Annotation of src/usr.bin/less/less.1, Revision 1.56
1.56 ! jmc 1: .\" $OpenBSD: less.1,v 1.55 2019/07/20 13:21:09 schwarze Exp $
1.1 millert 2: .\"
1.32 shadchin 3: .\" Copyright (C) 1984-2012 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
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1.5 millert 24: .\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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1.56 ! jmc 26: .Dd $Mdocdate: July 20 2019 $
1.1 millert 27: .Dt LESS 1
28: .Os
29: .Sh NAME
1.34 jmc 30: .Nm less
1.11 jmc 31: .Nd view files
1.1 millert 32: .Sh SYNOPSIS
1.34 jmc 33: .Nm less
1.53 schwarze 34: .Op Fl ?~AaBCcdEeFfGgIiJKLMmNnQqRrSsUuVWwX
1.34 jmc 35: .Op Fl b Ar n
36: .Op Fl h Ar n
37: .Op Fl j Ar n
1.1 millert 38: .Op Fl k Ar keyfile
1.12 jmc 39: .Op Fl O | o Ar logfile
40: .Op Fl P Ar prompt
1.1 millert 41: .Op Fl p Ar pattern
1.12 jmc 42: .Op Fl T Ar tagsfile
1.1 millert 43: .Op Fl t Ar tag
1.45 jmc 44: .Op Fl x Ar n , Ns Ar ...
1.34 jmc 45: .Op Fl y Ar n
1.44 bentley 46: .Op Fl z Ar n
1.53 schwarze 47: .Op Fl # Ar n
1.34 jmc 48: .Op Ar
1.1 millert 49: .Sh DESCRIPTION
50: .Nm
1.56 ! jmc 51: displays text one screenful at a time.
! 52: After showing each screenful, it prompts the user for a command,
! 53: as described in
! 54: .Sx COMMANDS .
1.37 jmc 55: When showing the last line of a file,
56: .Nm
57: displays a prompt indicating end of file and the name of the next file
58: to examine, if any.
59: It then waits for input from the user.
1.1 millert 60: .Pp
61: .Nm
1.56 ! jmc 62: is similar to the traditional
! 63: .Xr more 1 ,
! 64: but with many more features.
! 65: .Nm
! 66: will behave like
1.1 millert 67: .Xr more 1
68: if it is called as
1.37 jmc 69: .Nm more ,
70: or if the
71: .Ev LESS_IS_MORE
72: environment variable is set.
73: The main differences between the two are summarized in the
74: .Sx COMPATIBILITY WITH MORE
75: section, below.
76: .Pp
1.1 millert 77: A long option name may be abbreviated as long as the abbreviation is
78: unambiguous.
79: Such option names need only have their first letter capitalized;
80: the remainder of the name may be in either case.
1.44 bentley 81: For example,
82: .Fl -Quit-at-eof
83: is equivalent to
84: .Fl -QUIT-AT-EOF .
1.1 millert 85: .Pp
1.36 jmc 86: The options are as follows:
1.1 millert 87: .Bl -tag -width XXXX
1.6 jmc 88: .It Fl \&? | -help
1.1 millert 89: This option displays a summary of the commands accepted by
90: .Nm
1.44 bentley 91: (the same as the
92: .Ic h
93: command).
1.1 millert 94: (Depending on how your shell interprets the question mark,
1.44 bentley 95: it may be necessary to quote the question mark, thus:
96: .Ql Fl Ns \e? . )
1.23 shadchin 97: .It Fl A | -SEARCH-SKIP-SCREEN
98: Causes all forward searches (not just non-repeated searches)
99: to start just after the target line, and all backward searches
100: to start just before the target line.
101: Thus, forward searches will skip part of the displayed screen
102: (from the first line up to and including the target line).
103: Similarly backwards searches will skip the displayed screen
104: from the last line up to and including the target line.
1.44 bentley 105: This was the default behavior in
106: .Nm
107: versions prior to 441.
1.1 millert 108: .It Fl a | -search-skip-screen
1.23 shadchin 109: By default, forward searches start at the top of the displayed screen
110: and backwards searches start at the bottom of the displayed screen
1.44 bentley 111: (except for repeated searches invoked by the
112: .Ic n
113: or
114: .Ic N
115: commands,
116: which start after or before the
117: .Dq target
118: line respectively; see the
119: .Fl j
120: option for more about the target line).
121: The
122: .Fl a
123: option causes forward searches to instead start at the bottom of the screen
1.23 shadchin 124: and backward searches to start at the top of the screen,
1.1 millert 125: thus skipping all lines displayed on the screen.
1.12 jmc 126: .It Fl B | -auto-buffers
127: By default, when data is read from a pipe,
128: buffers are allocated automatically as needed.
129: If a large amount of data is read from the pipe, this can cause
130: a large amount of memory to be allocated.
1.44 bentley 131: The
132: .Fl B
133: option disables this automatic allocation of buffers for pipes,
134: so that only 64K (or the amount of space specified by the
135: .Fl b
136: option) is used for the pipe.
137: .Sy Warning :
138: use of
139: .Fl B
140: can result in erroneous display, since only the
1.23 shadchin 141: most recently viewed part of the piped data is kept in memory;
1.12 jmc 142: any earlier data is lost.
1.44 bentley 143: .It Fl b Ar n | Fl -buffers Ns = Ns Ar n
1.1 millert 144: Specifies the amount of buffer space
145: .Nm
146: will use for each file, in units of kilobytes (1024 bytes).
147: By default 64K of buffer space is used for each file
1.44 bentley 148: (unless the file is a pipe; see the
149: .Fl B
150: option).
151: The
152: .Fl b
153: option specifies instead that
154: .Ar n
155: kilobytes of buffer space should be used for each file.
156: If
157: .Ar n
158: is -1, buffer space is unlimited; that is,
1.23 shadchin 159: the entire file can be read into memory.
1.12 jmc 160: .It Fl C | -CLEAR-SCREEN
1.44 bentley 161: Same as
162: .Fl c ,
163: for compatibility with older versions of
164: .Nm .
1.1 millert 165: .It Fl c | -clear-screen
1.27 jmc 166: Causes full screen repaints to be painted from the bottom of the screen.
167: By default, full screen repaints are done from the top line down
168: to avoid the position of the display being moved
1.26 nicm 169: when using interactive commands.
1.33 millert 170: .It Fl d | -dumb
1.44 bentley 171: The
172: .Fl d
173: option suppresses the error message normally displayed if the terminal is dumb;
174: that is, if the terminal lacks some important capability,
1.1 millert 175: such as the ability to clear the screen or scroll backward.
1.44 bentley 176: The
177: .Fl d
178: option does not otherwise change the behavior of
1.1 millert 179: .Nm
180: on a dumb terminal.
1.12 jmc 181: .It Fl E | -QUIT-AT-EOF
182: Causes
183: .Nm
184: to automatically exit the first time it reaches end-of-file.
1.1 millert 185: .It Fl e | -quit-at-eof
186: Causes
187: .Nm
188: to automatically exit the second time it reaches end-of-file.
189: By default, the only way to exit
190: .Nm
1.44 bentley 191: is via the
192: .Ic q
193: command.
1.12 jmc 194: .It Fl F | -quit-if-one-screen
1.1 millert 195: Causes
196: .Nm
1.12 jmc 197: to automatically exit if the entire file can be displayed on the first screen.
1.1 millert 198: .It Fl f | -force
199: Forces non-regular files to be opened.
200: (A non-regular file is a directory or a device special file.)
201: Also suppresses the warning message when a binary file is opened.
202: By default,
203: .Nm
204: will refuse to open non-regular files.
1.12 jmc 205: .It Fl G | -HILITE-SEARCH
1.44 bentley 206: The
207: .Fl G
208: option suppresses all highlighting of strings found by search commands.
1.1 millert 209: .It Fl g | -hilite-search
210: Normally,
211: .Nm
1.44 bentley 212: will highlight all strings which match the last search command.
213: The
214: .Fl g
215: option changes this behavior to highlight only the particular string
1.1 millert 216: which was found by the last search command.
217: This can cause
218: .Nm
219: to run somewhat faster than the default.
1.44 bentley 220: .It Fl h Ar n | Fl -max-back-scroll Ns = Ns Ar n
1.1 millert 221: Specifies a maximum number of lines to scroll backward.
222: If it is necessary to scroll backward more than n lines,
223: the screen is repainted in a forward direction instead.
1.44 bentley 224: (If the terminal does not have the ability to scroll backward,
225: .Sq Fl h Ns 0
226: is implied.)
1.12 jmc 227: .It Fl I | -IGNORE-CASE
1.44 bentley 228: Like
229: .Fl i ,
230: but searches ignore case even if the pattern contains uppercase
1.12 jmc 231: letters.
1.1 millert 232: .It Fl i | -ignore-case
233: Causes searches to ignore case; that is,
234: uppercase and lowercase are considered identical.
235: This option is ignored if any uppercase letters appear in the search pattern;
236: in other words,
237: if a pattern contains uppercase letters, then that search does not ignore case.
1.12 jmc 238: .It Fl J | -status-column
239: Displays a status column at the left edge of the screen.
240: The status column shows the lines that matched the current search.
1.44 bentley 241: The status column is also used if the
242: .Fl w
243: or
244: .Fl W
245: option is in effect.
246: .It Fl j Ar n | Fl -jump-target Ns = Ns Ar n
247: Specifies a line on the screen where the
248: .Dq target
249: line is to be positioned.
