Annotation of src/usr.bin/less/less.man, Revision 1.1.1.1
1.1 etheisen 1:
2:
3:
4: LESS(1) USER COMMANDS LESS(1)
5:
6:
7:
8: NAME
9: less - opposite of more
10:
11: SYNOPSIS
12: less -?
13: less -V
14: less [-[+]aBcCdeEfgGiImMnNqQrsSuUVwX]
15: [-b _b_u_f_s] [-h _l_i_n_e_s] [-j _l_i_n_e] [-k _k_e_y_f_i_l_e]
16: [-{oO} _l_o_g_f_i_l_e] [-p _p_a_t_t_e_r_n] [-P _p_r_o_m_p_t] [-t _t_a_g]
17: [-T _t_a_g_s_f_i_l_e] [-x _t_a_b] [-y _l_i_n_e_s] [-[z] _l_i_n_e_s]
18: [+[+]_c_m_d] [_f_i_l_e_n_a_m_e]...
19:
20:
21: DESCRIPTION
22: _L_e_s_s is a program similar to _m_o_r_e (1), but which allows
23: backward movement in the file as well as forward movement.
24: Also, _l_e_s_s does not have to read the entire input file
25: before starting, so with large input files it starts up fas-
26: ter than text editors like _v_i (1). _L_e_s_s uses termcap (or
27: terminfo on some systems), so it can run on a variety of
28: terminals. There is even limited support for hardcopy ter-
29: minals. (On a hardcopy terminal, lines which should be
30: printed at the top of the screen are prefixed with a caret.)
31:
32: Commands are based on both _m_o_r_e and _v_i. Commands may be pre-
33: ceded by a decimal number, called N in the descriptions
34: below. The number is used by some commands, as indicated.
35:
36:
37: COMMANDS
38: In the following descriptions, ^X means control-X. ESC
39: stands for the ESCAPE key; for example ESC-v means the two
40: character sequence "ESCAPE", then "v".
41:
42: h or H
43: Help: display a summary of these commands. If you for-
44: get all the other commands, remember this one.
45:
46: SPACE or ^V or f or ^F
47: Scroll forward N lines, default one window (see option
48: -z below). If N is more than the screen size, only the
49: final screenful is displayed. Warning: some systems
50: use ^V as a special literalization character.
51:
52: z Like SPACE, but if N is specified, it becomes the new
53: window size.
54:
55: RETURN or ^N or e or ^E or j or ^J
56: Scroll forward N lines, default 1. The entire N lines
57: are displayed, even if N is more than the screen size.
58:
59:
60:
61:
62:
63: 1
64:
65:
66:
67:
68:
69:
70: LESS(1) USER COMMANDS LESS(1)
71:
72:
73:
74: d or ^D
75: Scroll forward N lines, default one half of the screen
76: size. If N is specified, it becomes the new default
77: for subsequent d and u commands.
78:
79: b or ^B or ESC-v
80: Scroll backward N lines, default one window (see option
81: -z below). If N is more than the screen size, only the
82: final screenful is displayed.
83:
84: w Like ESC-v, but if N is specified, it becomes the new
85: window size.
86:
87: y or ^Y or ^P or k or ^K
88: Scroll backward N lines, default 1. The entire N lines
89: are displayed, even if N is more than the screen size.
90: Warning: some systems use ^Y as a special job control
91: character.
92:
93: u or ^U
94: Scroll backward N lines, default one half of the screen
95: size. If N is specified, it becomes the new default
96: for subsequent d and u commands.
97:
98: r or ^R or ^L
99: Repaint the screen.
100:
101: R Repaint the screen, discarding any buffered input.
102: Useful if the file is changing while it is being
103: viewed.
104:
105: F Scroll forward, and keep trying to read when the end of
106: file is reached. Normally this command would be used
107: when already at the end of the file. It is a way to
108: monitor the tail of a file which is growing while it is
109: being viewed. (The behavior is similar to the "tail
110: -f" command.)
111:
112: g or < or ESC-<
113: Go to line N in the file, default 1 (beginning of
114: file). (Warning: this may be slow if N is large.)
115:
116: G or > or ESC->
117: Go to line N in the file, default the end of the file.
118: (Warning: this may be slow if N is large, or if N is
119: not specified and standard input, rather than a file,
120: is being read.)
121:
122: p or %
123: Go to a position N percent into the file. N should be
124: between 0 and 100. (This works if standard input is
125: being read, but only if _l_e_s_s has already read to the
126:
127:
128:
129: 2
130:
131:
132:
133:
134:
135:
136: LESS(1) USER COMMANDS LESS(1)
137:
138:
139:
140: end of the file. It is always fast, but not always
141: useful.)
142:
143: { If a left curly bracket appears in the top line
144: displayed on the screen, the { command will go to the
145: matching right curly bracket. The matching right curly
146: bracket is positioned on the bottom line of the screen.
147: If there is more than one left curly bracket on the top
148: line, a number N may be used to specify the N-th
149: bracket on the line.
150:
151: } If a right curly bracket appears in the bottom line
152: displayed on the screen, the } command will go to the
153: matching left curly bracket. The matching left curly
154: bracket is positioned on the top line of the screen.
155: If there is more than one right curly bracket on the
156: top line, a number N may be used to specify the N-th
157: bracket on the line.
158:
159: ( Like {, but applies to parentheses rather than curly
160: brackets.
161:
162: ) Like }, but applies to parentheses rather than curly
163: brackets.
164:
165: [ Like {, but applies to square brackets rather than
166: curly brackets.
167:
168: ] Like }, but applies to square brackets rather than
169: curly brackets.
170:
171: ESC-^F
172: Followed by two characters, acts like {, but uses the
173: two characters as open and close brackets, respec-
174: tively. For example, "ESC ^F < >" could be used to go
175: forward to the > which matches the < in the top
176: displayed line.
177:
178: ESC-^B
179: Followed by two characters, acts like }, but uses the
180: two characters as open and close brackets, respec-
181: tively. For example, "ESC ^B < >" could be used to go
182: backward to the < which matches the > in the bottom
183: displayed line.
