xref: /freebsd/contrib/less/NEWS (revision 87c1627502a5dde91e5284118eec8682b60f27a2)
1
2                     NEWS about less
3
4======================================================================
5
6  For the latest news about less, see the "less" Web page:
7      http://www.greenwoodsoftware.com/less
8  You can also download the latest version of less from there.
9
10  To report bugs, suggestions or comments, send email to bug-less@gnu.org.
11
12======================================================================
13
14	Major changes between "less" versions 451 and 456
15
16* Allow backslash escaping of metacharacters in LESS environment variable.
17
18* Don't quit if syntax errors are found in command line options.
19
20* Increase sizes of some internal buffers.
21
22* Fix configure bug with --with-regex=none.
23
24* Fix crash with "stty rows 0".
25
26* Fix Win32 attribute display bug.
27
28======================================================================
29
30	Major changes between "less" versions 444 and 451
31
32* Add ESC-F command to keep reading data until a pattern is found.
33
34* Use exit code of LESSOPEN script if LESSOPEN starts with "||".
35
36* When up/down arrow is used on the command line immediately after
37  typing text, the next command starting with that text is found.
38
39* Add support for GNU regex.
40
41* Add configure option --with-regex=none and fix compile errors
42  when compiling with no regex library.
43
44* Fix bugs handling SGR sequences in Win32.
45
46* Fix possible crashes caused by malformed LESSOPEN or
47  LESSCLOSE variables.
48
49* Fix bug highlighting text which is discontiguous in the file
50  due to backspace processing.
51
52* Fix bug in displaying status column when scrolling backwards
53  with -J and -S in effect.
54
55======================================================================
56
57	Major changes between "less" versions 443 and 444
58
59* Fix bug in unget handling that can cause strange effects on the
60  command line.
61
62* Remove vestiges of obsolete -l option that can cause a crash.
63
64======================================================================
65
66	Major changes between "less" versions 436 and 443
67
68* Change search behavior such that when a search is given an explicit
69  pattern, the entire displayed screen is included in the search and
70  not just the portion after the target line.
71
72* Add -A option to change search behavior to the old way: only
73  the portion of the screen after the target line is searched.
74
75* Add %F formatting to prompt strings, replaced by the last component
76  of the input file.
77
78* Control-G while editing a command exits the command.
79
80* Less now exits with status 2 if control-C is pressed and -K is in effect.
81
82* Fix "ungetc overflow" when passing long commands via the -p option.
83
84* Fix bug in using line filtering via the & command
85  in combination with -i and -I.
86
87* Fix bug in handling negative arguments to the -j option.
88
89* Fix bug in handling %t in prompt strings.
90
91* Improve handling of long option names.
92
93* Improve percentage calculation for very large files.
94
95======================================================================
96
97	Major changes between "less" versions 429 and 436
98
99* Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
100
101* Allow a fraction as the argument to the -# (--shift) option.
102
103* Fix highlight bug when underlined/overstruck text matches at end of line.
104
105* Fix non-regex searches with ctrl-R.
106
107======================================================================
108
109	Major changes between "less" versions 424 and 429
110
111* LESSOPEN pipe will now be used on standard input, if the LESSOPEN
112  environment variable begins with "|-".
113
114* The -D option with one number now means use the normal background color.
115
116* Don't change permissions on history file if it is not a regular file.
117
118* Fix non-ANSI-compliant code that caused problems with some compilers.
119
120* Fix binary file detection in UTF-8 mode.
121
122* Fix display problems with long lines on "ignaw" terminals.
123
124* Fix problem interrupting the line number calculation for initial prompt.
125
126* Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
127
128* Fix highlight bug when searching for underlined/overstruck text.
129
130======================================================================
131
132	Major changes between "less" versions 418 and 424
133
134* New "&" command allows filtering of lines based on a pattern.
135
136* Status column now displays a search match, even if the matched
137  string is scrolled off screen because -S is in effect.
138
139* Improve behavior of -F option.
140
141* Allow CSI character (0x9B) to work in UTF-8 mode.
142
143* Output carriage return at startup in case terminal doesn't default
144  to column 1.
145
146* Fix bug in '' (quote, quote) command after G command.