1.23 shadchin 250: The target line is the line specified by any command to
251: search for a pattern, jump to a line number,
252: jump to a file percentage or jump to a tag.
253: The screen line may be specified by a number: the top line on the screen
1.1 millert 254: is 1, the next is 2, and so on.
255: The number may be negative to specify a line relative to the bottom
256: of the screen: the bottom line on the screen is -1, the second
257: to the bottom is -2, and so on.
1.23 shadchin 258: Alternately, the screen line may be specified as a fraction of the height
259: of the screen, starting with a decimal point: .5 is in the middle of the
260: screen, .3 is three tenths down from the first line, and so on.
261: If the line is specified as a fraction, the actual line number
262: is recalculated if the terminal window is resized, so that the
263: target line remains at the specified fraction of the screen height.
1.44 bentley 264: If any form of the
265: .Fl j
266: option is used,
1.23 shadchin 267: forward searches begin at the line immediately after the target line,
268: and backward searches begin at the target line,
1.44 bentley 269: unless changed by
270: .Fl a
271: or
272: .Fl A .
273: For example, if
274: .Sq Fl j Ns 4
275: is used, the target line is the fourth line on the screen,
276: so forward searches begin at the fifth line on the screen.
1.23 shadchin 277: .It Fl K | -quit-on-intr
278: Causes
279: .Nm
1.44 bentley 280: to exit immediately (with status 2) when an interrupt character (usually
281: .Ic ^C )
282: is typed.
1.23 shadchin 283: Normally, an interrupt character causes
284: .Nm
285: to stop whatever it is doing and return to its command prompt.
1.24 jmc 286: Note that use of this option makes it impossible to return to the
1.44 bentley 287: command prompt from the
288: .Ic F
289: command.
290: .It Fl k Ar keyfile | Fl -lesskey-file Ns = Ns Ar keyfile
1.1 millert 291: Causes
292: .Nm
293: to open and interpret the named file as a
294: .Xr lesskey 1
295: file.
1.44 bentley 296: Multiple
297: .Fl k
298: options may be specified.
1.36 jmc 299: If the
300: .Ev LESSKEY
301: or
302: .Ev LESSKEY_SYSTEM
303: environment variable is set, or if a lesskey file is found in a standard place
304: (see
305: .Sx KEY BINDINGS ) ,
306: it is also used as a lesskey file.
307: .It Fl L | -no-lessopen
308: Ignore the
309: .Ev LESSOPEN
310: environment variable (see the
311: .Sx INPUT PREPROCESSOR
312: section below).
313: This option can be set from within
314: .Nm less ,
315: but it will apply only to files opened subsequently, not to the
316: file which is currently open.
317: .It Fl M | -LONG-PROMPT
318: Causes
319: .Nm
320: to prompt even more verbosely than
1.39 jmc 321: .Xr more 1 .
1.36 jmc 322: .It Fl m | -long-prompt
323: Causes
324: .Nm
1.39 jmc 325: to prompt verbosely, like
326: .Xr more 1 ,
327: with the percent into the file.
1.36 jmc 328: By default,
329: .Nm
330: prompts with a colon.
331: .It Fl N | -LINE-NUMBERS
332: Causes a line number to be displayed at the beginning of each line in the
333: display.
334: .It Fl n | -line-numbers
335: Suppresses line numbers.
336: The default (to use line numbers) may cause
337: .Nm
338: to run more slowly in some cases, especially with a very large input file.
1.44 bentley 339: Suppressing line numbers with the
340: .Fl n
341: option will avoid this problem.
1.36 jmc 342: Using line numbers means: the line number will be displayed in the verbose
1.44 bentley 343: prompt and in the
344: .Ic =
345: command, and the
346: .Ic v
347: command will pass the current line
348: number to the editor (see also the discussion of
349: .Ev LESSEDIT
350: in
1.36 jmc 351: .Sx PROMPTS
352: below).
1.44 bentley 353: .It Fl O Ar logfile | Fl -LOG-FILE Ns = Ns Ar logfile
354: The
355: .Fl O
356: option is like
357: .Fl o ,
358: but it will overwrite an existing file without asking for confirmation.
1.36 jmc 359: .Pp
360: If no log file has been specified,
1.44 bentley 361: the
362: .Fl o
363: and
364: .Fl O
365: options can be used from within
1.36 jmc 366: .Nm
367: to specify a log file.
368: Without a file name, they will simply report the name of the log file.
1.44 bentley 369: The
370: .Ic s
371: command is equivalent to specifying
372: .Fl o
373: from within
374: .Nm .
375: .It Fl o Ar logfile | Fl -log-file Ns = Ns Ar logfile
1.36 jmc 376: Causes
377: .Nm
378: to copy its input to the named file as it is being viewed.
379: This applies only when the input file is a pipe, not an ordinary file.
380: If the file already exists,
381: .Nm
382: will ask for confirmation before overwriting it.
1.44 bentley 383: .It Fl P Ar prompt | Fl -prompt Ns = Ns Ar prompt
1.36 jmc 384: Provides a way to tailor the three prompt styles to your own preference.
385: This option would normally be put in the
386: .Ev LESS
387: environment variable, rather than being typed in with each
388: .Nm
389: command.
390: Such an option must either be the last option in the
391: .Ev LESS
392: variable, or be terminated by a dollar sign.
1.44 bentley 393: .Bl -item
394: .It
395: .Fl Ps Ar string
396: changes the default (short) prompt to
397: .Ar string .
398: .It
399: .Fl Pm
400: changes the medium
401: .Pq Fl m
402: prompt.
403: .It
404: .Fl PM
405: changes the long
406: .Pq Fl M
407: prompt.
408: .It
409: .Fl Ph
410: changes the prompt for the help screen.
411: .It
412: .Fl P=
413: changes the message printed by the
414: .Ic =
415: command.
416: .It
417: .Fl Pw
418: changes the message printed while waiting for data (in the
419: .Ic F
420: command).
421: .El
1.36 jmc 422: All prompt strings consist of a sequence of letters and special escape
423: sequences.
424: See the section on
425: .Sx PROMPTS
426: for more details.
1.44 bentley 427: .It Fl p Ar pattern | Fl -pattern Ns = Ns Ar pattern
428: The
429: .Fl p
430: option on the command line is equivalent to specifying
431: .Cm +/ Ns Ar pattern ;
1.36 jmc 432: that is, it tells
433: .Nm
434: to start at the first occurrence of pattern in the file.
435: .It Fl Q | -QUIET | -SILENT
1.44 bentley 436: Causes totally quiet operation: the terminal bell is never rung.
1.36 jmc 437: .It Fl q | -quiet | -silent
1.44 bentley 438: Causes moderately quiet operation:
1.36 jmc 439: the terminal bell is not rung if an attempt is made to scroll past the end
440: of the file or before the beginning of the file.
1.44 bentley 441: If the terminal has a visual bell, it is used instead.
1.36 jmc 442: The bell will be rung on certain other errors,
443: such as typing an invalid character.
444: The default is to ring the terminal bell in all such cases.
445: .It Fl R | -RAW-CONTROL-CHARS
1.44 bentley 446: Like
447: .Fl r ,
448: but only ANSI color escape sequences are output in raw form.
449: Unlike
450: .Fl r ,
451: the screen appearance is maintained correctly in most cases.
452: ANSI color escape sequences are sequences of the form:
1.36 jmc 453: .Pp
454: .Dl ESC \&[ ... m
455: .Pp
1.44 bentley 456: where the
457: .Dq ...
458: is zero or more color specification characters.
1.36 jmc 459: For the purpose of keeping track of screen appearance,
460: ANSI color escape sequences are assumed to not move the cursor.
461: You can make
462: .Nm
1.44 bentley 463: think that characters other than
464: .Sq m
465: can end ANSI color escape sequences by setting the environment variable
1.36 jmc 466: .Ev LESSANSIENDCHARS
467: to the list of characters which can end a color escape sequence.
468: And you can make
469: .Nm
470: think that characters other than the standard ones may appear between
1.44 bentley 471: the
472: .Cm ESC
473: and the
474: .Cm m
475: by setting the environment variable
1.36 jmc 476: .Ev LESSANSIMIDCHARS
477: to the list of characters which can appear.
478: .It Fl r | -raw-control-chars
1.44 bentley 479: Causes raw control characters to be displayed.
1.36 jmc 480: The default is to display control characters using the caret notation;
1.44 bentley 481: for example, a control-A (octal 001) is displayed as
482: .Sq ^A .
483: .Sy Warning :
484: when the
485: .Fl r
486: option is used,
1.36 jmc 487: .Nm
488: cannot keep track of the actual appearance of the screen
489: (since this depends on how the screen responds to
490: each type of control character).
491: Thus, various display problems may result,
492: such as long lines being split in the wrong place.
493: .It Fl S | -chop-long-lines
1.55 schwarze 494: Display only the beginning of lines that exceed the screen width.
495: The remainder can be shown by scrolling horizontally.
1.36 jmc 496: The default is to wrap long lines; that is, display the remainder
497: on the next line.
498: .It Fl s | -squeeze-blank-lines
499: Causes consecutive blank lines to be squeezed into a single blank line.
1.44 bentley 500: .It Fl T Ar tagsfile | Fl -tag-file Ns = Ns Ar tagsfile
501: Specifies a tags file to be used instead of
502: .Pa tags .