184:
185: m Followed by any lowercase letter, marks the current
186: position with that letter.
187:
188: ' (Single quote.) Followed by any lowercase letter,
189: returns to the position which was previously marked
190: with that letter. Followed by another single quote,
191: returns to the position at which the last "large"
192:
193:
194:
195: 3
196:
197:
198:
199:
200:
201:
202: LESS(1) USER COMMANDS LESS(1)
203:
204:
205:
206: movement command was executed. Followed by a ^ or $,
207: jumps to the beginning or end of the file respectively.
208: Marks are preserved when a new file is examined, so the
209: ' command can be used to switch between input files.
210:
211: ^X^X Same as single quote.
212:
213: /pattern
214: Search forward in the file for the N-th line containing
215: the pattern. N defaults to 1. The pattern is a regu-
216: lar expression, as recognized by _e_d. The search starts
217: at the second line displayed (but see the -a and -j
218: options, which change this).
219:
220: Certain characters are special if entered at the begin-
221: ning of the pattern; they modify the type of search
222: rather than become part of the pattern:
223:
224: ! Search for lines which do NOT match the pattern.
225:
226: * Search multiple files. That is, if the search
227: reaches the end of the current file without find-
228: ing a match, the search continues in the next file
229: in the command line list.
230:
231: @ Begin the search at the first line of the first
232: file in the command line list, regardless of what
233: is currently displayed on the screen or the set-
234: tings of the -a or -j options.
235:
236: ?pattern
237: Search backward in the file for the N-th line contain-
238: ing the pattern. The search starts at the line immedi-
239: ately before the top line displayed.
240:
241: Certain characters are special as in the / command:
242:
243: ! Search for lines which do NOT match the pattern.
244:
245: * Search multiple files. That is, if the search
246: reaches the beginning of the current file without
247: finding a match, the search continues in the pre-
248: vious file in the command line list.
249:
250: @ Begin the search at the last line of the last file
251: in the command line list, regardless of what is
252: currently displayed on the screen or the settings
253: of the -a or -j options.
254:
255: ESC-/pattern
256: Same as "/*".
257:
258:
259:
260:
261: 4
262:
263:
264:
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266:
267:
268: LESS(1) USER COMMANDS LESS(1)
269:
270:
271:
272: ESC-?pattern
273: Same as "?*".
274:
275: n Repeat previous search, for N-th line containing the
276: last pattern. If the previous search was modified by
277: !, the search is made for the N-th line NOT containing
278: the pattern. If the previous search was modified by *,
279: the search continues in the next (or previous) file if
280: not satisfied in the current file. There is no effect
281: if the previous search was modified by @.
282:
283: N Repeat previous search, but in the reverse direction.
284:
285: ESC-n
286: Repeat previous search, but crossing file boundaries.
287: The effect is as if the previous search were modified
288: by *.
289:
290: ESC-N
291: Repeat previous search, but in the reverse direction
292: and crossing file boundaries.
293:
294: ESC-u
295: Undo search highlighting. Turn off highlighting of
296: strings matching the current search pattern. If
297: highlighting is already off because of a previous ESC-u
298: command, turn highlighting back on. Any search command
299: will also turn highlighting back on. (Highlighting can
300: also be disabled by toggling the -G flag; in that case
301: search commands do not turn highlighting back on.)
302:
303: :e [filename]
304: Examine a new file. If the filename is missing, the
305: "current" file (see the :n and :p commands below) from
306: the list of files in the command line is re-examined.
307: A percent sign (%) in the filename is replaced by the
308: name of the current file. A pound sign (#) is replaced
309: by the name of the previously examined file. The
310: filename is inserted into the command line list of
311: files so that it can be seen by subsequent :n and :p
312: commands. If the filename consists of several files,
313: they are all inserted into the list of files and the
314: first one is examined.
315:
316: ^X^V or E
317: Same as :e. Warning: some systems use ^V as a special
318: literalization character.
319:
320: :n Examine the next file (from the list of files given in
321: the command line). If a number N is specified, the N-
322: th next file is examined.
323:
324:
325:
326:
327: 5
328:
329:
330:
331:
332:
333:
334: LESS(1) USER COMMANDS LESS(1)
335:
336:
337:
338: :p Examine the previous file in the command line list. If
339: a number N is specified, the N-th previous file is
340: examined.
341:
342: :x Examine the first file in the command line list. If a
343: number N is specified, the N-th file in the list is
344: examined.
345:
346: = or ^G or :f
347: Prints some information about the file being viewed,
348: including its name and the line number and byte offset
349: of the bottom line being displayed. If possible, it
350: also prints the length of the file, the number of lines
351: in the file and the percent of the file above the last
352: displayed line.
353:
354: - Followed by one of the command line option letters (see
355: below), this will change the setting of that option and
356: print a message describing the new setting. If the
357: option letter has a numeric value (such as -b or -h),
358: or a string value (such as -P or -t), a new value may
359: be entered after the option letter. If no new value is
360: entered, a message describing the current setting is
361: printed and nothing is changed.
362:
363: -+ Followed by one of the command line option letters (see
364: below), this will reset the option to its default set-
365: ting and print a message describing the new setting.
366: (The "-+_X" command does the same thing as "-+_X" on the
367: command line.) This does not work for string-valued
368: options.
369:
370: -- Followed by one of the command line option letters (see
371: below), this will reset the option to the "opposite" of
372: its default setting and print a message describing the
373: new setting. (The "--_X" command does the same thing as
374: "-_X" on the command line.) This does not work for
375: numeric or string-valued options.
376:
377: _ (Underscore.) Followed by one of the command line
378: option letters (see below), this will print a message
379: describing the current setting of that option. The
380: setting of the option is not changed.
381:
382: +cmd Causes the specified cmd to be executed each time a new
383: file is examined. For example, +G causes _l_e_s_s to ini-
384: tially display each file starting at the end rather
385: than the beginning.
386:
387: V Prints the version number of _l_e_s_s being run.