147
148======================================================================
149
150	Major changes between "less" versions 416 and 418
151
152* Color escape sequences are now supported in WIN32 build.
153
154* Makefile now uses EXEEXT feature of autoconf.
155
156* Fix search bug when using -R and text contains ANSI color escape sequences.
157
158* Fix crash when using -r with UTF-8 text containing 0x9B bytes.
159
160* Fix display bug when using ' command to move less than one page forward.
161
162* Update GPL to version 3.
163
164======================================================================
165
166	Major changes between "less" versions 409 and 416
167
168* New --follow-name option makes F command follow the name of a file
169  rather than the file descriptor if an open file is renamed.
170
171* Make searching with -i/-I work correctly with non-ASCII text.
172
173* Fix DJGPP build.
174
175======================================================================
176
177	Major changes between "less" versions 406 and 409
178
179* Support CSI escape sequences, like SGR escape sequences.
180
181* Fix bug which caused screen to fail to repaint when window is resized.
182
183* Fix bug in using -i and -I flags with non-ASCII text.
184
185* Fix configure bug on systems which don't support langinfo.h.
186
187* Fix crash when searching text containing certain invalid UTF-8 sequences.
188
189======================================================================
190
191	Major changes between "less" versions 394 and 406
192
193* Allow decimal point in number for % (percent) command.
194
195* Allow decimal point in number for -j option (fraction of screen height).
196
197* Make n command fetch previous pattern from history file on first search.
198
199* Don't rewrite history file if it has not changed.
200
201* Don't move to bottom of screen on first page.
202
203* Don't output extraneous newlines, so copy & pasting lines from the
204  output works better.
205
206* The -c option has been made identical with the -C option.
207
208* Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
209  that no history file should be used.
210
211* Search can now find text which follows a null byte, if the PCRE
212  library is used, or if no-regex searching (ctrl-R) is used.
213
214* Better compatibility with POSIX more specification.
215
216* Make -f work for directories.
217
218* Make "t" cmd traverse tags in the correct order.
219
220* Allow a few binary characters in the input file before warning
221  that the file is binary.
222
223* Don't warn that file is binary if it merely contains ANSI color sequences
224  and -R is in effect.
225
226* Update Unicode character tables.
227
228* Support DESTDIR in Makefile.
229
230* Fix bug when filename contains certain shell metacharacters such as "$".
231
232* Fix bug when resizing the window while waiting for input from a pipe.
233
234* Fix configure bugs.
235
236======================================================================
237
238	Major changes between "less" versions 382 and 394
239
240* Add history file to save search and shell command history between
241  invocations of less.
242
243* Improve behavior of history list for search and shell commands.
244
245* Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
246
247* Improve handling of UTF-8 files and commands, including better
248  line wrapping and handling double-width chars.
249
250* Added LESSUTFBINFMT environment variable to control display of
251  non-printable characters in a UTF-8 file.
252
253* Add --with-secure option to configure, to make it easier to
254  build a secure version of less.
255
256* Show search matches in the status column even if search highlights
257  are disabled via the -G option or the ESC-u command.
258
259* Improve performance when the file contains very long lines.
260
261* Add "windows" charset.
262
263* Add man page for lessecho.
264
265* Add support for erase2 character, treated same as erase.
266
267* Use ASCII lowercase/uppercase logic when operating on the command line.
268
269* Update makefile for Borland C++ 5.5.1.
270
271* Fix bug in calculating number of pages for %D prompt.
272
273* Fix bug in handling tag file error.
274
275* Fix obscure bug if input file is deleted while viewing help.
276
277* Fix bug handling filenames which include square brackets.
278
279* Fix possible buffer overflow in "global" tag search.
280
281* Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
282
283* Fix buffer overflow in reverse search.
284
285======================================================================
286
287	Major changes between "less" versions 381 and 382
288
289* Removed some old copyrighted code.
290  This probably breaks OS/9 support.
291
292======================================================================
293
294	Major changes between "less" versions 378 and 381
295
296* New -L option to disable LESSOPEN processing.
297
298* Further support for large (64 bit) file addressing.
299  Large file support is now set up by the configure script.
300
301* Use autoconf 2.54.
