LESSCHARDEF is set,
1.23 shadchin 1390: but any of the strings "UTF-8", "UTF8", "utf-8" or "utf8" is found in the
1.21 jmc 1391: .Ev LC_ALL , LC_CTYPE
1.1 millert 1392: or
1393: .Ev LANG
1394: environment variables, then the default character set is utf-8.
1395: .Pp
1396: If that string is not found, but your system supports the
1397: setlocale interface,
1398: .Nm
1399: will use setlocale to determine the character set.
1400: setlocale is controlled by setting the
1401: .Ev LANG
1402: or
1403: .Ev LC_CTYPE
1404: environment variables.
1405: .Pp
1406: Finally, if the
1407: setlocale interface is also not available, the default character set is latin1.
1408: .Pp
1409: Control and binary characters are displayed in standout (reverse video).
1410: Each such character is displayed in caret notation if possible
1411: (e.g. ^A for control-A).
1412: Caret notation is used only if inverting the 0100 bit results in a
1413: normal printable character.
1414: Otherwise, the character is displayed as a hex number in angle brackets.
1415: This format can be changed by setting the
1416: .Ev LESSBINFMT
1417: environment variable.
1418: LESSBINFMT may begin with a "*" and one character to select
1419: the display attribute:
1420: "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1421: and "*n" is normal.
1422: If LESSBINFMT does not begin with a "*", normal attribute is assumed.
1423: The remainder of LESSBINFMT is a string which may include one
1424: printf-style escape sequence (a % followed by x, X, o, d, etc.).
1425: For example, if LESSBINFMT is "*u[%x]", binary characters
1426: are displayed in underlined hexadecimal surrounded by brackets.
1.23 shadchin 1427: The default if no LESSBINFMT is specified is "*s<%02X>".
1428: Warning: the result of expanding the character via LESSBINFMT must
1429: be less than 31 characters.
1430: .Pp
1431: When the character set is utf-8, the
1432: .Ev LESSUTFBINFMT
1433: environment variable
1434: acts similarly to LESSBINFMT but it applies to Unicode code points
1435: that were successfully decoded but are unsuitable for display (e.g.,
1436: unassigned code points).
1437: Its default value is "<U+%04lX>".
1438: Note that LESSUTFBINFMT and LESSBINFMT share their display attribute
1439: setting ("*x") so specifying one will affect both;
1440: LESSUTFBINFMT is read after LESSBINFMT so its setting, if any,
1441: will have priority.
1442: Problematic octets in a UTF-8 file (octets of a truncated sequence,
1443: octets of a complete but non-shortest form sequence, illegal octets,
1444: and stray trailing octets)
1445: are displayed individually using LESSBINFMT so as to facilitate diagnostic
1446: of how the UTF-8 file is ill-formed.
1.1 millert 1447: .Sh PROMPTS
1448: The -P option allows you to tailor the prompt to your preference.
1449: The string given to the -P option replaces the specified prompt string.
1450: Certain characters in the string are interpreted specially.
1451: The prompt mechanism is rather complicated to provide flexibility,
1452: but the ordinary user need not understand the details of constructing
1453: personalized prompt strings.
1454: .Pp
1455: A percent sign followed by a single character is expanded
1456: according to what the following character is:
1457: .Bl -tag -width Ds
1458: .It %b Ns Ar X
1459: Replaced by the byte offset into the current input file.
1460: The b is followed by a single character (shown as
1461: .Ar X
1462: above) which specifies the line whose byte offset is to be used.
1463: If the character is a "t", the byte offset of the top line in the
1464: display is used,
1465: an "m" means use the middle line,
1466: a "b" means use the bottom line,
1467: a "B" means use the line just after the bottom line,
1468: and a "j" means use the "target" line, as specified by the -j option.
1.4 jmc 1469: .It \&%B
1.1 millert 1470: Replaced by the size of the current input file.