388:
389:
390:
391:
392:
393: 6
394:
395:
396:
397:
398:
399:
400: LESS(1) USER COMMANDS LESS(1)
401:
402:
403:
404: q or :q or :Q or ZZ
405: Exits _l_e_s_s.
406:
407: The following three commands may or may not be valid,
408: depending on your particular installation.
409:
410: v Invokes an editor to edit the current file being
411: viewed. The editor is taken from the environment vari-
412: able VISUAL if defined, or EDITOR if VISUAL is not
413: defined, or defaults to "vi" if neither VISUAL nor EDI-
414: TOR is defined. See also the discussion of LESSEDIT
415: under the section on PROMPTS below.
416:
417: ! shell-command
418: Invokes a shell to run the shell-command given. A per-
419: cent sign (%) in the command is replaced by the name of
420: the current file. A pound sign (#) is replaced by the
421: name of the previously examined file. "!!" repeats the
422: last shell command. "!" with no shell command simply
423: invokes a shell. In all cases, the shell is taken from
424: the environment variable SHELL, or defaults to "sh".
425:
426: | <m> shell-command
427: <m> represents any mark letter. Pipes a section of the
428: input file to the given shell command. The section of
429: the file to be piped is between the first line on the
430: current screen and the position marked by the letter.
431: <m> may also be ^ or $ to indicate beginning or end of
432: file respectively. If <m> is . or newline, the current
433: screen is piped.
434:
435: OPTIONS
436: Command line options are described below. Most options may
437: be changed while _l_e_s_s is running, via the "-" command.
438:
439: Options are also taken from the environment variable "LESS".
440: For example, to avoid typing "less -options ..." each time
441: _l_e_s_s is invoked, you might tell _c_s_h:
442:
443: setenv LESS "-options"
444:
445: or if you use _s_h:
446:
447: LESS="-options"; export LESS
448:
449: The environment variable is parsed before the command line,
450: so command line options override the LESS environment vari-
451: able. If an option appears in the LESS variable, it can be
452: reset to its default on the command line by beginning the
453: command line option with "-+".
454:
455: A dollar sign ($) may be used to signal the end of an option
456:
457:
458:
459: 7
460:
461:
462:
463:
464:
465:
466: LESS(1) USER COMMANDS LESS(1)
467:
468:
469:
470: string. This is important only for options like -P which
471: take a following string.
472:
473: -? This option displays a summary of the commands accepted
474: by _l_e_s_s (the same as the h command). If this option is
475: given, all other options are ignored, and _l_e_s_s exits
476: after the help screen is viewed. (Depending on how
477: your shell interprets the question mark, it may be
478: necessary to quote the question mark, thus: "-\?".)
479:
480: -a Causes searches to start after the last line displayed
481: on the screen, thus skipping all lines displayed on the
482: screen. By default, searches start at the second line
483: on the screen (or after the last found line; see the -j
484: option).
485:
486: -b_n Specifies the number of buffers _l_e_s_s will use for each
487: file. Buffers are 1K, and by default 10 buffers are
488: used for each file (except if the file is a pipe; see
489: the -B option). The number _n specifies a different
490: number of buffers to use.
491:
492: -B By default, when data is read from a pipe, buffers are
493: allocated automatically as needed. If a large amount
494: of data is read from the pipe, this can cause a large
495: amount of memory to be allocated. The -B option dis-
496: ables this automatic allocation of buffers for pipes,
497: so that only the number of buffers specified by the -b
498: option are used. Warning: use of -B can result in
499: erroneous display, since only the most recently viewed
500: part of the file is kept in memory; any earlier data is
501: lost.
502:
503: -c Causes full screen repaints to be painted from the top
504: line down. By default, full screen repaints are done
505: by scrolling from the bottom of the screen.
506:
507: -C The -C option is like -c, but the screen is cleared
508: before it is repainted.
509:
510: -d The -d option suppresses the error message normally
511: displayed if the terminal is dumb; that is, lacks some
512: important capability, such as the ability to clear the
513: screen or scroll backward. The -d option does not oth-
514: erwise change the behavior of _l_e_s_s on a dumb terminal).
515:
516: -Dx_c_o_l_o_r
517: [MS-DOS only] Sets the color of the text displayed. x
518: is a single character which selects the type of text
519: whose color is being set: n=normal, s=standout, d=bold,
520: u=underlined, k=blink. _c_o_l_o_r is a pair of numbers
521: separated by a period. The first number selects the
522:
523:
524:
525: 8
526:
527:
528:
529:
530:
531:
532: LESS(1) USER COMMANDS LESS(1)
533:
534:
535:
536: foreground color and the second selects the background
537: color of the text. A single number _N is the same as
538: _N._0.
539:
540: -e Causes _l_e_s_s to automatically exit the second time it
541: reaches end-of-file. By default, the only way to exit
542: _l_e_s_s is via the "q" command.
543:
544: -E Causes _l_e_s_s to automatically exit the first time it
545: reaches end-of-file.
546:
547: -f Forces non-regular files to be opened. (A non-regular
548: file is a directory or a device special file.) Also
549: suppresses the warning message when a binary file is
550: opened. By default, _l_e_s_s will refuse to open non-
551: regular files.
552:
553: -g Normally, _l_e_s_s will highlight ALL strings which match
554: the last search command. The -g flag changes this
555: behavior to highlight only the particular string which
556: was found by the last search command. This can cause
557: _l_e_s_s to run somewhat faster than the default.
558:
559: -G The -G flag suppresses all highlighting of strings
560: found by search commands.
561:
562: -h_n Specifies a maximum number of lines to scroll backward.
563: If it is necessary to scroll backward more than _n
564: lines, the screen is repainted in a forward direction
565: instead. (If the terminal does not have the ability to
566: scroll backward, -h0 is implied.)
567:
568: -i Causes searches to ignore case; that is, uppercase and
569: lowercase are considered identical. This option is
570: ignored if any uppercase letters appear in the search
571: pattern; in other words, if a pattern contains upper-
572: case letters, then that search does not ignore case.
573:
574: -I Like -i, but searches ignore case even if the pattern
575: contains uppercase letters.