1.36 jmc 503: .It Xo
504: .Fl t Ar tag |
505: .Fl -tag Ns = Ns Ar tag
506: .Xc
1.44 bentley 507: The
508: .Fl t
509: option, followed immediately by a
510: .Ar tag ,
1.36 jmc 511: will edit the file containing that tag.
512: For this to work, tag information must be available;
1.44 bentley 513: for example, there may be a file in the current directory called
514: .Pa tags ,
1.36 jmc 515: which was previously built by
516: .Xr ctags 1
517: or an equivalent command.
1.44 bentley 518: The
519: .Fl t
520: option may also be specified from within
1.36 jmc 521: .Nm
1.44 bentley 522: (using the
523: .Ic -
524: command) as a way of examining a new file.
525: The command
526: .Ic :t
527: is equivalent to specifying
528: .Fl t
529: from within
530: .Nm .
1.36 jmc 531: .It Fl U | -UNDERLINE-SPECIAL
532: Causes backspaces, tabs and carriage returns to be
533: treated as control characters;
1.44 bentley 534: that is, they are handled as specified by the
535: .Fl r
536: option.
1.36 jmc 537: .Pp
1.44 bentley 538: By default, if neither
539: .Fl u
540: nor
541: .Fl U
542: is given, backspaces which appear adjacent
1.36 jmc 543: to an underscore character are treated specially:
544: the underlined text is displayed
545: using the terminal's hardware underlining capability.
546: Also, backspaces which appear between two identical characters
547: are treated specially:
548: the overstruck text is printed
549: using the terminal's hardware boldface capability.
550: Other backspaces are deleted, along with the preceding character.
551: Carriage returns immediately followed by a newline are deleted.
1.44 bentley 552: Other carriage returns are handled as specified by the
553: .Fl r
554: option.
1.36 jmc 555: Text which is overstruck or underlined can be searched for
1.44 bentley 556: if neither
557: .Fl u
558: nor
559: .Fl U
560: is in effect.
1.36 jmc 561: .It Fl u | -underline-special
562: Causes backspaces and carriage returns to be treated as printable characters;
563: that is, they are sent to the terminal when they appear in the input.
564: .It Fl V | -version
565: Displays the version number of
1.44 bentley 566: .Nm .
1.36 jmc 567: .It Fl W | -HILITE-UNREAD
1.44 bentley 568: Like
569: .Fl w ,
570: but temporarily highlights the first new line after any
1.36 jmc 571: forward movement command larger than one line.
572: .It Fl w | -hilite-unread
1.44 bentley 573: Temporarily highlights the first new line after a forward movement
1.36 jmc 574: of a full page.
1.44 bentley 575: The first new line is the line immediately following the line previously
1.36 jmc 576: at the bottom of the screen.
1.44 bentley 577: Also highlights the target line after a
578: .Ic g
579: or
580: .Ic p
581: command.
1.36 jmc 582: The highlight is removed at the next command which causes movement.
1.44 bentley 583: The entire line is highlighted, unless the
584: .Fl J
585: option is in effect,
1.36 jmc 586: in which case only the status column is highlighted.
587: .It Fl X | -no-init
588: Disables sending the termcap initialization and deinitialization strings
589: to the terminal.
590: This is sometimes desirable if the deinitialization string does
591: something unnecessary, like clearing the screen.
592: .It Xo
1.44 bentley 593: .Fl x Ar n , Ns Ar ... |
594: .Fl -tabs Ns = Ns Ar n , Ns Ar ...
1.36 jmc 595: .Xc
596: Sets tab stops.
1.44 bentley 597: If only one
598: .Ar n
599: is specified, tab stops are set at multiples of
600: .Ar n .
1.36 jmc 601: If multiple values separated by commas are specified, tab stops are set at
602: those positions, and then continue with the same spacing as the last two.
1.44 bentley 603: For example,
604: .Sq Fl x Ns 9,17
605: will set tabs at positions 9, 17, 25, 33, etc.
606: The default for
607: .Ar n
608: is 8.
609: .It Fl y Ar n | Fl -max-forw-scroll Ns = Ns Ar n
1.36 jmc 610: Specifies a maximum number of lines to scroll forward.
611: If it is necessary to scroll forward more than n lines,
612: the screen is repainted instead.
1.44 bentley 613: The
614: .Fl c
615: or
616: .Fl C
617: option may be used to repaint from the top of the screen if desired.
1.36 jmc 618: By default, any forward movement causes scrolling.
1.44 bentley 619: .It Fl z Ar n | Fl -window Ns = Ns Ar n
620: Changes the default scrolling window size to
621: .Ar n
622: lines.
1.36 jmc 623: The default is one screenful.
1.44 bentley 624: The
625: .Ic z
626: and
627: .Ic w
628: commands can also be used to change the window size.
629: The
630: .Cm z
631: may be omitted for compatibility with some versions of
1.39 jmc 632: .Xr more 1 .
1.36 jmc 633: If the number
634: .Ar n
635: is negative, it indicates
636: .Ar n
637: lines less than the current screen size.
1.44 bentley 638: For example, if the screen is 24 lines,
639: .Fl z Ns -4
640: sets the scrolling window to 20 lines.
1.36 jmc 641: If the screen is resized to 40 lines,
642: the scrolling window automatically changes to 36 lines.
643: .It Fl -follow-name
1.44 bentley 644: Normally, if the input file is renamed while an
645: .Ic F
646: command is executing,
1.1 millert 647: .Nm
1.36 jmc 648: will continue to display the contents of the original file despite
649: its name change.
1.44 bentley 650: If
651: .Fl -follow-name
652: is specified, during an
653: .Ic F
654: command
1.1 millert 655: .Nm
1.36 jmc 656: will periodically attempt to reopen the file by name.
657: If the reopen succeeds and the file is a different file from the original
658: (which means that a new file has been created
659: with the same name as the original (now renamed) file),
1.1 millert 660: .Nm
1.36 jmc 661: will display the contents of that new file.
662: .It Fl -no-keypad
663: Disables sending the keypad initialization and deinitialization strings
664: to the terminal.
665: This is sometimes useful if the keypad strings make the numeric
666: keypad behave in an undesirable manner.
667: .It Fl -use-backslash
668: This option changes the interpretations of options which follow this one.
1.44 bentley 669: After the
670: .Fl -use-backslash
671: option, any backslash in an option string is
1.36 jmc 672: removed and the following character is taken literally.
673: This allows a dollar sign to be included in option strings.
1.44 bentley 674: .It Fl \&" Ar cc | Fl -quotes Ns = Ns Ar cc
1.36 jmc 675: Changes the filename quoting character.
676: This may be necessary if you are trying to name a file
677: which contains both spaces and quote characters.
1.44 bentley 678: If
679: .Ar cc
680: is a single character, this changes the quote character to that character.
1.36 jmc 681: Filenames containing a space should then be surrounded by that character
682: rather than by double quotes.
1.44 bentley 683: If
684: .Ar cc
685: consists of two characters, this changes the open quote to the first character,
1.36 jmc 686: and the close quote to the second character.
687: Filenames containing a space should then be preceded by the open quote
688: character and followed by the close quote character.
689: Note that even after the quote characters are changed, this option
1.44 bentley 690: remains
691: .Fl \&"
692: (a dash followed by a double quote).
1.36 jmc 693: .It Fl ~ | -tilde
694: Normally lines after end of file are displayed as a single tilde (~).
695: This option causes lines after end of file to be displayed as blank lines.
1.53 schwarze 696: .It Fl # Ar n | Fl -shift Ns = Ns Ar n
697: Specifies the default number
698: .Ar n
699: of positions to scroll horizontally
1.36 jmc 700: in the RIGHTARROW and LEFTARROW commands.
1.53 schwarze 701: If
702: .Ar n
703: is zero, it sets the default number of
1.36 jmc 704: positions to one half of the screen width.
705: Alternately, the number may be specified as a fraction of the width
706: of the screen, starting with a decimal point: .5 is half of the
707: screen width, .3 is three tenths of the screen width, and so on.
708: If the number is specified as a fraction, the actual number of
709: scroll positions is recalculated if the terminal window is resized,
710: so that the actual scroll remains at the specified fraction
711: of the screen width.
712: .It Fl -
1.44 bentley 713: A command line argument of
714: .Fl -
715: marks the end of option arguments.
1.36 jmc 716: Any arguments following this are interpreted as filenames.
1.44 bentley 717: This can be useful when viewing a file whose name begins with a
718: .Sq -
719: or
720: .Sq + .
1.36 jmc 721: .It Cm +
722: If a command line option begins with +,
723: the remainder of that option is taken to be an initial command to
1.44 bentley 724: .Nm .
725: For example,
726: .Cm +G
727: tells
1.36 jmc 728: .Nm
729: to start at the end of the file rather than the beginning,
1.44 bentley 730: and
731: .Cm +/xyz
732: tells it to start at the first occurrence of
733: .Dq xyz
734: in the file.
735: As a special case,
736: .Cm + Ns Ar number
737: acts like
738: .Cm + Ns Ar number Ns g ;
1.36 jmc 739: that is, it starts the display at the specified line number
1.44 bentley 740: (however, see the caveat under the
741: .Ic g
742: command below).
743: If the option starts with
744: .Cm ++ ,
745: the initial command applies to every file being viewed, not just the first one.
746: The
747: .Cm +
748: command described previously
1.36 jmc 749: may also be used to set (or change) an initial command for every file.
750: .El
751: .Sh COMMANDS
1.56 ! jmc 752: Commands are based on both traditional
! 753: .Xr more 1
! 754: and
! 755: .Xr vi 1 .
