4 ======================================================================
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.
10 To report bugs, suggestions or comments, send email to bug-less@gnu.org.
12 ======================================================================
14 Major changes between "less" versions 451 and 458
16 * Allow backslash escaping of metacharacters in LESS environment variable
17 after the --use-backslash option.
19 * Don't quit if syntax errors are found in command line options.
21 * Increase sizes of some internal buffers.
23 * Fix configure bug with --with-regex=none.
25 * Fix crash with "stty rows 0".
27 * Fix Win32 attribute display bug.
29 * Fix display bug when using up/down arrow on the command line.
31 ======================================================================
33 Major changes between "less" versions 444 and 451
35 * Add ESC-F command to keep reading data until a pattern is found.
37 * Use exit code of LESSOPEN script if LESSOPEN starts with "||".
39 * When up/down arrow is used on the command line immediately after
40 typing text, the next command starting with that text is found.
42 * Add support for GNU regex.
44 * Add configure option --with-regex=none and fix compile errors
45 when compiling with no regex library.
47 * Fix bugs handling SGR sequences in Win32.
49 * Fix possible crashes caused by malformed LESSOPEN or
52 * Fix bug highlighting text which is discontiguous in the file
53 due to backspace processing.
55 * Fix bug in displaying status column when scrolling backwards
56 with -J and -S in effect.
58 ======================================================================
60 Major changes between "less" versions 443 and 444
62 * Fix bug in unget handling that can cause strange effects on the
65 * Remove vestiges of obsolete -l option that can cause a crash.
67 ======================================================================
69 Major changes between "less" versions 436 and 443
71 * Change search behavior such that when a search is given an explicit
72 pattern, the entire displayed screen is included in the search and
73 not just the portion after the target line.
75 * Add -A option to change search behavior to the old way: only
76 the portion of the screen after the target line is searched.
78 * Add %F formatting to prompt strings, replaced by the last component
81 * Control-G while editing a command exits the command.
83 * Less now exits with status 2 if control-C is pressed and -K is in effect.
85 * Fix "ungetc overflow" when passing long commands via the -p option.
87 * Fix bug in using line filtering via the & command
88 in combination with -i and -I.
90 * Fix bug in handling negative arguments to the -j option.
92 * Fix bug in handling %t in prompt strings.
94 * Improve handling of long option names.
96 * Improve percentage calculation for very large files.
98 ======================================================================
100 Major changes between "less" versions 429 and 436
102 * Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
104 * Allow a fraction as the argument to the -# (--shift) option.
106 * Fix highlight bug when underlined/overstruck text matches at end of line.
108 * Fix non-regex searches with ctrl-R.
110 ======================================================================
112 Major changes between "less" versions 424 and 429
114 * LESSOPEN pipe will now be used on standard input, if the LESSOPEN
115 environment variable begins with "|-".
117 * The -D option with one number now means use the normal background color.
119 * Don't change permissions on history file if it is not a regular file.
121 * Fix non-ANSI-compliant code that caused problems with some compilers.
123 * Fix binary file detection in UTF-8 mode.
125 * Fix display problems with long lines on "ignaw" terminals.
127 * Fix problem interrupting the line number calculation for initial prompt.
129 * Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
131 * Fix highlight bug when searching for underlined/overstruck text.
133 ======================================================================
135 Major changes between "less" versions 418 and 424
137 * New "&" command allows filtering of lines based on a pattern.
139 * Status column now displays a search match, even if the matched
140 string is scrolled off screen because -S is in effect.
142 * Improve behavior of -F option.
144 * Allow CSI character (0x9B) to work in UTF-8 mode.
146 * Output carriage return at startup in case terminal doesn't default
149 * Fix bug in '' (quote, quote) command after G command.
151 ======================================================================
153 Major changes between "less" versions 416 and 418
155 * Color escape sequences are now supported in WIN32 build.
157 * Makefile now uses EXEEXT feature of autoconf.
159 * Fix search bug when using -R and text contains ANSI color escape sequences.
161 * Fix crash when using -r with UTF-8 text containing 0x9B bytes.
163 * Fix display bug when using ' command to move less than one page forward.
165 * Update GPL to version 3.
167 ======================================================================
169 Major changes between "less" versions 409 and 416
171 * New --follow-name option makes F command follow the name of a file
172 rather than the file descriptor if an open file is renamed.
174 * Make searching with -i/-I work correctly with non-ASCII text.
178 ======================================================================
180 Major changes between "less" versions 406 and 409
182 * Support CSI escape sequences, like SGR escape sequences.
184 * Fix bug which caused screen to fail to repaint when window is resized.
186 * Fix bug in using -i and -I flags with non-ASCII text.
188 * Fix configure bug on systems which don't support langinfo.h.
190 * Fix crash when searching text containing certain invalid UTF-8 sequences.
192 ======================================================================
194 Major changes between "less" versions 394 and 406
196 * Allow decimal point in number for % (percent) command.
198 * Allow decimal point in number for -j option (fraction of screen height).
200 * Make n command fetch previous pattern from history file on first search.
202 * Don't rewrite history file if it has not changed.
204 * Don't move to bottom of screen on first page.
206 * Don't output extraneous newlines, so copy & pasting lines from the
209 * The -c option has been made identical with the -C option.
211 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
212 that no history file should be used.
214 * Search can now find text which follows a null byte, if the PCRE
215 library is used, or if no-regex searching (ctrl-R) is used.
217 * Better compatibility with POSIX more specification.
219 * Make -f work for directories.
221 * Make "t" cmd traverse tags in the correct order.