576:
577: -j_n Specifies a line on the screen where the "target" line
578: is to be positioned. A target line is the object of a
579: text search, tag search, jump to a line number, jump to
580: a file percentage, or jump to a marked position. The
581: screen line is specified by a number: the top line on
582: the screen is 1, the next is 2, and so on. The number
583: may be negative to specify a line relative to the bot-
584: tom of the screen: the bottom line on the screen is -1,
585: the second to the bottom is -2, and so on. If the -j
586: option is used, searches begin at the line immediately
587: after the target line. For example, if "-j4" is used,
588:
589:
590:
591: 9
592:
593:
594:
595:
596:
597:
598: LESS(1) USER COMMANDS LESS(1)
599:
600:
601:
602: the target line is the fourth line on the screen, so
603: searches begin at the fifth line on the screen.
604:
605: -k_f_i_l_e_n_a_m_e
606: Causes _l_e_s_s to open and interpret the named file as a
607: _l_e_s_s_k_e_y (1) file. Multiple -k options may be speci-
608: fied. If a file called .less exists in the user's home
609: directory, this file is also used as a _l_e_s_s_k_e_y file.
610:
611: -m Causes _l_e_s_s to prompt verbosely (like _m_o_r_e), with the
612: percent into the file. By default, _l_e_s_s prompts with a
613: colon.
614:
615: -M Causes _l_e_s_s to prompt even more verbosely than _m_o_r_e.
616:
617: -n Suppresses line numbers. The default (to use line
618: numbers) may cause _l_e_s_s to run more slowly in some
619: cases, especially with a very large input file.
620: Suppressing line numbers with the -n flag will avoid
621: this problem. Using line numbers means: the line
622: number will be displayed in the verbose prompt and in
623: the = command, and the v command will pass the current
624: line number to the editor (see also the discussion of
625: LESSEDIT in PROMPTS below).
626:
627: -N Causes a line number to be displayed at the beginning
628: of each line in the display.
629:
630: -o_f_i_l_e_n_a_m_e
631: Causes _l_e_s_s to copy its input to the named file as it
632: is being viewed. This applies only when the input file
633: is a pipe, not an ordinary file. If the file already
634: exists, _l_e_s_s will ask for confirmation before overwrit-
635: ing it.
636:
637: -O_f_i_l_e_n_a_m_e
638: The -O option is like -o, but it will overwrite an
639: existing file without asking for confirmation.
640:
641: If no log file has been specified, the -o and -O
642: options can be used from within _l_e_s_s to specify a log
643: file. Without a file name, they will simply report the
644: name of the log file. The "s" command is equivalent to
645: specifying -o from within _l_e_s_s.
646:
647: -p_p_a_t_t_e_r_n
648: The -p option on the command line is equivalent to
649: specifying +/_p_a_t_t_e_r_n; that is, it tells _l_e_s_s to start
650: at the first occurrence of _p_a_t_t_e_r_n in the file.
651:
652: -P_p_r_o_m_p_t
653: Provides a way to tailor the three prompt styles to
654:
655:
656:
657: 10
658:
659:
660:
661:
662:
663:
664: LESS(1) USER COMMANDS LESS(1)
665:
666:
667:
668: your own preference. This option would normally be put
669: in the LESS environment variable, rather than being
670: typed in with each _l_e_s_s command. Such an option must
671: either be the last option in the LESS variable, or be
672: terminated by a dollar sign. -P followed by a string
673: changes the default (short) prompt to that string. -Pm
674: changes the medium (-m) prompt to the string, and -PM
675: changes the long (-M) prompt. Also, -P= changes the
676: message printed by the = command to the given string.
677: All prompt strings consist of a sequence of letters and
678: special escape sequences. See the section on PROMPTS
679: for more details.
680:
681: -q Causes moderately "quiet" operation: the terminal bell
682: is not rung if an attempt is made to scroll past the
683: end of the file or before the beginning of the file.
684: If the terminal has a "visual bell", it is used
685: instead. The bell will be rung on certain other
686: errors, such as typing an invalid character. The
687: default is to ring the terminal bell in all such cases.
688:
689: -Q Causes totally "quiet" operation: the terminal bell is
690: never rung.
691:
692: -r Causes "raw" control characters to be displayed. The
693: default is to display control characters using the
694: caret notation; for example, a control-A (octal 001) is
695: displayed as "^A". Warning: when the -r flag is used,
696: _l_e_s_s cannot keep track of the actual appearance of the
697: screen (since this depends on how the screen responds
698: to each type of control character). Thus, various
699: display problems may result, such as long lines being
700: split in the wrong place.
701:
702: -s Causes consecutive blank lines to be squeezed into a
703: single blank line. This is useful when viewing _n_r_o_f_f
704: output.
705:
706: -S Causes lines longer than the screen width to be chopped
707: rather than folded. That is, the remainder of a long
708: line is simply discarded. The default is to fold long
709: lines; that is, display the remainder on the next line.
710:
711: -t_t_a_g
712: The -t option, followed immediately by a TAG, will edit
713: the file containing that tag. For this to work, there
714: must be a file called "tags" in the current directory,
715: which was previously built by the _c_t_a_g_s (1) command.
716: This option may also be specified from within _l_e_s_s
717: (using the - command) as a way of examining a new file.
718: The command ":t" is equivalent to specifying -t from
719: within _l_e_s_s.
720:
721:
722:
723: 11
724:
725:
726:
727:
728:
729:
730: LESS(1) USER COMMANDS LESS(1)
731:
732:
733:
734: -T_t_a_g_s_f_i_l_e
735: Specifies a tags file to be used instead of "tags".
736:
737: -u Causes backspaces and carriage returns to be treated as
738: printable characters; that is, they are sent to the
739: terminal when they appear in the input.
740:
741: -U Causes backspaces and carriage returns to be treated as
742: control characters; that is, they are handled as speci-
743: fied by the -r option.
744:
745: By default, if neither -u nor -U is given, backspaces
746: which appear adjacent to an underscore character are
747: treated specially: the underlined text is displayed
748: using the terminal's hardware underlining capability.