! 756: Commands may be preceded by a decimal number,
! 757: called
! 758: .Ar N
! 759: in the descriptions below.
1.36 jmc 760: In the following descriptions, ^X means control-X.
761: ESC stands for the ESCAPE key; for example ESC-v means the
762: two character sequence "ESCAPE", then "v".
763: .Bl -tag -width XXXX
764: .It Ic h | H
765: Help: display a summary of these commands.
766: If you forget all the other commands, remember this one.
767: .It Ic SPACE | ^V | f | ^F
1.44 bentley 768: Scroll forward N lines, default one window (see option
769: .Fl z
770: above).
1.36 jmc 771: If N is more than the screen size, only the final screenful is displayed.
772: Warning: some systems use ^V as a special literalization character.
773: .It Ic z
774: Like SPACE, but if N is specified, it becomes the new window size.
775: .It Ic ESC-SPACE
776: Like SPACE, but scrolls a full screenful, even if it reaches
777: end-of-file in the process.
778: .It Ic ENTER | RETURN | ^N | e | ^E | j | ^J
779: Scroll forward N lines, default 1.
780: The entire N lines are displayed, even if N is more than the screen size.
781: .It Ic d | ^D
782: Scroll forward N lines, default one half of the screen size.
783: If N is specified, it becomes the new default for subsequent d and u commands.
784: .It Ic b | ^B | ESC-v
1.44 bentley 785: Scroll backward N lines, default one window (see option
786: .Fl z
787: above).
1.36 jmc 788: If N is more than the screen size, only the final screenful is displayed.
789: .It Ic w
790: Like ESC-v, but if N is specified, it becomes the new window size.
791: .It Ic y | ^Y | ^P | k | ^K
792: Scroll backward N lines, default 1.
793: The entire N lines are displayed, even if N is more than the screen size.
794: Warning: some systems use ^Y as a special job control character.
795: .It Ic u | ^U
796: Scroll backward N lines, default one half of the screen size.
797: If N is specified, it becomes the new default for subsequent d and u commands.
798: .It Ic ESC-) | RIGHTARROW
799: Scroll horizontally right N characters, default half the screen width
1.44 bentley 800: (see the
801: .Fl #
802: option).
1.36 jmc 803: If a number N is specified, it becomes the default for future
804: RIGHTARROW and LEFTARROW commands.
1.44 bentley 805: While the text is scrolled, it acts as though the
806: .Fl S
807: option (chop lines) were in effect.
1.36 jmc 808: .It Ic ESC-( | LEFTARROW
809: Scroll horizontally left N
1.44 bentley 810: characters, default half the screen width (see the
811: .Fl #
812: option).
1.36 jmc 813: If a number N is specified, it becomes the default for future
814: RIGHTARROW and LEFTARROW commands.
815: .It Ic r | ^R | ^L
816: Repaint the screen.
817: .It Ic R
818: Repaint the screen, discarding any buffered input.
819: Useful if the file is changing while it is being viewed.
820: .It Ic F
821: Scroll forward, and keep trying to read when the end of file is reached.
822: Normally this command would be used when already at the end of the file.
823: It is a way to monitor the tail of a file which is growing
824: while it is being viewed.
825: (The behavior is similar to the "tail -f" command.)
826: .It Ic ESC-F
827: Like F, but as soon as a line is found which matches
828: the last search pattern, the terminal bell is rung
829: and forward scrolling stops.
830: .It Ic g | < | ESC-<
831: Go to line N in the file, default 1 (beginning of file).
832: (Warning: this may be slow if N is large.)
833: .It Ic G | > | ESC->
834: Go to line N in the file, default the end of the file.
835: (Warning: this may be slow if N is large,
836: or if N is not specified and standard input, rather than a file,
837: is being read.)
838: .It Ic p | %
839: Go to a position N percent into the file.
840: N should be between 0 and 100, and may contain a decimal point.
841: .It Ic P
842: Go to the line containing byte offset N in the file.
843: .It Ic {
844: If a left curly bracket appears in the top line displayed
845: on the screen, the { command will go to the matching right curly bracket.
846: The matching right curly bracket is positioned on the bottom
847: line of the screen.
848: If there is more than one left curly bracket on the top line, a number N
849: may be used to specify the N-th bracket on the line.
850: .It Ic }
851: If a right curly bracket appears in the bottom line displayed on the screen,
852: the } command will go to the matching left curly bracket.
853: The matching left curly bracket is positioned on the top
854: line of the screen.
855: If there is more than one right curly bracket on the top line,
856: a number N may be used to specify the N-th bracket on the line.
857: .It Ic \&(
858: Like {, but applies to parentheses rather than curly brackets.
859: .It Ic \&)
860: Like }, but applies to parentheses rather than curly brackets.
861: .It Ic \&[
862: Like {, but applies to square brackets rather than curly brackets.
863: .It Ic \&]
864: Like }, but applies to square brackets rather than curly brackets.
865: .It Ic ESC-^F
866: Followed by two characters, acts like {,
867: but uses the two characters as open and close brackets, respectively.
868: For example, "ESC ^F < >" could be used to
869: go forward to the > which matches the < in the top displayed line.
870: .It Ic ESC-^B
871: Followed by two characters, acts like },
872: but uses the two characters as open and close brackets, respectively.
873: For example, "ESC ^B < >" could be used to
874: go backward to the < which matches the > in the bottom displayed line.
875: .It Ic m
876: Followed by any lowercase letter, marks the current position with that letter.
877: .It Ic '
878: (Single quote.)
879: Followed by any lowercase letter, returns to the position which
880: was previously marked with that letter.
881: Followed by another single quote, returns to the position at
882: which the last "large" movement command was executed.
883: Followed by a ^ or $, jumps to the beginning or end of the file respectively.
884: Marks are preserved when a new file is examined,
885: so the ' command can be used to switch between input files.
886: .It Ic ^X^X
887: Same as single quote.
888: .It Ic /pattern
889: Search forward in the file for the N-th line containing the pattern.
890: N defaults to 1.
891: The pattern is a regular expression, as recognized by
892: the regular expression library supplied by your system.
893: The search starts at the first line displayed
1.44 bentley 894: (but see the
895: .Fl a
896: and
897: .Fl j
898: options, which change this).
1.1 millert 899: .Pp
1.36 jmc 900: Certain characters are special if entered at the beginning of the pattern;
901: they modify the type of search rather than become part of the pattern:
902: .Bl -tag -width Ds
903: .It Ic ^N | \&!
904: Search for lines which do NOT match the pattern.
905: .It Ic ^E | *
906: Search multiple files.
907: That is, if the search reaches the END of the current file
908: without finding a match,
909: the search continues in the next file in the command line list.
910: .It Ic ^F | @
911: Begin the search at the first line of the FIRST file
912: in the command line list,
913: regardless of what is currently displayed on the screen
1.44 bentley 914: or the settings of the
915: .Fl a
916: or
917: .Fl j
918: options.
1.36 jmc 919: .It Ic ^K
920: Highlight any text which matches the pattern on the current screen,
921: but don't move to the first match (KEEP current position).
922: .It Ic ^R
923: Don't interpret regular expression metacharacters;
924: that is, do a simple textual comparison.
925: .El
926: .It Ic ?pattern
927: Search backward in the file for the N-th line containing the pattern.
928: The search starts at the line immediately before the top line displayed.
1.1 millert 929: .Pp
1.36 jmc 930: Certain characters are special, as in the / command:
931: .Bl -tag -width Ds
932: .It Ic ^N | \&!
933: Search for lines which do NOT match the pattern.
934: .It Ic ^E | *
935: Search multiple files.
936: That is, if the search reaches the beginning of the current file
937: without finding a match,
938: the search continues in the previous file in the command line list.
939: .It Ic ^F | @
940: Begin the search at the last line of the last file
941: in the command line list,
942: regardless of what is currently displayed on the screen
1.44 bentley 943: or the settings of the
944: .Fl a
945: or
946: .Fl j
947: options.
1.36 jmc 948: .It Ic ^K
949: As in forward searches.
950: .It Ic ^R
951: As in forward searches.
952: .El
953: .It Ic ESC-/pattern
954: Same as "/*".
955: .It Ic ESC-?pattern
956: Same as "?*".
957: .It Ic n
958: Repeat previous search, for N-th line containing the last pattern.
959: If the previous search was modified by ^N, the search is made for the
960: N-th line NOT containing the pattern.
961: If the previous search was modified by ^E, the search continues
962: in the next (or previous) file if not satisfied in the current file.
963: If the previous search was modified by ^R, the search is done
964: without using regular expressions.
965: There is no effect if the previous search was modified by ^F or ^K.
966: .It Ic N
967: Repeat previous search, but in the reverse direction.
968: .It Ic ESC-n
969: Repeat previous search, but crossing file boundaries.
970: The effect is as if the previous search were modified by *.
971: .It Ic ESC-N
972: Repeat previous search, but in the reverse direction
973: and crossing file boundaries.
974: .It Ic ESC-u
975: Undo search highlighting.
976: Turn off highlighting of strings matching the current search pattern.
977: If highlighting is already off because of a previous ESC-u command,
978: turn highlighting back on.
979: Any search command will also turn highlighting back on.
1.44 bentley 980: (Highlighting can also be disabled by toggling the
981: .Fl G
982: option;
1.36 jmc 983: in that case search commands do not turn highlighting back on.)
984: .It Ic &pattern
985: Display only lines which match the pattern;
986: lines which do not match the pattern are not displayed.