1471: .It %c
1472: Replaced by the column number of the text appearing in the first
1473: column of the screen.
1474: .It %d Ns Ar X
1475: Replaced by the page number of a line in the input file.
1476: The line to be used is determined by the
1477: .Ar X ,
1478: as with the %b option.
1.4 jmc 1479: .It \&%D
1.1 millert 1480: Replaced by the number of pages in the input file,
1481: or equivalently, the page number of the last line in the input file.
1482: .It %E
1483: Replaced by the name of the editor (from the
1484: .Ev VISUAL
1485: environment variable, or the
1486: .Ev EDITOR
1487: environment variable if
1488: .Ev VISUAL
1489: is not defined).
1490: See the discussion of the LESSEDIT feature below.
1491: .It %f
1492: Replaced by the name of the current input file.
1.23 shadchin 1493: .It %F
1494: Replaced by the last component of the name of the current input file.
1.1 millert 1495: .It %i
1496: Replaced by the index of the current file in the list of
1497: input files.
1498: .It %l Ns Ar X
1499: Replaced by the line number of a line in the input file.
1500: The line to be used is determined by the
1501: .Ar X ,
1502: as with the %b option.
1503: .It %L
1504: Replaced by the line number of the last line in the input file.
1505: .It %m
1506: Replaced by the total number of input files.
1507: .It %p Ns Ar X
1508: Replaced by the percent into the current input file, based on byte offsets.
1509: The line used is determined by the
1510: .Ar X ,
1511: as with the %b option.
1.4 jmc 1512: .It \&%P Ns Ar X
1.1 millert 1513: Replaced by the percent into the current input file, based on line numbers.
1514: The line used is determined by the
1515: .Ar X ,
1516: as with the %b option.
1517: .It %s
1518: Same as %B.
1519: .It %t
1520: Causes any trailing spaces to be removed.
1521: Usually used at the end of the string, but may appear anywhere.
1522: .It %x
1523: Replaced by the name of the next input file in the list.
1524: .El
1525: .Pp
1526: If any item is unknown (for example, the file size if input is a pipe),
1527: a question mark is printed instead.
1528: .Pp
1529: The format of the prompt string can be changed depending on certain conditions.
1530: A question mark followed by a single character acts like an "IF":
1531: depending on the following character, a condition is evaluated.
1532: If the condition is true, any characters following the question mark
1533: and condition character, up to a period, are included in the prompt.
1534: If the condition is false, such characters are not included.
1535: A colon appearing between the question mark and the
1536: period can be used to establish an "ELSE": any characters between
1537: the colon and the period are included in the string, if and only if
1538: the IF condition is false.
1539: Condition characters (which follow a question mark) may be:
1540: .Bl -tag -width Ds
1541: .It ?a
1542: True if any characters have been included in the prompt so far.
1543: .It ?b Ns Ar X
1544: True if the byte offset of the specified line is known.
1545: .It ?B
1546: True if the size of the current input file is known.
1547: .It ?c
1548: True if the text is horizontally shifted (%c is not zero).
1549: .It ?d Ns Ar X
1550: True if the page number of the specified line is known.
1551: .It ?e
1552: True if at end-of-file.
1553: .It ?f
1554: True if there is an input filename
1555: (that is, if input is not a pipe).
1556: .It ?l Ns Ar X
1557: True if the line number of the specified line is known.
1558: .It ?L
1559: True if the line number of the last line in the file is known.
1560: .It ?m
1561: True if there is more than one input file.
1562: .It ?n
1563: True if this is the first prompt in a new input file.
1564: .It ?p Ns Ar X
1565: True if the percent into the current input file, based on byte offsets,
1566: of the specified line is known.
1567: .It ?P Ns Ar X
1568: True if the percent into the current input file, based on line numbers,
1569: of the specified line is known.
1570: .It ?s
1571: Same as "?B".
1572: .It ?x
1573: True if there is a next input file
1574: (that is, if the current input file is not the last one).