749: Also, backspaces which appear between two identical
750: characters are treated specially: the overstruck text
751: is printed using the terminal's hardware boldface capa-
752: bility. Other backspaces are deleted, along with the
753: preceding character. Carriage returns immediately fol-
754: lowed by a newline are deleted. Other carriage returns
755: are handled as specified by the -r option. Text which
756: is overstruck or underlined can be searched for if nei-
757: ther -u nor -U is in effect.
758:
759: -V Displays the version number of _l_e_s_s.
760:
761: -w Causes blank lines to be used to represent lines past
762: the end of the file. By default, a tilde character (~)
763: is used.
764:
765: -x_n Sets tab stops every _n positions. The default for _n is
766: 8.
767:
768: -X Disables sending the termcap initialization and deini-
769: tialization strings to the terminal. This is sometimes
770: desirable if the deinitialization string does something
771: unnecessary, like clearing the screen.
772:
773: -y_n Specifies a maximum number of lines to scroll forward.
774: If it is necessary to scroll forward more than _n lines,
775: the screen is repainted instead. The -c or -C option
776: may be used to repaint from the top of the screen if
777: desired. By default, any forward movement causes
778: scrolling.
779:
780: -[z]_n
781: Changes the default scrolling window size to _n lines.
782: The default is one screenful. The z and w commands can
783: also be used to change the window size. The "z" may be
784: omitted for compatibility with _m_o_r_e. If the number _n is
785: negative, it indicates _n lines less than the current
786:
787:
788:
789: 12
790:
791:
792:
793:
794:
795:
796: LESS(1) USER COMMANDS LESS(1)
797:
798:
799:
800: screen size. For example, if the screen is 24 lines,
801: -_z-_4 sets the scrolling window to 20 lines. If the
802: screen is resized to 40 lines, the scrolling window
803: automatically changes to 36 lines.
804:
805: + If a command line option begins with +, the remainder
806: of that option is taken to be an initial command to
807: _l_e_s_s. For example, +G tells _l_e_s_s to start at the end of
808: the file rather than the beginning, and +/xyz tells it
809: to start at the first occurrence of "xyz" in the file.
810: As a special case, +<number> acts like +<number>g; that
811: is, it starts the display at the specified line number
812: (however, see the caveat under the "g" command above).
813: If the option starts with ++, the initial command
814: applies to every file being viewed, not just the first
815: one. The + command described previously may also be
816: used to set (or change) an initial command for every
817: file.
818:
819:
820: LINE EDITING
821: When entering command line at the bottom of the screen (for
822: example, a filename for the :e command, or the pattern for a
823: search command), certain keys can be used to manipulate the
824: command line. Most commands have an alternate form in [
825: brackets ] which can be used if a key does not exist on a
826: particular keyboard. (The bracketed forms do not work in the
827: MS-DOS version.) Any of these special keys may be entered
828: literally by preceding it with the "literal" character,
829: either ^V or ^A. A backslash itself may also be entered
830: literally by entering two backslashes.
831:
832: LEFTARROW [ ESC-h ]
833: Move the cursor one space to the left.
834:
835: RIGHTARROW [ ESC-l ]
836: Move the cursor one space to the right.
837:
838: ^LEFTARROW [ ESC-b or ESC-LEFTARROW ]
839: (That is, CONTROL and LEFTARROW simultaneously.) Move
840: the cursor one word to the left.
841:
842: ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]
843: (That is, CONTROL and RIGHTARROW simultaneously.) Move
844: the cursor one word to the right.
845:
846: HOME [ ESC-0 ]
847: Move the cursor to the beginning of the line.
848:
849: END [ ESC-$ ]
850: Move the cursor to the end of the line.
851:
852:
853:
854:
855: 13
856:
857:
858:
859:
860:
861:
862: LESS(1) USER COMMANDS LESS(1)
863:
864:
865:
866: BACKSPACE
867: Delete the character to the left of the cursor, or can-
868: cel the command if the command line is empty.
869:
870: DELETE or [ ESC-x ]
871: Delete the character under the cursor.
872:
873: ^BACKSPACE [ ESC-BACKSPACE ]
874: (That is, CONTROL and BACKSPACE simultaneously.) Delete
875: the word to the left of the cursor.
876:
877: ^DELETE [ ESC-X or ESC-DELETE ]
878: (That is, CONTROL and DELETE simultaneously.) Delete
879: the word under the cursor.
880:
881: UPARROW [ ESC-k ]
882: Retrieve the previous command line.
883:
884: DOWNARROW [ ESC-j ]
885: Retrieve the next command line.
886:
887: TAB Complete the partial filename to the left of the cur-
888: sor. If it matches more than one filename, the first
889: match is entered into the command line. Repeated TABs
890: will cycle thru the other matching filenames.
891:
892: BACKTAB [ ESC-TAB ]
893: Like, TAB, but cycles in the reverse direction thru the
894: matching filenames.
895:
896: ^L Complete the partial filename to the left of the cur-
897: sor. If it matches more than one filename, all matches
898: are entered into the command line (if they fit).
899:
900: ^U (Unix) or ESC (MS-DOS)
901: Delete the entire command line, or cancel the command
902: if the command line is empty. If you have changed your
903: line-kill character in Unix to something other than ^U,
904: that character is used instead of ^U.
905:
906:
907: KEY BINDINGS
908: You may define your own _l_e_s_s commands by using the program
909: _l_e_s_s_k_e_y (1) to create a file called ".less" in your home
910: directory. This file specifies a set of command keys and an
911: action associated with each key. You may also use _l_e_s_s_k_e_y
912: to change the line-editing keys (see LINE EDITING). See the
913: _l_e_s_s_k_e_y manual page for more details.