302  Replace configure.in, acconfig.h, defines.h.top with configure.ac.
303
304* Overstriking underscore with underscore is now bold or underlined
305  depending on context.
306
307* Use only 7 spaces for line numbers in -N mode, if possible.
308
309* Fix some bugs in handling overstriking in UTF-8 files.
310
311* Fix some nroff issues in the man page.
312
313======================================================================
314
315	Major changes between "less" versions 376 and 378
316
317* Bug fixes:
318  Default buffer space is now 64K as documented.
319  Search highlighting works properly when used with -R.
320  Windows version works properly when input file contains carriage returns.
321  Clean up some compiler warnings.
322
323======================================================================
324
325	Major changes between "less" versions 358 and 376
326
327* -x option can now specify multiple variable-width tab stops.
328
329* -X option no longer disables keypad initialization.
330  New option --no-keypad disables keypad initialization.
331
332* New commands t and T step through multiple tag matches.
333  Added support for "global(1)" tags
334  (see http://www.gnu.org/software/global/global.html).
335
336* New prompt style set by option -Pw defines the message printed
337  while waiting for data in the F command.
338
339* System-wide lesskey file now defaults to sysless in etc directory
340  instead of .sysless in bin directory.
341  Use "configure --sysconfdir=..." to change it.
342  (For backwards compatibility, .sysless in bin is still recognized.)
343
344* Pressing RightArrow or LeftArrow while entering a number now shifts
345  the display N columns rather than editing the number itself.
346
347* Status column (enabled with -J) now shows search results.
348
349* Windows version sets window title.
350
351* Default LESSCHARSET for MS-DOS versions is now "dos".
352
353* Searching works better with ANSI (SGR) escape sequences.
354  ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
355
356* Improved performance in reading very large pipes.
357
358* Eliminated some dependencies on file offets being 32 bits.
359
360* Fixed problems when viewing files with very long lines.
361
362* Fixed overstriking in UTF-8 mode, and overstriking tabs.
363
364* Improved horizontal shifting of text using -R option with ANSI color.
365
366* Improved handling of filenames containing shell metacharacters.
367
368* Some fixes for EBCDIC systems.
369
370* Some fixes for OS/2 systems.
371
372======================================================================
373
374	Major changes between "less" versions 354 and 358
375
376* Add -J (--status-column) option to display a status column.
377
378* Add -# (--shift) option to set default horizontal shift distance.
379  Default horizontal shift distance is now one-half screen width.
380
381* Horizontal shifting does not shift line numbers if -N is in effect.
382
383* Horizontal shifting acts as though -S were set, to avoid confusion.
384
385======================================================================
386
387
388	Major changes between "less" versions 352 and 354
389
390* Allow space after numeric-valued command line options.
391
392* Fix problem with configuring terminal libraries on some systems.
393
394* Add support for PCRE regular expression library.
395
396* Add --with-regex option to configure to allow manually selecting
397  a regular expression library.
398
399* Fix bug compiling with SECURE = 1.
400
401======================================================================
402
403
404	Major changes between "less" versions 346 and 352
405
406* Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
407
408* Add --with-editor option to configure script.
409
410* The -M prompt and = message now show the top and bottom line number.
411
412* Fix bug in running the editor on a file whose name contains quotes, etc.
413
414* Fix bug in horizontal scrolling of long lines.
415
416* Fix bug in doing :d on a file which contains marks.
417
418* Fix bug causing cleared lines to sometimes be filled with standout,
419  bold, underline, etc. on certain terminals.
420
421* Fixes for MS-DOS (DJGPP) version.
422
423======================================================================
424
425
426	Major changes between "less" versions 340 and 346
427
428* The UTF-8 character set is now supported.
429
430* The default character set is now latin1 rather than ascii.
431
432* New option -R (--RAW-CONTROL-CHARS) is like -r but handles
433  long (wrapped) lines correctly, as long as the input contains only
434  normal text and ANSI color escape sequences.
435
436* New option -F (--quit-if-one-screen) quits if the text fits on
437  the first screen.
438
439* The -w option now highlights the target line of a g or p command.
440
441* A system-wide lesskey file is supported (LESSKEY_SYSTEM).
442
443* New escape for prompt strings: %c is replaced by column number.