1575: .El
1576: .Pp
1577: Any characters other than the special ones
1578: (question mark, colon, period, percent, and backslash)
1579: become literally part of the prompt.
1580: Any of the special characters may be included in the prompt literally
1581: by preceding it with a backslash.
1582: .Pp
1583: Some examples:
1584: .Pp
1585: .Dl ?f%f:Standard input.
1586: .Pp
1587: This prompt prints the filename, if known;
1588: otherwise the string "Standard input".
1589: .Pp
1590: .Dl ?f%f .?ltLine %lt:?pt%pt\e%:?btByte %bt:-...
1591: .Pp
1592: This prompt would print the filename, if known.
1593: The filename is followed by the line number, if known,
1594: otherwise the percent if known, otherwise the byte offset if known.
1595: Otherwise, a dash is printed.
1596: Notice how each question mark has a matching period,
1597: and how the % after the %pt
1598: is included literally by escaping it with a backslash.
1599: .Pp
1600: .Dl ?n?f%f\ .?m(file\ %i\ of\ %m)\ ..?e(END)\ ?x-\ Next\e:\ %x..%t
1601: .Pp
1602: This prints the filename if this is the first prompt in a file,
1603: followed by the "file N of N" message if there is more
1604: than one input file.
1605: Then, if we are at end-of-file, the string "(END)" is printed
1606: followed by the name of the next file, if there is one.
1607: Finally, any trailing spaces are truncated.
1608: This is the default prompt.
1609: For reference, here are the defaults for
1610: the other two prompts (-m and -M respectively).
1611: Each is broken into two lines here for readability only.
1612: .Bd -literal -offset indent
1.19 ray 1613: ?f%f\ .?m(file\ %i\ of\ %m)\ .?e(END)\ ?x-\ Next\e:\ %x.:
1.1 millert 1614: ?pB%pB\e%:byte\ %bB?s/%s...%t
1615:
1616: ?f%f\ .?n?m(file\ %i\ of\ %m)\ ..?ltlines\ %lt-%lb?L/%L.\ :
1617: byte\ %bB?s/%s.\ .?e(END)\ ?x-\ Next\e:\ %x.:?pB%pB\e%..%t
1618: .Ed
1619: .Pp
1620: And here is the default message produced by the = command:
1621: .Bd -literal -offset indent
1622: ?f%f\ .?m(file\ %i\ of\ %m)\ .?ltlines\ %lt-%lb?L/%L.\ .
1623: byte\ %bB?s/%s.\ ?e(END)\ :?pB%pB\e%..%t
1624: .Ed
1625: .Pp
1626: The prompt expansion features are also used for another purpose:
1627: if an environment variable
1628: .Ev LESSEDIT
1629: is defined, it is used as the command to be executed when the v command
1630: is invoked.
1631: The LESSEDIT string is expanded in the same way as the prompt strings.
1632: The default value for LESSEDIT is:
1633: .Pp
1634: .Dl %E\ ?lm+%lm.\ %f
1635: .Pp
1636: Note that this expands to the editor name, followed by a + and the
1637: line number, followed by the file name.
1638: If your editor does not accept the "+linenumber" syntax, or has other
1639: differences in invocation syntax, the
1640: .Ev LESSEDIT
1641: variable can be changed to modify this default.
1642: .Sh SECURITY
1643: When the environment variable
1644: .Ev LESSSECURE
1645: is set to 1,
1646: .Nm
1647: runs in a "secure" mode.
1648: This means these features are disabled:
1649: .Bl -tag -width Ds
1.6 jmc 1650: .It \&!
1.1 millert 1651: The shell command.
1652: .It |
1653: The pipe command.
1654: .It :e
1655: The examine command.
1656: .It v
1657: The editing command.
1658: .It s -o
1659: Log files.
1660: .It -k
1661: Use of lesskey files.