914:
915:
916: INPUT PREPROCESSOR
917: You may define an "input preprocessor" for _l_e_s_s. Before _l_e_s_s
918:
919:
920:
921: 14
922:
923:
924:
925:
926:
927:
928: LESS(1) USER COMMANDS LESS(1)
929:
930:
931:
932: opens a file, it first gives your input preprocessor a
933: chance to modify the way the contents of the file are
934: displayed. An input preprocessor is simply an executable
935: program (or shell script), which writes the contents of the
936: file to a different file, called the replacement file. The
937: contents of the replacement file are then displayed in place
938: of the contents of the original file. However, it will
939: appear to the user as if the original file is opened; that
940: is, _l_e_s_s will display the original filename as the name of
941: the current file.
942:
943: An input preprocessor receives one command line argument,
944: the original filename, as entered by the user. It should
945: create the replacement file, and when finished, print the
946: name of the replacement file to its standard output. If the
947: input preprocessor does not output a replacement filename,
948: _l_e_s_s uses the original file, as normal. The input prepro-
949: cessor is not called when viewing standard input. To set up
950: an input preprocessor, set the LESSOPEN environment variable
951: to a command line which will invoke your input preprocessor.
952: This command line should include one occurrence of the
953: string "%s", which will be replaced by the filename when the
954: input preprocessor command is invoked.
955:
956: When _l_e_s_s closes a file opened in such a way, it will call
957: another program, called the input postprocessor, which may
958: perform any desired clean-up action (such as deleting the
959: replacement file created by LESSOPEN). This program
960: receives two command line arguments, the original filename
961: as entered by the user, and the name of the replacement
962: file. To set up an input postprocessor, set the LESSCLOSE
963: environment variable to a command line which will invoke
964: your input postprocessor. It may include two occurrences of
965: the string "%s"; the first is replaced with the original
966: name of the file and the second with the name of the
967: replacement file, which was output by LESSOPEN.
968:
969: For example, on many Unix systems, these two scripts will
970: allow you to keep files in compressed format, but still let
971: _l_e_s_s view them directly:
972:
973: lessopen.sh:
974: #! /bin/sh
975: case "$1" in
976: *.Z) uncompress -c $1 >/tmp/less.$$ 2>/dev/null
977: if [ -s /tmp/less.$$ ]; then
978: echo /tmp/less.$$
979: else
980: rm -f /tmp/less.$$
981: fi
982: ;;
983: esac
984:
985:
986:
987: 15
988:
989:
990:
991:
992:
993:
994: LESS(1) USER COMMANDS LESS(1)
995:
996:
997:
998: lessclose.sh:
999: #! /bin/sh
1000: rm $2
1001:
1002: To use these scripts, put them both where they can be exe-
1003: cuted and set LESSOPEN="lessopen.sh %s", and
1004: LESSCLOSE="lessclose.sh %s %s". More complex LESSOPEN and
1005: LESSCLOSE scripts may be written to accept other types of
1006: compressed files, and so on.
1007:
1008: It is also possible to set up an input preprocessor to pipe
1009: the file data directly to _l_e_s_s, rather than putting the data
1010: into a replacement file. This avoids the need to decompress
1011: the entire file before starting to view it. An input
1012: preprocessor that works this way is called an input pipe.
1013: An input pipe, instead of writing the name of a replacement
1014: file on its standard output, writes the entire contents of
1015: the replacement file on its standard output. If the input
1016: pipe does not write any characters on its standard output,
1017: then there is no replacement file and _l_e_s_s uses the original
1018: file, as normal. To use an input pipe, make the first char-
1019: acter in the LESSOPEN environment variable a vertical bar
1020: (|) to signify that the input preprocessor is an input pipe.
1021:
1022: For example, on many Unix systems, this script will work
1023: like the previous example scripts:
1024:
1025: lesspipe.sh:
1026: !# /bin/sh
1027: case "$1" in
1028: *.Z) uncompress -c $1 2>/dev/null
1029: ;;
1030: esac
1031:
1032: To use this script, put it where it can be executed and set
1033: LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a
1034: LESSCLOSE postprocessor can be used, but it is usually not
1035: necessary since there is no replacement file to clean up.
1036: In this case, the replacement file name passed to the LESS-
1037: CLOSE postprocessor is "-".
1038:
1039:
1040: NATIONAL CHARACTER SETS
1041: There are three types of characters in the input file:
1042:
1043: normal characters
1044: can be displayed directly to the screen.
1045:
1046: control characters
1047: should not be displayed directly, but are expected to
1048: be found in ordinary text files (such as backspace and
1049: tab).
1050:
1051:
1052:
1053: 16
1054:
1055:
1056:
1057:
1058:
1059:
1060: LESS(1) USER COMMANDS LESS(1)
1061:
1062:
1063:
1064: binary characters
1065: should not be displayed directly and are not expected
1066: to be found in text files.
1067:
1068: A "character set" is simply a description of which charac-
1069: ters are to be considered normal, control, and binary. The
1070: LESSCHARSET environment variable may be used to select a
1071: character set. Possible values for LESSCHARSET are:
1072:
1073: ascii
1074: The default character set. BS, TAB, NL, CR, and
1075: formfeed are control characters, all chars with values
1076: between 127 and 255 are binary, and all others are nor-
1077: mal.
1078:
1079: latin1
1080: Selects the ISO 8859/1 character set. latin-1 is the
1081: same as ASCII, except characters between 161 and 255
1082: are treated as normal characters.
1083:
1084: dos Selects a character set appropriate for MS-DOS.
1085:
1086: koi8-r
1087: Selects a Russian character set.
1088:
1089: next Selects a character set appropriate for NeXT computers.
1090:
1091: In special cases, it may be desired to tailor _l_e_s_s to use a
1092: character set other than the ones definable by LESSCHARSET.
1093: In this case, the environment variable LESSCHARDEF can be
1094: used to define a character set. It should be set to a
1095: string where each character in the string represents one
1096: character in the character set. The character "." is used
1097: for a normal character, "c" for control, and "b" for binary.
1098: A decimal number may be used for repetition. For example,
1099: "bccc4b." would mean character 0 is binary, 1, 2 and 3 are
1100: control, 4, 5, 6 and 7 are binary, and 8 is normal. All
1101: characters after the last are taken to be the same as the
1102: last, so characters 9 through 255 would be normal. (This is
1103: an example, and does not necessarily represent any real
1104: character set.)