444
445* New escape for prompt strings: %P is replaced by percentage into
446  file, based on line number rather than byte offset.
447
448* HOME and END keys now jump to beginning of file or end of file.
449
450======================================================================
451
452
453	Major changes between "less" versions 337 and 340
454
455* Command line options for less may now be given in either the old
456  single-letter form, or a new long name form (--option-name).
457  See the less man page or "less --help" for the list of long option names.
458
459* Command line options for lesskey may now be given in a new long name
460  form.  See the lesskey man page for the list of long option names.
461
462* New command -- toggles an option using the long option name.
463
464* New command __ queries an option using the long option name.
465
466* The old -- command is renamed as -!.
467
468* If a ^P is entered between the dash and the option letter of the -
469  command, the message describing the new setting is suppressed.
470
471* Lesskey files may now contain \k escape sequences to represent the
472  "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
473
474* New command :d removes the current file from the list of files.
475
476* New option -~ (like -w before version 335)
477  suppresses tildes after end-of-file.
478
479* Less is now released under the GNU General Public License.
480
481======================================================================
482
483
484	Major changes between "less" versions 335 and 337
485
486* Fixed bugs in "make install".
487
488======================================================================
489
490
491	Major changes between "less" versions 332 and 335
492
493* The old -w flag (suppress tildes after end-of-file) has been removed.
494
495* New -w flag highlights the first new line after a forward-screen.
496
497* New -W flag highlights the first new line after any forward movement.
498
499* Window resize works even if LINES and/or COLUMNS environment
500  variables are incorrect.
501
502* New percent escapes for prompt strings:
503  %d is replaced by the page number, and
504  %D is replaced by the number of pages in the file.
505
506* Added charsets "iso8859" and "ebcdic".
507
508* In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
509
510* Fixed some bugs causing incorrect display on DOS/Windows.
511
512======================================================================
513
514
515	Major changes between "less" versions 330 and 332
516
517* Filenames from the command line are entered into the command history,
518  so UPARROW/DOWNARROW can be used to retrieve them from the :e command.
519
520* Now works correctly on Windows when using a scrolling terminal
521  window (buffer larger than display window).
522
523* On Windows, now restores the console screen on exit.
524  Use -X to get the old behavior.
525
526* Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
527
528* Fixed bug on Windows when piping output of an interactive program.
529
530* Fixed bug in tags file processing when tags file has DOS-style
531  line terminators (CR/LF).
532
533* Fixed compilation problem on OS/2.
534
535======================================================================
536
537
538	Major changes between "less" versions 321 and 330
539
540* Now supports filenames containing spaces (in double quotes).
541  New option -" can be used to change the quoting characters.
542
543* In filename completion, a slash is appended to a directory name.
544  If the environment variable LESSSEPARATOR is set, the value of
545  that variable, rather than a slash, is appended.
546
547* LeftArrow and RightArrow are same as ESC-[ and ESC-].
548
549* Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
550
551* A "quit" command defined in a lesskey file may now have an "extra"
552  string, which is used to return an exit code from less when it quits.
553
554* New environment variables LESSMETACHARS and LESSMETAESCAPE provide
555  more control over how less interfaces to the shell.
556
557* Ported to Microsoft Visual C compiler for Windows.
558
559* Ported to DJGPP compiler for MS-DOS.
560
561* Bug fixes.
562
563======================================================================
564
565
566	Major changes between "less" versions 291 and 321
567
568* Command line at bottom of screen now scrolls, so it can be longer
569  than the screen width.
570
571* New commands ESC-] and ESC-[ scroll the display horizontally.
572
573* New command ESC-SPACE scrolls forward a full screen, even if it
574  hits end-of-file.
575
576* Alternate modifiers for search commands: ^N is same as !,
577  ^F is same as @, and ^E is same as *.
578
579* New modifier for search commands: ^K means highlight the matches
580  currently on-screen, but don't move to the first match.
581
582* New modifier for search commands: ^R means don't use regular
583  expressions in the search.
584
585* Environment variable LESSKEY gives name of default lesskey file.
586
587* Environment variable LESSSECURE will force less to run in
588  "secure" mode.