987: If pattern is empty (if you type & immediately followed by ENTER),
988: any filtering is turned off, and all lines are displayed.
989: While filtering is in effect, an ampersand is displayed at the
990: beginning of the prompt,
991: as a reminder that some lines in the file may be hidden.
1.1 millert 992: .Pp
1.36 jmc 993: Certain characters are special as in the / command:
994: .Bl -tag -width Ds
995: .It Ic ^N | !
996: Display only lines which do NOT match the pattern.
997: .It Ic ^R
998: Don't interpret regular expression metacharacters;
999: that is, do a simple textual comparison.
1000: .El
1001: .It Ic :e Op Ar filename
1002: Examine a new file.
1003: If the filename is missing, the "current" file (see the :n and :p commands
1004: below) from the list of files in the command line is re-examined.
1005: A percent sign (%) in the filename is replaced by the name of the
1006: current file.
1007: A pound sign (#) is replaced by the name of the previously examined file.
1008: However, two consecutive percent signs are simply
1009: replaced with a single percent sign.
1010: This allows you to enter a filename that contains a percent sign
1011: in the name.
1012: Similarly, two consecutive pound signs are replaced with a single pound sign.
1013: The filename is inserted into the command line list of files
1014: so that it can be seen by subsequent :n and :p commands.
1015: If the filename consists of several files, they are all inserted into
1016: the list of files and the first one is examined.
1017: If the filename contains one or more spaces,
1018: the entire filename should be enclosed in double quotes
1.44 bentley 1019: (also see the
1020: .Fl \&"
1021: option).
1.36 jmc 1022: .It Ic ^X^V | E
1023: Same as :e.
1024: Warning: some systems use ^V as a special literalization character.
1025: On such systems, you may not be able to use ^V.
1026: .It Ic :n
1027: Examine the next file (from the list of files given in the command line).
1028: If a number N is specified, the N-th next file is examined.
1029: .It Ic :p
1030: Examine the previous file in the command line list.
1031: If a number N is specified, the N-th previous file is examined.
1032: .It Ic :t
1033: Go to the specified tag.
1034: .It Ic :x
1035: Examine the first file in the command line list.
1036: If a number N is specified, the N-th file in the list is examined.
1037: .It Ic :d
1038: Remove the current file from the list of files.
1039: .It Ic t
1040: Go to the next tag, if there were more than one matches for the current tag.
1.44 bentley 1041: See the
1042: .Fl t
1043: option for more details about tags.
1.36 jmc 1044: .It Ic T
1045: Go to the previous tag, if there were more than one matches for the current tag.
1046: .It Ic = | ^G | :f
1047: Prints some information about the file being viewed, including its name
1048: and the line number and byte offset of the bottom line being displayed.
1049: If possible, it also prints the length of the file,
1050: the number of lines in the file
1051: and the percent of the file above the last displayed line.
1052: .It Ic \-
1053: Followed by one of the command line option letters (see
1.44 bentley 1054: .Sx DESCRIPTION
1055: above),
1.36 jmc 1056: this will change the setting of that option
1057: and print a message describing the new setting.
1058: If a ^P (CONTROL-P) is entered immediately after the dash,
1059: the setting of the option is changed but no message is printed.
1.44 bentley 1060: If the option letter has a numeric value (such as
1061: .Fl b
1062: or
1063: .Fl h ) ,
1064: or a string value (such as
1065: .Fl P
1066: or
1067: .Fl t ) ,
1.36 jmc 1068: a new value may be entered after the option letter.
1069: If no new value is entered, a message describing
1070: the current setting is printed and nothing is changed.
1071: .It Ic \-\-
1072: Like the \- command, but takes a long option name (see
1.44 bentley 1073: .Sx DESCRIPTION
1074: above)
1.36 jmc 1075: rather than a single option letter.
1076: You must press ENTER or RETURN after typing the option name.
1077: A ^P immediately after the second dash suppresses printing of a
1078: message describing the new setting, as in the \- command.
1079: .It Ic \-+
1080: Followed by one of the command line option letters this will reset the
1081: option to its default setting and print a message describing the new setting.
1.44 bentley 1082: (The "\-+X" command does the same thing as
1083: .Sq Fl + Ns X
1084: on the command line.)
1.36 jmc 1085: This does not work for string-valued options.
1086: .It Ic \-\-+
1087: Like the \-+ command, but takes a long option name
1088: rather than a single option letter.
1089: .It Ic \-!
1090: Followed by one of the command line option letters, this will reset the
1091: option to the "opposite" of its default setting and print a message
1092: describing the new setting.
1093: This does not work for numeric or string-valued options.
1094: .It Ic \-\-!
1095: Like the \-! command, but takes a long option name
1096: rather than a single option letter.
1097: .It Ic _
1098: (Underscore.)
1099: Followed by one of the command line option letters,
1100: this will print a message describing the current setting of that option.
1101: The setting of the option is not changed.
1102: .It Ic __
1103: (Double underscore.)
1104: Like the _ (underscore) command, but takes a long option name
1105: rather than a single option letter.
1106: You must press ENTER or RETURN after typing the option name.
1107: .It Ic +cmd
1108: Causes the specified cmd to be executed each time a new file is examined.
1109: For example, +G causes
1.23 shadchin 1110: .Nm
1.36 jmc 1111: to initially display each file starting at the end rather than the beginning.
1112: .It Ic V
1113: Prints the version number of
1.12 jmc 1114: .Nm
1.36 jmc 1115: being run.
1116: .It Ic q | Q | :q | :Q | ZZ
1117: Exits
1.1 millert 1118: .Nm less .
1.36 jmc 1119: .El
1.1 millert 1120: .Pp
1.36 jmc 1121: The following
1122: four
1123: commands may or may not be valid, depending on your particular installation.
1124: .Bl -tag -width XXXX
1125: .It Ic v
1126: Invokes an editor to edit the current file being viewed.
1127: The editor is taken from the environment variable
1128: .Ev VISUAL ,
1129: if defined,
1130: or
1131: .Ev EDITOR
1132: if
1133: .Ev VISUAL
1134: is not defined,
1135: or defaults to "vi" if neither
1136: .Ev VISUAL
1137: nor
1138: .Ev EDITOR
1139: is defined.
1140: See also the discussion of LESSEDIT under the section on
1141: .Sx PROMPTS
1142: below.
1143: .It Ic | <m> Ar shell-command
1144: <m> represents any mark letter.
1145: Pipes a section of the input file to the given shell command.
1146: The section of the file to be piped is between the first line on
1147: the current screen and the position marked by the letter.
1148: <m> may also be ^ or $ to indicate beginning or end of file respectively.
1149: If <m> is . or newline, the current screen is piped.
1150: .It Ic s Ar filename
1151: Save the input to a file.
1152: This only works if the input is a pipe, not an ordinary file.
1.1 millert 1153: .El
1154: .Sh LINE EDITING
1155: When entering command line at the bottom of the screen
1156: (for example, a filename for the :e command,
1157: or the pattern for a search command),
1158: certain keys can be used to manipulate the command line.
1159: Most commands have an alternate form in [ brackets ] which can be used if
1160: a key does not exist on a particular keyboard.
1161: Any of these special keys may be entered literally by preceding
1162: it with the "literal" character, either ^V or ^A.
1163: A backslash itself may also be entered literally by entering two backslashes.
1164: .Bl -tag -width Ds
1165: .It LEFTARROW [ ESC-h ]
1166: Move the cursor one space to the left.
1167: .It RIGHTARROW [ ESC-l ]
1168: Move the cursor one space to the right.
1169: .It ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
1170: (That is, CONTROL and LEFTARROW simultaneously.)
1171: Move the cursor one word to the left.
1172: .It ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
1173: (That is, CONTROL and RIGHTARROW simultaneously.)
1174: Move the cursor one word to the right.
1175: .It HOME [ ESC-0 ]
1176: Move the cursor to the beginning of the line.
1177: .It END [ ESC-$ ]
1178: Move the cursor to the end of the line.
1179: .It BACKSPACE
1180: Delete the character to the left of the cursor,
1181: or cancel the command if the command line is empty.
1182: .It DELETE or [ ESC-x ]
1183: Delete the character under the cursor.
1184: .It ^BACKSPACE [ ESC-BACKSPACE ]
1185: (That is, CONTROL and BACKSPACE simultaneously.)
1186: Delete the word to the left of the cursor.
1187: .It ^DELETE [ ESC-X or ESC-DELETE ]
1188: (That is, CONTROL and DELETE simultaneously.)
1189: Delete the word under the cursor.
1190: .It UPARROW [ ESC-k ]
1191: Retrieve the previous command line.
1.32 shadchin 1192: If you first enter some text and then press UPARROW,
1193: it will retrieve the previous command which begins with that text.
1.1 millert 1194: .It DOWNARROW [ ESC-j ]
1195: Retrieve the next command line.
1.32 shadchin 1196: If you first enter some text and then press DOWNARROW,
1197: it will retrieve the next command which begins with that text.
1.1 millert 1198: .It TAB
1199: Complete the partial filename to the left of the cursor.
1200: If it matches more than one filename, the first match
1201: is entered into the command line.
1202: Repeated TABs will cycle through the other matching filenames.
1203: If the completed filename is a directory, a "/" is appended to the filename.
1204: The environment variable
1205: .Ev LESSSEPARATOR
1206: can be used to specify a different character to append to a directory name.
1207: .It BACKTAB [ ESC-TAB ]
1208: Like TAB, but cycles in the reverse direction through the matching filenames.