1105:
1106: This table shows the value of LESSCHARDEF which is
1107: equivalent to each of the possible values for LESSCHARSET:
1108:
1109: ascii 8bcccbcc18b95.b
1110: latin1 8bcccbcc18b95.33b.
1111: dos 8bcccbcc12bc5b95.b.
1112: koi8-r 8bcccbcc18b95.b128.
1113: next 8bcccbcc18b95.bb125.bb
1114:
1115:
1116:
1117:
1118:
1119: 17
1120:
1121:
1122:
1123:
1124:
1125:
1126: LESS(1) USER COMMANDS LESS(1)
1127:
1128:
1129:
1130: If neither LESSCHARSET nor LESSCHARDEF is set, but your sys-
1131: tem supports the _s_e_t_l_o_c_a_l_e interface, _l_e_s_s will use setlo-
1132: cale to determine the character set. setlocale is con-
1133: trolled by setting the LANG or LC_CTYPE environment vari-
1134: ables.
1135:
1136: Control and binary characters are displayed in standout
1137: (reverse video). Each such character is displayed in caret
1138: notation if possible (e.g. ^A for control-A). Caret nota-
1139: tion is used only if inverting the 0100 bit results in a
1140: normal printable character. Otherwise, the character is
1141: displayed as a hex number in angle brackets. This format
1142: can be changed by setting the LESSBINFMT environment vari-
1143: able. LESSBINFMT may begin with a "*" and one character to
1144: select the display attribute: "*k" is blinking, "*d" is
1145: bold, "*u" is underlined, "*s" is standout. If LESSBINFMT
1146: does not begin with a "*", normal attribute is assumed. The
1147: remainder of LESSBINFMT is a string which may include one
1148: printf-style escape sequence (a % followed by x, X, o, d,
1149: etc.). For example, if LESSBINFMT is "*u[%x]", binary char-
1150: acters are displayed in underlined hexadecimal surrounded by
1151: brackets. The default if no LESSBINFMT is specified is
1152: "*d<%X>".
1153:
1154:
1155: PROMPTS
1156: The -P option allows you to tailor the prompt to your
1157: preference. The string given to the -P option replaces the
1158: specified prompt string. Certain characters in the string
1159: are interpreted specially. The prompt mechanism is rather
1160: complicated to provide flexibility, but the ordinary user
1161: need not understand the details of constructing personalized
1162: prompt strings.
1163:
1164: A percent sign followed by a single character is expanded
1165: according to what the following character is:
1166:
1167: %b_X Replaced by the byte offset into the current input
1168: file. The b is followed by a single character (shown
1169: as _X above) which specifies the line whose byte offset
1170: is to be used. If the character is a "t", the byte
1171: offset of the top line in the display is used, an "m"
1172: means use the middle line, a "b" means use the bottom
1173: line, a "B" means use the line just after the bottom
1174: line, and a "j" means use the "target" line, as speci-
1175: fied by the -j option.
1176:
1177: %B Replaced by the size of the current input file.
1178:
1179: %E Replaced by the name of the editor (from the VISUAL
1180: environment variable, or the EDITOR environment vari-
1181: able if VISUAL is not defined). See the discussion of
1182:
1183:
1184:
1185: 18
1186:
1187:
1188:
1189:
1190:
1191:
1192: LESS(1) USER COMMANDS LESS(1)
1193:
1194:
1195:
1196: the LESSEDIT feature below.
1197:
1198: %f Replaced by the name of the current input file.
1199:
1200: %i Replaced by the index of the current file in the list
1201: of input files.
1202:
1203: %l_X Replaced by the line number of a line in the input
1204: file. The line to be used is determined by the _X, as
1205: with the %b option.
1206:
1207: %L Replaced by the line number of the last line in the
1208: input file.
1209:
1210: %m Replaced by the total number of input files.
1211:
1212: %p_X Replaced by the percent into the current input file.
1213: The line used is determined by the _X as with the %b
1214: option.
1215:
1216: %s Same as %B.
1217:
1218: %t Causes any trailing spaces to be removed. Usually used
1219: at the end of the string, but may appear anywhere.
1220:
1221: %x Replaced by the name of the next input file in the
1222: list.
1223:
1224: If any item is unknown (for example, the file size if input
1225: is a pipe), a question mark is printed instead.
1226:
1227: The format of the prompt string can be changed depending on
1228: certain conditions. A question mark followed by a single
1229: character acts like an "IF": depending on the following
1230: character, a condition is evaluated. If the condition is
1231: true, any characters following the question mark and condi-
1232: tion character, up to a period, are included in the prompt.
1233: If the condition is false, such characters are not included.
1234: A colon appearing between the question mark and the period
1235: can be used to establish an "ELSE": any characters between
1236: the colon and the period are included in the string if and
1237: only if the IF condition is false. Condition characters
1238: (which follow a question mark) may be:
1239:
1240: ?a True if any characters have been included in the prompt
1241: so far.
1242:
1243: ?b_X True if the byte offset of the specified line is known.
1244:
1245: ?B True if the size of current input file is known.
1246:
1247: ?e True if at end-of-file.
1248:
1249:
1250:
1251: 19
1252:
1253:
1254:
1255:
1256:
1257:
1258: LESS(1) USER COMMANDS LESS(1)
1259:
1260:
1261:
1262: ?f True if there is an input filename (that is, if input
1263: is not a pipe).
1264:
1265: ?l_X True if the line number of the specified line is known.
1266:
1267: ?L True if the line number of the last line in the file is
1268: known.
1269:
1270: ?m True if there is more than one input file.
1271:
1272: ?n True if this is the first prompt in a new input file.
1273:
1274: ?p_X True if the percent into the current input file of the
1275: specified line is known.
1276:
1277: ?s Same as "?B".
1278:
1279: ?x True if there is a next input file (that is, if the
1280: current input file is not the last one).
1281:
1282: Any characters other than the special ones (question mark,
1283: colon, period, percent, and backslash) become literally part
1284: of the prompt. Any of the special characters may be
1285: included in the prompt literally by preceding it with a
1286: backslash.