589
590* Command line argument "--" signals that the rest of the arguments
591  are files (not option flags).
592
593* Help file (less.hlp) is no longer installed.  Help text is now
594  embedded in the less executable itself.
595
596* Added -Ph to change the prompt for the help text.
597  Added -Ps to change the default short prompt (same as plain -P).
598
599* Ported to the Borland C compiler for MS-DOS.
600
601* Ported to Windows 95 & Windows NT.
602
603* Ported to OS-9.
604
605* Ported to GNU Hurd.
606
607======================================================================
608
609
610	Major changes between "less" versions 290 and 291
611
612* Less environment variables can be specified in lesskey files.
613
614* Fixed MS-DOS build.
615
616======================================================================
617
618
619	Major changes between "less" versions 278 and 290
620
621* Accepts GNU-style options "--help" and "--version".
622
623* OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
624
625* Bug fixes
626
627======================================================================
628
629
630	Major changes between "less" versions 252 and 278
631
632* A LESSOPEN preprocessor may now pipe the converted file data to less,
633  rather than writing it to a temporary file.
634
635* Search pattern highlighting has been fixed.  It now highlights
636  reliably, even if a string is split across two screen lines,
637  contains TABs, etc.
638
639* The -F flag (which suppress search highlighting) has been changed
640  to -G.  A new flag, -g, changes search highlighting to highlight
641  only the string found by the last search command, instead of all
642  strings which match the last search command.
643
644* New flag -I acts like -i, but ignores case even if the search
645  pattern contains uppercase letters.
646
647* Less now checks for the environment variable VISUAL before EDITOR.
648
649* Ported to OS/2.
650
651======================================================================
652
653
654	Major changes between "less" versions 237 and 252
655
656* Changes in line-editing keys:
657  The literal key is now ^V or ^A rather than \ (backslash).
658  Filename completion commands (TAB and ^L) are disabled
659  when typing a search pattern.
660
661* Line-editing command keys can be redefined using lesskey.
662
663* Lesskey with no input file defaults to $HOME/.lesskey
664  rather than standard input.
665
666* New option -V displays version number of less.
667
668* New option -V displays version number of lesskey.
669
670* Help file less.hlp is now installed by default in /usr/local/share
671  rather than /usr/local/lib.
672
673
674======================================================================
675
676
677	Major changes between "less" versions 170 and 237
678
679* By popular demand, text which matches the current search pattern
680  is highlighted.  New -F flag disables this feature.
681
682* Henry Spencer's regexp.c is now included, for systems which do not
683  have a regular expression library.
684  regexp.c is Copyright (c) 1986 by University of Toronto.
685
686* New line-editing keys, including command history (arrow keys) and
687  filename completion (TAB).
688
689* Input preprocessor allows modification of input files (e.g. uncompress)
690  via LESSOPEN/LESSCLOSE environment variables.
691
692* New -X flag disables sending termcap "ti" and "te" (initialize and
693  deinitialize) strings to the terminal.
694
695* Changing -i from within less now correctly affects a subsequent
696  repeated search.
697
698* Searching for underlined or overstruck text now works when the -u
699  flag is in effect, rather than the -i flag.
700
701* Use setlocale (LANG and LC_CTYPE environment variables) to determine
702  the character set if LESSCHARSET/LESSCHARDEF are not set.
703
704* The default format for displaying binary characters is now standout
705  (reverse video) rather than blinking.  This can still be changed by
706  setting the LESSBINFMT environment variable.
707
708* Use autoconf installation technology.
709
710* Ported to MS-DOS.
711
712        ********************************
713          Things that may surprise you
714        ********************************
715
716* When you enter text at the bottom of the screen (search string,
717  filename, etc.), some keys act different than previously.
718  Specifically, \ (backslash), ESC, TAB, BACKTAB, and control-L
719  now have line editing functions.
720
721* Some previous unofficial versions of less were able to display
722  compressed files.  The new LESSOPEN/LESSCLOSE feature now provides
723  this functionality in a different way.
724
725* Some previous unofficial versions of less provided a -Z flag to
726  set the number of lines of text to retain between full screen scrolls.
727  The -z-n flag (that is, -z with a negative number) provides this
728  functionality.