1209: .It ^L
1210: Complete the partial filename to the left of the cursor.
1211: If it matches more than one filename, all matches are entered into
1212: the command line (if they fit).
1213: .It ^U
1214: Delete the entire command line,
1215: or cancel the command if the command line is empty.
1216: If you have changed your line-kill character to something
1217: other than ^U, that character is used instead of ^U.
1.23 shadchin 1218: .It "^G"
1219: Delete the entire command line and return to the main prompt.
1.1 millert 1220: .El
1221: .Sh KEY BINDINGS
1222: You may define your own
1223: .Nm
1224: commands by using the program
1225: .Xr lesskey 1
1226: to create a lesskey file.
1227: This file specifies a set of command keys and an action
1228: associated with each key.
1229: You may also use lesskey
1230: to change the line-editing keys (see
1231: .Sx LINE EDITING ) ,
1232: and to set environment variables.
1233: If the environment variable
1234: .Ev LESSKEY
1235: is set,
1236: .Nm
1237: uses that as the name of the lesskey file.
1238: Otherwise,
1239: .Nm
1240: looks for a lesskey file called "$HOME/.less".
1241: See the
1242: .Xr lesskey 1
1243: manual page for more details.
1244: .Pp
1245: A system-wide lesskey file may also be set up to provide key bindings.
1246: If a key is defined in both a local lesskey file and in the
1247: system-wide file, key bindings in the local file take precedence over
1248: those in the system-wide file.
1249: If the environment variable
1250: .Ev LESSKEY_SYSTEM
1251: is set,
1252: .Nm
1253: uses that as the name of the system-wide lesskey file.
1254: Otherwise,
1255: .Nm
1256: looks in a standard place for the system-wide lesskey file:
1257: On
1258: .Ox ,
1259: the system-wide lesskey file is
1260: .Pa /etc/sysless .
1261: .Sh INPUT PREPROCESSOR
1262: You may define an "input preprocessor" for
1263: .Nm less .
1264: Before
1265: .Nm less
1266: opens a file, it first gives your input preprocessor a chance to modify the
1267: way the contents of the file are displayed.
1268: An input preprocessor is simply an executable program (or shell script),
1269: which writes the contents of the file to a different file,
1270: called the replacement file.
1271: The contents of the replacement file are then displayed
1272: in place of the contents of the original file.
1273: However, it will appear to the user as if the original file is opened;
1274: that is,
1275: .Nm less
1276: will display the original filename as the name of the current file.
1277: .Pp
1278: An input preprocessor receives one command line argument, the original filename,
1279: as entered by the user.
1280: It should create the replacement file, and when finished
1281: print the name of the replacement file to its standard output.
1282: If the input preprocessor does not output a replacement filename,
1283: .Nm
1284: uses the original file, as normal.
1285: The input preprocessor is not called when viewing standard input.
1286: To set up an input preprocessor, set the
1287: .Ev LESSOPEN
1288: environment variable to a command line which will invoke your
1289: input preprocessor.
1290: This command line should include one occurrence of the string "%s",
1291: which will be replaced by the filename
1292: when the input preprocessor command is invoked.
1293: .Pp
1294: When
1295: .Nm
1296: closes a file opened in such a way, it will call another program,
1297: called the input postprocessor,
1298: which may perform any desired clean-up action (such as deleting the
1299: replacement file created by
1300: .Ev LESSOPEN ) .
1301: This program receives two command line arguments, the original filename
1302: as entered by the user, and the name of the replacement file.
1303: To set up an input postprocessor, set the
1304: .Ev LESSCLOSE
1305: environment variable to a command line which will invoke your
1306: input postprocessor.
1307: It may include two occurrences of the string "%s";
1308: the first is replaced with the original name of the file and the second
1309: with the name of the replacement file, which was output by
1310: .Ev LESSOPEN .
1311: .Pp
1312: For example, these two scripts will allow you
1313: to keep files in compressed format, but still let
1314: .Nm
1315: view them directly:
1316: .Pp
1317: lessopen.sh:
1318: .Bd -literal -offset indent
1319: #! /bin/sh
1320: case "$1" in
1321: *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
1322: if [ -s /tmp/less.$$ ]; then
1323: echo /tmp/less.$$
1324: else
1325: rm -f /tmp/less.$$
1326: fi
1327: ;;
1328: esac
1329: .Ed
1330: .Pp
1331: lessclose.sh:
1332: .Bd -literal -offset indent
1333: #! /bin/sh
1334: rm $2
1335: .Ed
1336: .Pp
1337: To use these scripts, put them both where they can be executed and
1338: set LESSOPEN="lessopen.sh\ %s", and LESSCLOSE="lessclose.sh\ %s\ %s".
1339: More complex LESSOPEN and LESSCLOSE scripts may be written
1340: to accept other types of compressed files, and so on.
1341: .Pp
1342: It is also possible to set up an input preprocessor to
1343: pipe the file data directly to
1344: .Nm less ,
1345: rather than putting the data into a replacement file.
1346: This avoids the need to decompress the entire file before starting to view it.
1347: An input preprocessor that works this way is called an input pipe.
1348: An input pipe, instead of writing the name of a replacement file on
1349: its standard output,
1350: writes the entire contents of the replacement file on its standard output.
1351: If the input pipe does not write any characters on its standard output,
1352: then there is no replacement file and
1353: .Nm
1354: uses the original file, as normal.
1355: To use an input pipe, make the first character in the
1356: .Ev LESSOPEN
1357: environment variable a vertical bar (|) to signify that the
1358: input preprocessor is an input pipe.
1359: .Pp
1360: For example, this script will work like the previous example scripts:
1361: .Pp
1362: lesspipe.sh:
1363: .Bd -literal -offset indent
1364: #! /bin/sh
1365: case "$1" in
1366: *.Z) uncompress -c $1 2>/dev/null
1.32 shadchin 1367: *) exit 1
1.1 millert 1368: ;;
1369: esac
1.32 shadchin 1370: exit $?
1.1 millert 1371: .Ed
1372: .Pp
1373: To use this script, put it where it can be executed and set
1374: LESSOPEN="|lesspipe.sh %s".
1.32 shadchin 1375: .Pp
1376: Note that a preprocessor cannot output an empty file, since that
1377: is interpreted as meaning there is no replacement, and
1378: the original file is used.
1379: To avoid this, if
1380: .Ev LESSOPEN
1381: starts with two vertical bars,
1382: the exit status of the script becomes meaningful.
1383: If the exit status is zero, the output is considered to be
1384: replacement text, even if it empty.
1385: If the exit status is nonzero, any output is ignored and the
1386: original file is used.
1387: For compatibility with previous versions of
1388: .Nm less ,
1389: if
1390: .Ev LESSOPEN
1391: starts with only one vertical bar, the exit status
1392: of the preprocessor is ignored.
1393: .Pp
1.1 millert 1394: When an input pipe is used, a LESSCLOSE postprocessor can be used,
1395: but it is usually not necessary since there is no replacement file to clean up.
1396: In this case, the replacement file name passed to the LESSCLOSE
1397: postprocessor is "-".
1.23 shadchin 1398: .Pp
1399: For compatibility with previous versions of
1400: .Nm less ,
1401: the input preprocessor or pipe is not used if
1402: .Nm
1403: is viewing standard input.
1404: However, if the first character of LESSOPEN is a dash (-),
1405: the input preprocessor is used on standard input as well as other files.
1406: In this case, the dash is not considered to be part of
1407: the preprocessor command.
1408: If standard input is being viewed, the input preprocessor is passed
1409: a file name consisting of a single dash.
1410: Similarly, if the first two characters of LESSOPEN are vertical bar and dash
1.32 shadchin 1411: (|-) or two vertical bars and a dash (||-),
1412: the input pipe is used on standard input as well as other files.
1.23 shadchin 1413: Again, in this case the dash is not considered to be part of
1414: the input pipe command.
1.1 millert 1415: .Sh NATIONAL CHARACTER SETS
1416: There are three types of characters in the input file:
1417: .Bl -tag -width "control characters"
1418: .It normal characters
1419: Can be displayed directly to the screen.
1420: .It control characters
1421: Should not be displayed directly, but are expected to be found
1422: in ordinary text files (such as backspace and tab).
1423: .It binary characters
1424: Should not be displayed directly and are not expected to be found
1425: in text files.
1426: .El
1427: .Pp
1428: A "character set" is simply a description of which characters are to
1429: be considered normal, control, and binary.
1430: .Nm
1.51 tb 1431: will determine the character set to use from the environment (see
1432: .Xr locale 1 ) .
1.1 millert 1433: .Pp
1434: Control and binary characters are displayed in standout (reverse video).
1435: Each such character is displayed in caret notation if possible
1436: (e.g. ^A for control-A).
1437: Caret notation is used only if inverting the 0100 bit results in a
1438: normal printable character.
1439: Otherwise, the character is displayed as a hex number in angle brackets.
1440: This format can be changed by setting the
1441: .Ev LESSBINFMT
1442: environment variable.
1443: LESSBINFMT may begin with a "*" and one character to select
1444: the display attribute:
1445: "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout,
1446: and "*n" is normal.
1447: If LESSBINFMT does not begin with a "*", normal attribute is assumed.
1448: The remainder of LESSBINFMT is a string which may include one
1449: printf-style escape sequence (a % followed by x, X, o, d, etc.).
1450: For example, if LESSBINFMT is "*u[%x]", binary characters
1451: are displayed in underlined hexadecimal surrounded by brackets.