1287:
1288: Some examples:
1289:
1290: ?f%f:Standard input.
1291:
1292: This prompt prints the filename, if known; otherwise the
1293: string "Standard input".
1294:
1295: ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-...
1296:
1297: This prompt would print the filename, if known. The
1298: filename is followed by the line number, if known, otherwise
1299: the percent if known, otherwise the byte offset if known.
1300: Otherwise, a dash is printed. Notice how each question mark
1301: has a matching period, and how the % after the %pt is
1302: included literally by escaping it with a backslash.
1303:
1304: ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t
1305:
1306: This prints the filename if this is the first prompt in a
1307: file, followed by the "file N of N" message if there is more
1308: than one input file. Then, if we are at end-of-file, the
1309: string "(END)" is printed followed by the name of the next
1310: file, if there is one. Finally, any trailing spaces are
1311: truncated. This is the default prompt. For reference, here
1312: are the defaults for the other two prompts (-m and -M
1313: respectively). Each is broken into two lines here for
1314:
1315:
1316:
1317: 20
1318:
1319:
1320:
1321:
1322:
1323:
1324: LESS(1) USER COMMANDS LESS(1)
1325:
1326:
1327:
1328: readability only.
1329:
1330: ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.:
1331: ?pB%pB\%:byte %bB?s/%s...%t
1332:
1333: ?f%f .?n?m(file %i of %m) ..?ltline %lt?L/%L. :byte %bB?s/%s. .
1334: ?e(END) ?x- Next\: %x.:?pB%pB\%..%t
1335:
1336: And here is the default message produced by the = command:
1337:
1338: ?f%f .?m(file %i of %m) .?ltline %lt?L/%L. .
1339: byte %bB?s/%s. ?e(END) :?pB%pB\%..%t
1340:
1341: The prompt expansion features are also used for another pur-
1342: pose: if an environment variable LESSEDIT is defined, it is
1343: used as the command to be executed when the v command is
1344: invoked. The LESSEDIT string is expanded in the same way as
1345: the prompt strings. The default value for LESSEDIT is:
1346:
1347: %E ?lm+%lm. %f
1348:
1349: Note that this expands to the editor name, followed by a +
1350: and the line number, followed by the file name. If your
1351: editor does not accept the "+linenumber" syntax, or has
1352: other differences in invocation syntax, the LESSEDIT vari-
1353: able can be changed to modify this default.
1354:
1355:
1356: ENVIRONMENT VARIABLES
1357: COLUMNS
1358: Sets the number of columns on the screen. Takes pre-
1359: cedence over the number of columns specified by the
1360: TERM variable. (But if you have a windowing system
1361: which supports TIOCGWINSZ or WIOCGETD, the window
1362: system's idea of the screen size takes precedence over
1363: the LINES and COLUMNS environment variables.)
1364:
1365: EDITOR
1366: The name of the editor (used for the v command).
1367:
1368: HOME Name of the user's home directory (used to find a .less
1369: file).
1370:
1371: LANG Language for determining the character set.
1372:
1373: LC_CTYPE
1374: Language for determining the character set.
1375:
1376: LESS Flags which are passed to _l_e_s_s automatically.
1377:
1378: LESSBINFMT
1379: Format for displaying non-printable, non-control
1380:
1381:
1382:
1383: 21
1384:
1385:
1386:
1387:
1388:
1389:
1390: LESS(1) USER COMMANDS LESS(1)
1391:
1392:
1393:
1394: characters.
1395:
1396: LESSCHARDEF
1397: Defines a character set.
1398:
1399: LESSCHARSET
1400: Selects a predefined character set.
1401:
1402: LESSCLOSE
1403: Command line to invoke the (optional) input-
1404: postprocessor.
1405:
1406: LESSEDIT
1407: Editor prototype string (used for the v command). See
1408: discussion under PROMPTS.
1409:
1410: LESSHELP
1411: Name of the help file.
1412:
1413: LESSOPEN
1414: Command line to invoke the (optional) input-
1415: preprocessor.
1416:
1417: LINES
1418: Sets the number of lines on the screen. Takes pre-
1419: cedence over the number of lines specified by the TERM
1420: variable.
1421:
1422: SHELL
1423: The shell used to execute the ! command, as well as to
1424: expand filenames.
1425:
1426: TERM The type of terminal on which _l_e_s_s is being run.
1427:
1428: VISUAL
1429: The name of the editor (used for the v command).
1430:
1431:
1432: SEE ALSO
1433: lesskey(1)
1434:
1435:
1436: WARNINGS
1437: The = command and prompts (unless changed by -P) report the
1438: line number of the line at the top of the screen, but the
1439: byte and percent of the line at the bottom of the screen.
1440:
1441: If the :e command is used to name more than one file, and
1442: one of the named files has been viewed previously, the new
1443: files may be entered into the list in an unexpected order.
1444:
1445:
1446:
1447:
1448:
1449: 22
1450:
1451:
1452:
1453:
1454:
1455:
1456: LESS(1) USER COMMANDS LESS(1)
1457:
1458:
1459:
1460: On certain older terminals (the so-called "magic cookie"
1461: terminals), search highlighting will cause an erroneous
1462: display. On such terminals, search highlighting is disabled
1463: by default to avoid possible problems.
1464:
1465: In certain cases, when search highlighting is enabled and a
1466: search pattern begins with a ^, more text than the matching
1467: string may be highlighted.
1468:
1469:
1470:
1471: COPYRIGHT
1472: Copyright (c) 1984,1985,1989,1994,1995 Mark Nudelman
1473:
1474:
1475:
1476:
1477:
1478:
1479:
1480:
1481:
1482:
1483:
1484:
1485:
1486:
1487:
1488:
1489:
1490:
1491:
1492:
1493:
1494:
1495:
1496:
1497:
1498:
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1501:
1502:
1503:
1504:
1505:
1506:
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1508:
1509:
1510:
1511:
1512:
1513:
1514:
1515: 23
1516:
1517:
1518:
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