729
730
731======================================================================
732
733
734	Major changes between "less" versions 123 and 170
735
736* New option -j allows target lines to be positioned anywhere on screen.
737
738* New option -S truncates displayed line at the screen width,
739  rather than wrapping onto the next line.
740
741* New option -y limits amount of forward scroll.
742
743* New option -T specifies a "tags" file.
744
745* Non-printable, non-control characters are displayed in octal.
746  Such characters, as well as control characters, are displayed
747  in blinking mode.
748
749* New command -+ sets an option to its default.
750* New command -- sets an option to the opposite of its default.
751
752* Lesskey file may have a string appended to a key's action,
753  which acts as though typed in after the command.
754
755* New commands ESC-^F and ESC-^B match arbitrary types of brackets.
756
757* New command F monitors a growing file (like "tail -f").
758
759* New command | pipes a section of the input file into a shell command.
760
761* New command :x directly jumps to a file in the command line list.
762
763* Search commands have been enhanced and reorganized:
764	n	Repeat search, same direction.
765	N	Repeat search, opposite direction.
766	ESC-/	Search forward thru file boundaries
767	ESC-?	Search backward thru file boundaries
768	ESC-n	Repeat search thru file boundaries, same direction.
769	ESC-N	Repeat search thru file boundaries, opposite direction.
770  Special character * causes search to search thru file boundaries.
771  Special character @ causes search to begin at start/end of file list.
772
773* Examining a new file adds it to the command line list.
774  A list of files, or an expression which matches more than one file,
775  may be examined; all of them are added to the command line list.
776
777* Environment variables LESSCHARSET and LESSCHARDEF can define
778  a non-ASCII character set.
779
780* Partial support for MSDOS, including options -R for repainting screen
781  on quit, -v/-V to select video mode, and -W to change window size.
782
783
784======================================================================
785
786
787	Major changes between "less" versions 97 and 123
788
789* New option (-N) causes line numbers to be displayed in the
790  text of the file (like vi "set nu").
791
792* New option (-?) prints help message immediately.
793
794* New option (-r) displays "raw" control characters, without
795  mapping them to ^X notation.
796
797* New option (-f) forces less to open non-regular files
798  (directories, etc).
799
800* New option (-k) can be used to specify lesskey files by name.
801
802* New option (-y) can be used to set a forward scroll limit
803  (like -h sets a backward scroll limit).
804
805* File marks (set by the m command) are now preserved when a new
806  file is edited.  The ' command can thus be used to switch files.
807
808* New command ESC-/ searches all files (on the command line)
809  for a pattern.
810
811* New command ESC-n repeats previous search, spanning files.
812
813* The N command has been changed to repeat the previous search
814  in the reverse direction.  The old N command is still available
815  via :n.
816
817* New command ESC-N repeats previous search in the reverse
818  direction and spanning files.
819
820* 8 bit characters are now supported.  A new option (-g) can be
821  used to strip off the eighth bit (the previous behavior).
822
823* Options which take a following string (like -t) may now
824  optionally have a space between the option letter and the string.
825
826* Six new commands { } ( ) [ and ] can be used to match
827  brackets of specific types, similar to vi % command.
828
829* New commands z and w move forward/backward one window and
830  simultaneously set the window size.
831
832* Prompt string expansion now has %L for line number of the last
833  line in the file, and %E for the name of the editor.
834  Also, % escapes which refer to a line (b=bottom, t=top, etc.)
835  can use j for the jump target line.
836
837* New environment variable LESSEDIT can be used to tailor the
838  command string passed to the editor by the v command.
839
840* Examining a file which was previously examined will return
841  to the same position in the file.
842
843* A "%" is expanded to the current filename and a "#" to the
844  previous filename, in both shell commands and the E command.
845  (Previously % worked only in shell commands and # worked
846  only in the E command.)
847
848* New command ":ta" is equivalent to "-t".
849
850* New command "s" is equivalent to "-l".
851
852* The - command may be followed by "+X" to revert to the default
853  for option X, or "-X" to get the opposite of the default.
854
855* Lesskey files may now include characters after the action as
856  extra input to be parsed after the action; for example:
857  "toggle-option X" to toggle a specific option X.
858
859
860
861
862
863