1.23 shadchin 1452: The default if no LESSBINFMT is specified is "*s<%02X>".
1453: Warning: the result of expanding the character via LESSBINFMT must
1454: be less than 31 characters.
1455: .Pp
1456: When the character set is utf-8, the
1457: .Ev LESSUTFBINFMT
1458: environment variable
1459: acts similarly to LESSBINFMT but it applies to Unicode code points
1460: that were successfully decoded but are unsuitable for display (e.g.,
1461: unassigned code points).
1462: Its default value is "<U+%04lX>".
1463: Note that LESSUTFBINFMT and LESSBINFMT share their display attribute
1464: setting ("*x") so specifying one will affect both;
1465: LESSUTFBINFMT is read after LESSBINFMT so its setting, if any,
1466: will have priority.
1467: Problematic octets in a UTF-8 file (octets of a truncated sequence,
1468: octets of a complete but non-shortest form sequence, illegal octets,
1469: and stray trailing octets)
1470: are displayed individually using LESSBINFMT so as to facilitate diagnostic
1471: of how the UTF-8 file is ill-formed.
1.1 millert 1472: .Sh PROMPTS
1.44 bentley 1473: The
1474: .Fl P
1475: option allows you to tailor the prompt to your preference.
1476: The string given to the
1477: .Fl P
1478: option replaces the specified prompt string.
1.1 millert 1479: Certain characters in the string are interpreted specially.
1480: The prompt mechanism is rather complicated to provide flexibility,
1481: but the ordinary user need not understand the details of constructing
1482: personalized prompt strings.
1483: .Pp
1484: A percent sign followed by a single character is expanded
1485: according to what the following character is:
1486: .Bl -tag -width Ds
1487: .It %b Ns Ar X
1488: Replaced by the byte offset into the current input file.
1489: The b is followed by a single character (shown as
1490: .Ar X
1491: above) which specifies the line whose byte offset is to be used.
1492: If the character is a "t", the byte offset of the top line in the
1493: display is used,
1494: an "m" means use the middle line,
1495: a "b" means use the bottom line,
1496: a "B" means use the line just after the bottom line,
1.44 bentley 1497: and a "j" means use the "target" line, as specified by the
1498: .Fl j
1499: option.
1.4 jmc 1500: .It \&%B
1.1 millert 1501: Replaced by the size of the current input file.
1502: .It %c
1503: Replaced by the column number of the text appearing in the first
1504: column of the screen.
1505: .It %d Ns Ar X
1506: Replaced by the page number of a line in the input file.
1507: The line to be used is determined by the
1508: .Ar X ,
1509: as with the %b option.
1.4 jmc 1510: .It \&%D
1.1 millert 1511: Replaced by the number of pages in the input file,
1512: or equivalently, the page number of the last line in the input file.
1513: .It %E
1514: Replaced by the name of the editor (from the
1515: .Ev VISUAL
1516: environment variable, or the
1517: .Ev EDITOR
1518: environment variable if
1519: .Ev VISUAL
1520: is not defined).
1521: See the discussion of the LESSEDIT feature below.
1522: .It %f
1523: Replaced by the name of the current input file.
1.23 shadchin 1524: .It %F
1525: Replaced by the last component of the name of the current input file.
1.1 millert 1526: .It %i
1527: Replaced by the index of the current file in the list of
1528: input files.
1529: .It %l Ns Ar X
1530: Replaced by the line number of a line in the input file.
1531: The line to be used is determined by the
1532: .Ar X ,
1533: as with the %b option.
1534: .It %L
1535: Replaced by the line number of the last line in the input file.
1536: .It %m
1537: Replaced by the total number of input files.
1538: .It %p Ns Ar X
1539: Replaced by the percent into the current input file, based on byte offsets.
1540: The line used is determined by the
1541: .Ar X ,
1542: as with the %b option.
1.4 jmc 1543: .It \&%P Ns Ar X
1.1 millert 1544: Replaced by the percent into the current input file, based on line numbers.
1545: The line used is determined by the
1546: .Ar X ,
1547: as with the %b option.
1548: .It %s
1549: Same as %B.
1550: .It %t
1551: Causes any trailing spaces to be removed.
1552: Usually used at the end of the string, but may appear anywhere.
1553: .It %x
1554: Replaced by the name of the next input file in the list.
1555: .El
1556: .Pp
1557: If any item is unknown (for example, the file size if input is a pipe),
1558: a question mark is printed instead.
1559: .Pp
1560: The format of the prompt string can be changed depending on certain conditions.
1561: A question mark followed by a single character acts like an "IF":
1562: depending on the following character, a condition is evaluated.
1563: If the condition is true, any characters following the question mark
1564: and condition character, up to a period, are included in the prompt.
1565: If the condition is false, such characters are not included.
1566: A colon appearing between the question mark and the
1567: period can be used to establish an "ELSE": any characters between
1568: the colon and the period are included in the string, if and only if
1569: the IF condition is false.
1570: Condition characters (which follow a question mark) may be:
1571: .Bl -tag -width Ds
1572: .It ?a
1573: True if any characters have been included in the prompt so far.
1574: .It ?b Ns Ar X
1575: True if the byte offset of the specified line is known.
1576: .It ?B
1577: True if the size of the current input file is known.
1578: .It ?c
1579: True if the text is horizontally shifted (%c is not zero).
1580: .It ?d Ns Ar X
1581: True if the page number of the specified line is known.
1582: .It ?e
1583: True if at end-of-file.
1584: .It ?f
1585: True if there is an input filename
1586: (that is, if input is not a pipe).
1587: .It ?l Ns Ar X
1588: True if the line number of the specified line is known.
1589: .It ?L
1590: True if the line number of the last line in the file is known.
1591: .It ?m
1592: True if there is more than one input file.
1593: .It ?n
1594: True if this is the first prompt in a new input file.
1595: .It ?p Ns Ar X
1596: True if the percent into the current input file, based on byte offsets,
1597: of the specified line is known.
1598: .It ?P Ns Ar X
1599: True if the percent into the current input file, based on line numbers,
1600: of the specified line is known.
1601: .It ?s
1602: Same as "?B".
1603: .It ?x
1604: True if there is a next input file
1605: (that is, if the current input file is not the last one).
1606: .El
1607: .Pp
1608: Any characters other than the special ones
1609: (question mark, colon, period, percent, and backslash)
1610: become literally part of the prompt.
1611: Any of the special characters may be included in the prompt literally
1612: by preceding it with a backslash.
1613: .Pp
1614: Some examples:
1615: .Pp
1616: .Dl ?f%f:Standard input.
1617: .Pp
1618: This prompt prints the filename, if known;
1619: otherwise the string "Standard input".
1620: .Pp
1621: .Dl ?f%f .?ltLine %lt:?pt%pt\e%:?btByte %bt:-...
1622: .Pp
1623: This prompt would print the filename, if known.
1624: The filename is followed by the line number, if known,
1625: otherwise the percent if known, otherwise the byte offset if known.
1626: Otherwise, a dash is printed.
1627: Notice how each question mark has a matching period,
1628: and how the % after the %pt
1629: is included literally by escaping it with a backslash.
1630: .Pp
1631: .Dl ?n?f%f\ .?m(file\ %i\ of\ %m)\ ..?e(END)\ ?x-\ Next\e:\ %x..%t
1632: .Pp
1633: This prints the filename if this is the first prompt in a file,
1634: followed by the "file N of N" message if there is more
1635: than one input file.
1636: Then, if we are at end-of-file, the string "(END)" is printed
1637: followed by the name of the next file, if there is one.
1638: Finally, any trailing spaces are truncated.
1639: This is the default prompt.
1640: For reference, here are the defaults for
1.44 bentley 1641: the other two prompts
1642: .Po
1643: .Fl m
1644: and
1645: .Fl M
1646: respectively
1647: .Pc .
1.1 millert 1648: Each is broken into two lines here for readability only.
1649: .Bd -literal -offset indent
1.19 ray 1650: ?f%f\ .?m(file\ %i\ of\ %m)\ .?e(END)\ ?x-\ Next\e:\ %x.:
1.1 millert 1651: ?pB%pB\e%:byte\ %bB?s/%s...%t
1652:
1653: ?f%f\ .?n?m(file\ %i\ of\ %m)\ ..?ltlines\ %lt-%lb?L/%L.\ :
1654: byte\ %bB?s/%s.\ .?e(END)\ ?x-\ Next\e:\ %x.:?pB%pB\e%..%t
1655: .Ed
1656: .Pp
1657: And here is the default message produced by the = command:
1658: .Bd -literal -offset indent
1659: ?f%f\ .?m(file\ %i\ of\ %m)\ .?ltlines\ %lt-%lb?L/%L.\ .
1660: byte\ %bB?s/%s.\ ?e(END)\ :?pB%pB\e%..%t
1661: .Ed
1662: .Pp
1663: The prompt expansion features are also used for another purpose:
1664: if an environment variable
1665: .Ev LESSEDIT
1666: is defined, it is used as the command to be executed when the v command
1667: is invoked.
1668: The LESSEDIT string is expanded in the same way as the prompt strings.
1669: The default value for LESSEDIT is:
1670: .Pp
1671: .Dl %E\ ?lm+%lm.\ %f
1672: .Pp
1673: Note that this expands to the editor name, followed by a + and the
1674: line number, followed by the file name.
1675: If your editor does not accept the "+linenumber" syntax, or has other
1676: differences in invocation syntax, the
1677: .Ev LESSEDIT
1678: variable can be changed to modify this default.