1662: .It -t
1663: Use of tags files.
1664: .It " "
1665: Metacharacters in filenames, such as "*".
1666: .It " "
1667: Filename completion (TAB, ^L).
1668: .El
1669: .Pp
1670: Less can also be compiled to be permanently in "secure" mode.
1.23 shadchin 1671: .Sh COMPATIBILITY WITH MORE
1672: If the environment variable
1673: .Ev LESS_IS_MORE
1674: is set to 1,
1675: or if the program is invoked via a file link named "more",
1676: .Nm
1677: behaves (mostly) in conformance with the POSIX "more" command specification.
1678: In this mode, less behaves differently in these ways:
1679: .Pp
1680: The -e option works differently.
1681: If the -e option is not set,
1682: .Nm
1683: behaves as if the -E option were set.
1684: If the -e option is set,
1685: .Nm
1686: behaves as if the -e and -F options were set.
1687: .Pp
1688: The -m option works differently.
1689: If the -m option is not set, the medium prompt is used.
1690: If the -m option is set, the short prompt is used.
1691: .Pp
1692: The -n option acts like the -z option.
1693: The normal behavior of the -n option is unavailable in this mode.
1694: .Pp
1695: The parameter to the -p option is taken to be a
1696: .Nm
1697: command rather than a search pattern.
1698: .Pp
1699: The
1700: .Ev LESS
1701: environment variable is ignored, and the
1702: .Ev MORE
1703: environment variable is used in its place.
1.3 jmc 1704: .Sh ENVIRONMENT
1.1 millert 1705: Environment variables may be specified either in the system environment
1706: as usual, or in a
1707: .Xr lesskey 1
1708: file.
1709: If environment variables are defined in more than one place,
1710: variables defined in a local lesskey file take precedence over
1711: variables defined in the system environment, which take precedence
1712: over variables defined in the system-wide lesskey file.
1713: .Bl -tag -width Ds
1714: .It Ev COLUMNS
1715: Sets the number of columns on the screen.
1716: Takes precedence over the number of columns specified by the TERM variable.
1717: (But if you have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1718: the window system's idea of the screen size takes precedence over the
1719: LINES and COLUMNS environment variables.)
1720: .It Ev EDITOR
1721: The name of the editor (used for the v command).
1722: .It Ev HOME
1723: Name of the user's home directory
1724: (used to find a lesskey file).
1725: .\" .It Ev "HOMEDRIVE, HOMEPATH"
1726: .\" Concatenation of the HOMEDRIVE and HOMEPATH environment variables is
1727: .\" the name of the user's home directory if the HOME variable is not set
1728: .\" (only in the Windows version).
1729: .\" .It Ev INIT
1730: .\" Name of the user's init directory
1731: .\" (used to find a lesskey file on OS/2 systems).
1732: .It Ev LANG
1733: Language for determining the character set.
1734: .It Ev LC_CTYPE
1735: Language for determining the character set.
1736: .It Ev LESS
1737: Options which are passed to
1738: .Nm
1739: automatically.
1740: .It Ev LESSANSIENDCHARS
1.23 shadchin 1741: Characters which may end an ANSI color escape sequence
1.1 millert 1742: (default "m").
1.23 shadchin 1743: .It Ev LESSANSIMIDCHARS
1744: Characters which may appear between the ESC character and the
1745: end character in an ANSI color escape sequence
1746: (default "0123456789;[?!"'#%()*+\ ").
1.1 millert 1747: .It Ev LESSBINFMT
1748: Format for displaying non-printable, non-control characters.
1749: .It Ev LESSCHARDEF
1750: Defines a character set.
1751: .It Ev LESSCHARSET
1752: Selects a predefined character set.
1753: .It Ev LESSCLOSE
1754: Command line to invoke the (optional) input-postprocessor.
1755: .\" .It Ev LESSECHO
1756: .\" Name of the lessecho program (default "lessecho").