1679: .Sh SECURITY
1680: When the environment variable
1681: .Ev LESSSECURE
1682: is set to 1,
1683: .Nm
1684: runs in a "secure" mode.
1685: This means these features are disabled:
1686: .Bl -tag -width Ds
1687: .It |
1688: The pipe command.
1689: .It :e
1690: The examine command.
1691: .It v
1692: The editing command.
1693: .It s -o
1694: Log files.
1.44 bentley 1695: .It Fl k
1.1 millert 1696: Use of lesskey files.
1.44 bentley 1697: .It Fl t
1.1 millert 1698: Use of tags files.
1699: .It " "
1700: Metacharacters in filenames, such as "*".
1701: .It " "
1702: Filename completion (TAB, ^L).
1703: .El
1.23 shadchin 1704: .Sh COMPATIBILITY WITH MORE
1705: If the environment variable
1706: .Ev LESS_IS_MORE
1707: is set to 1,
1708: or if the program is invoked via a file link named "more",
1709: .Nm
1710: behaves (mostly) in conformance with the POSIX "more" command specification.
1711: In this mode, less behaves differently in these ways:
1712: .Pp
1.43 jmc 1713: The sense of the
1714: .Fl c
1715: option is inverted:
1716: when
1717: .Xr more 1
1718: changes the display,
1719: the default is to scroll from the bottom of the screen,
1720: and the
1721: .Fl c
1722: option causes it to paint from the top line down.
1723: .Pp
1.37 jmc 1724: The
1725: .Fl e
1726: option works differently:
1727: it causes
1728: .Xr more 1
1729: to exit the first time it reaches EOF,
1730: not the second.
1.42 millert 1731: .Pp
1732: The
1733: .Fl i
1734: option acts like the
1735: .Fl I
1736: option.
1737: The normal behavior of the
1738: .Fl i
1739: option is unavailable in this mode.
1.23 shadchin 1740: .Pp
1.37 jmc 1741: The
1742: .Fl m
1743: option works differently:
1744: if it is not specified, the medium prompt is used;
1745: if it is specified, the short prompt is used.
1.23 shadchin 1746: .Pp
1.37 jmc 1747: The
1748: .Fl n
1749: option acts like the
1750: .Fl z
1751: option.
1752: The normal behavior of the
1753: .Fl n
1754: option is unavailable in this mode.
1755: .Pp
1756: The parameter to the
1757: .Fl p
1758: option is taken to be a
1.23 shadchin 1759: command rather than a search pattern.
1760: .Pp
1.43 jmc 1761: Options to suppress error messages when the terminal is dumb
1762: .Pq Fl d ,
1763: suppress highlighting of strings in search results
1764: .Pq Fl G ,
1765: and disable termcap initialization
1766: .Pq Fl X
1767: are on by default.
1768: .Pp
1.23 shadchin 1769: The
1770: .Ev LESS
1.39 jmc 1771: environment variables are ignored, and the
1.23 shadchin 1772: .Ev MORE
1773: environment variable is used in its place.
1.3 jmc 1774: .Sh ENVIRONMENT
1.1 millert 1775: Environment variables may be specified either in the system environment
1776: as usual, or in a
1777: .Xr lesskey 1
1778: file.
1779: If environment variables are defined in more than one place,
1780: variables defined in a local lesskey file take precedence over
1781: variables defined in the system environment, which take precedence
1782: over variables defined in the system-wide lesskey file.
1.38 jmc 1783: .Bl -tag -width LESSANSIENDCHARS
1.1 millert 1784: .It Ev COLUMNS
1785: Sets the number of columns on the screen.
1.41 jmc 1786: Takes precedence over the number of columns specified by the
1787: .Ev TERM
1788: variable,
1789: but may be overridden by window systems which support
1790: .Dv TIOCGWINSZ .
1.1 millert 1791: .It Ev EDITOR
1.41 jmc 1792: Specifies the default editor if
1793: .Ev VISUAL
1794: is not set.
1795: If neither are set,
1796: .Xr vi 1
1797: is used.
1.1 millert 1798: .It Ev HOME
1799: Name of the user's home directory
1800: (used to find a lesskey file).
1801: .It Ev LANG
1802: Language for determining the character set.
1803: .It Ev LC_CTYPE
1.52 schwarze 1804: The character encoding
1805: .Xr locale 1 .
1806: It decides which byte sequences form characters, what their display
1807: width is, and which characters are composing or combining characters.
1.1 millert 1808: .It Ev LESS
1809: Options which are passed to
1810: .Nm
1811: automatically.
1.38 jmc 1812: Command line options override the
1813: .Ev LESS
1814: environment variable.
1815: .Pp
1.44 bentley 1816: Some options like
1817: .Fl k
1818: require a string to follow the option letter.
1.38 jmc 1819: The string for that option is considered to end when a dollar sign ($) is found.
1820: For example, to separate a prompt value from any other options
1821: with dollar sign between them:
1822: .Pp
1823: .Dl LESS="-Ps--More--$-C -e"
1824: .Pp
1.44 bentley 1825: If the
1826: .Fl -use-backslash
1827: option appears earlier in the options, then
1.38 jmc 1828: a dollar sign or backslash may be included literally in an option string
1829: by preceding it with a backslash.
1.44 bentley 1830: If the
1831: .Fl -use-backslash
1832: option is not in effect, then backslashes are
1.38 jmc 1833: not treated specially, and there is no way to include a dollar sign
1834: in the option string.
1.1 millert 1835: .It Ev LESSANSIENDCHARS
1.23 shadchin 1836: Characters which may end an ANSI color escape sequence
1.1 millert 1837: (default "m").
1.23 shadchin 1838: .It Ev LESSANSIMIDCHARS
1839: Characters which may appear between the ESC character and the
1840: end character in an ANSI color escape sequence
1841: (default "0123456789;[?!"'#%()*+\ ").
1.1 millert 1842: .It Ev LESSBINFMT
1843: Format for displaying non-printable, non-control characters.
1844: .It Ev LESSCLOSE
1845: Command line to invoke the (optional) input-postprocessor.
1846: .It Ev LESSEDIT
1847: Editor prototype string (used for the v command).
1848: See discussion under
1849: .Sx PROMPTS .
1.23 shadchin 1850: .It Ev LESSHISTFILE
1851: Name of the history file used to remember search commands and
1852: shell commands between invocations of
1853: .Nm less .
1854: If set to "-" or "/dev/null", a history file is not used.
1.25 nicm 1855: The default is "-".
1.23 shadchin 1856: .It Ev LESSHISTSIZE
1857: The maximum number of commands to save in the history file.
1858: The default is 100.
1.1 millert 1859: .It Ev LESSKEY
1.54 naddy 1860: Name of the default
1861: .Xr lesskey 1
1862: file.
1.1 millert 1863: .It Ev LESSKEY_SYSTEM
1.54 naddy 1864: Name of the default system-wide
1865: .Xr lesskey 1
1866: file.
1.1 millert 1867: .It Ev LESSMETACHARS
1868: List of characters which are considered "metacharacters" by the shell.
1869: .It Ev LESSMETAESCAPE
1870: Prefix which
1871: .Nm
1872: will add before each metacharacter in a command sent to the shell.
1873: If LESSMETAESCAPE is an empty string, commands containing
1874: metacharacters will not be passed to the shell.
1875: .It Ev LESSOPEN
1876: Command line to invoke the (optional) input-preprocessor.
1877: .It Ev LESSSECURE
1878: Runs less in "secure" mode.
1879: See discussion under
1880: .Sx SECURITY .
1881: .It Ev LESSSEPARATOR
1882: String to be appended to a directory name in filename completion.
1.23 shadchin 1883: .It Ev LESSUTFBINFMT
1884: Format for displaying non-printable Unicode code points.
1885: .It Ev LESS_IS_MORE
1886: Emulate the
1887: .Xr more 1
1888: command.
1.1 millert 1889: .It Ev LINES
1890: Sets the number of lines on the screen.
1.41 jmc 1891: Takes precedence over the number of lines specified by the TERM variable,
1892: but may be overridden by window systems which support
1893: .Dv TIOCGWINSZ .
1.32 shadchin 1894: .It Ev MORE
1895: Options which are passed to
1896: .Nm
1.35 jmc 1897: automatically when running in
1.39 jmc 1898: .Xr more 1
1.32 shadchin 1899: compatible mode.
1.1 millert 1900: .It Ev SHELL
1.46 nicm 1901: The shell used to expand filenames.
1.1 millert 1902: .It Ev TERM
1.41 jmc 1903: Specifies the terminal type.
1904: Used by
1.1 millert 1905: .Nm
1.41 jmc 1906: to get the terminal characteristics necessary to manipulate the screen.
1.1 millert 1907: .It Ev VISUAL
1.41 jmc 1908: Specifies the default editor.
1909: If not set,
1.45 jmc 1910: .Ev EDITOR
1911: is used;
1.41 jmc 1912: if that is not set,
1913: .Xr vi 1
1914: is used.
1.1 millert 1915: .El
1916: .Sh SEE ALSO
1.37 jmc 1917: .Xr lesskey 1 ,
1918: .Xr more 1
1.56 ! jmc 1919: .Sh HISTORY
! 1920: .Nm
! 1921: was first published in 1985 and has been available since
! 1922: .Ox 2.0 .
1.7 jmc 1923: .Sh AUTHORS
1.56 ! jmc 1924: .An Mark Nudelman
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