1757: .\" The lessecho program is needed to expand metacharacters, such as * and ?,
1758: .\" in filenames on Unix systems.
1759: .It Ev LESSEDIT
1760: Editor prototype string (used for the v command).
1761: See discussion under
1762: .Sx PROMPTS .
1763: .It Ev LESSGLOBALTAGS
1764: Name of the command used by the -t option to find global tags.
1765: Normally should be set to "global" if your system has the global command.
1766: If not set, global tags are not used.
1.23 shadchin 1767: .It Ev LESSHISTFILE
1768: Name of the history file used to remember search commands and
1769: shell commands between invocations of
1770: .Nm less .
1771: If set to "-" or "/dev/null", a history file is not used.
1.25 nicm 1772: The default is "-".
1.23 shadchin 1773: .\" The default is "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on
1.24 jmc 1774: .\" DOS and Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini"
1.23 shadchin 1775: .\" on OS/2 systems.
1776: .It Ev LESSHISTSIZE
1777: The maximum number of commands to save in the history file.
1778: The default is 100.
1.1 millert 1779: .It Ev LESSKEY
1780: Name of the default lesskey(1) file.
1781: .It Ev LESSKEY_SYSTEM
1782: Name of the default system-wide lesskey(1) file.
1783: .It Ev LESSMETACHARS
1784: List of characters which are considered "metacharacters" by the shell.
1785: .It Ev LESSMETAESCAPE
1786: Prefix which
1787: .Nm
1788: will add before each metacharacter in a command sent to the shell.
1789: If LESSMETAESCAPE is an empty string, commands containing
1790: metacharacters will not be passed to the shell.
1791: .It Ev LESSOPEN
1792: Command line to invoke the (optional) input-preprocessor.
1793: .It Ev LESSSECURE
1794: Runs less in "secure" mode.
1795: See discussion under
1796: .Sx SECURITY .
1797: .It Ev LESSSEPARATOR
1798: String to be appended to a directory name in filename completion.
1.23 shadchin 1799: .It Ev LESSUTFBINFMT
1800: Format for displaying non-printable Unicode code points.
1801: .It Ev LESS_IS_MORE
1802: Emulate the
1803: .Xr more 1
1804: command.
1.1 millert 1805: .It Ev LINES
1806: Sets the number of lines on the screen.
1807: Takes precedence over the number of lines specified by the TERM variable.
1808: (But if you have a windowing system which supports TIOCGWINSZ or WIOCGETD,
1809: the window system's idea of the screen size takes precedence over the
1810: LINES and COLUMNS environment variables.)
1811: .\" .It Ev PATH
1812: .\" User's search path (used to find a lesskey file
1813: .\" on MS-DOS and OS/2 systems).
1814: .It Ev SHELL
1815: The shell used to execute the ! command, as well as to expand filenames.
1816: .It Ev TERM
1817: The type of terminal on which
1818: .Nm
1819: is being run.
1820: .It Ev VISUAL
1821: The name of the editor (used for the v command).
1822: .El
1823: .Sh SEE ALSO
1824: .Xr lesskey 1
1.13 jmc 1825: .Sh STANDARDS
1826: The
1827: .Nm more
1828: utility is compliant with the
1.15 jmc 1829: .St -p1003.1-2008
1.16 jmc 1830: specification,
1831: though its presence is optional.
1.13 jmc 1832: .Pp
1833: The flags
1834: .Op Fl aBbCdEFfGghIJjkLMmNOoPQqRrSTUVWwXxyz~#
1835: are extensions to that specification.
1.7 jmc 1836: .Sh AUTHORS
1837: .An Mark Nudelman Aq markn@greenwoodsoftware.com
1838: .Pp
1839: Send bug reports or comments to the above address or to
1840: .Aq bug\-less@gnu.org .
1841: .Pp
1842: For more information, see the less homepage at
1843: .Pa http://www.greenwoodsoftware.com/less .
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