223 * Allow a few binary characters in the input file before warning
224 that the file is binary.
226 * Don't warn that file is binary if it merely contains ANSI color sequences
229 * Update Unicode character tables.
231 * Support DESTDIR in Makefile.
233 * Fix bug when filename contains certain shell metacharacters such as "$".
235 * Fix bug when resizing the window while waiting for input from a pipe.
237 * Fix configure bugs.
239 ======================================================================
241 Major changes between "less" versions 382 and 394
243 * Add history file to save search and shell command history between
246 * Improve behavior of history list for search and shell commands.
248 * Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
250 * Improve handling of UTF-8 files and commands, including better
251 line wrapping and handling double-width chars.
253 * Added LESSUTFBINFMT environment variable to control display of
254 non-printable characters in a UTF-8 file.
256 * Add --with-secure option to configure, to make it easier to
257 build a secure version of less.
259 * Show search matches in the status column even if search highlights
260 are disabled via the -G option or the ESC-u command.
262 * Improve performance when the file contains very long lines.
264 * Add "windows" charset.
266 * Add man page for lessecho.
268 * Add support for erase2 character, treated same as erase.
270 * Use ASCII lowercase/uppercase logic when operating on the command line.
272 * Update makefile for Borland C++ 5.5.1.
274 * Fix bug in calculating number of pages for %D prompt.
276 * Fix bug in handling tag file error.
278 * Fix obscure bug if input file is deleted while viewing help.
280 * Fix bug handling filenames which include square brackets.
282 * Fix possible buffer overflow in "global" tag search.
284 * Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
286 * Fix buffer overflow in reverse search.
288 ======================================================================
290 Major changes between "less" versions 381 and 382
292 * Removed some old copyrighted code.
293 This probably breaks OS/9 support.
295 ======================================================================
297 Major changes between "less" versions 378 and 381
299 * New -L option to disable LESSOPEN processing.
301 * Further support for large (64 bit) file addressing.
302 Large file support is now set up by the configure script.
305 Replace configure.in, acconfig.h, defines.h.top with configure.ac.
307 * Overstriking underscore with underscore is now bold or underlined
308 depending on context.
310 * Use only 7 spaces for line numbers in -N mode, if possible.
312 * Fix some bugs in handling overstriking in UTF-8 files.
314 * Fix some nroff issues in the man page.
316 ======================================================================
318 Major changes between "less" versions 376 and 378
321 Default buffer space is now 64K as documented.
322 Search highlighting works properly when used with -R.
323 Windows version works properly when input file contains carriage returns.
324 Clean up some compiler warnings.
326 ======================================================================
328 Major changes between "less" versions 358 and 376
330 * -x option can now specify multiple variable-width tab stops.
332 * -X option no longer disables keypad initialization.
333 New option --no-keypad disables keypad initialization.
335 * New commands t and T step through multiple tag matches.
336 Added support for "global(1)" tags
337 (see http://www.gnu.org/software/global/global.html).
339 * New prompt style set by option -Pw defines the message printed
340 while waiting for data in the F command.
342 * System-wide lesskey file now defaults to sysless in etc directory
343 instead of .sysless in bin directory.
344 Use "configure --sysconfdir=..." to change it.
345 (For backwards compatibility, .sysless in bin is still recognized.)
347 * Pressing RightArrow or LeftArrow while entering a number now shifts
348 the display N columns rather than editing the number itself.
350 * Status column (enabled with -J) now shows search results.
352 * Windows version sets window title.
354 * Default LESSCHARSET for MS-DOS versions is now "dos".
356 * Searching works better with ANSI (SGR) escape sequences.
357 ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
359 * Improved performance in reading very large pipes.
361 * Eliminated some dependencies on file offets being 32 bits.
363 * Fixed problems when viewing files with very long lines.
365 * Fixed overstriking in UTF-8 mode, and overstriking tabs.
367 * Improved horizontal shifting of text using -R option with ANSI color.
369 * Improved handling of filenames containing shell metacharacters.
371 * Some fixes for EBCDIC systems.
373 * Some fixes for OS/2 systems.
375 ======================================================================
377 Major changes between "less" versions 354 and 358
379 * Add -J (--status-column) option to display a status column.
381 * Add -# (--shift) option to set default horizontal shift distance.
382 Default horizontal shift distance is now one-half screen width.
384 * Horizontal shifting does not shift line numbers if -N is in effect.
386 * Horizontal shifting acts as though -S were set, to avoid confusion.
388 ======================================================================
391 Major changes between "less" versions 352 and 354
393 * Allow space after numeric-valued command line options.
395 * Fix problem with configuring terminal libraries on some systems.
397 * Add support for PCRE regular expression library.
399 * Add --with-regex option to configure to allow manually selecting
400 a regular expression library.
402 * Fix bug compiling with SECURE = 1.
404 ======================================================================
407 Major changes between "less" versions 346 and 352
409 * Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
411 * Add --with-editor option to configure script.
413 * The -M prompt and = message now show the top and bottom line number.
415 * Fix bug in running the editor on a file whose name contains quotes, etc.
417 * Fix bug in horizontal scrolling of long lines.
419 * Fix bug in doing :d on a file which contains marks.
421 * Fix bug causing cleared lines to sometimes be filled with standout,
422 bold, underline, etc. on certain terminals.
424 * Fixes for MS-DOS (DJGPP) version.
426 ======================================================================
429 Major changes between "less" versions 340 and 346
431 * The UTF-8 character set is now supported.
433 * The default character set is now latin1 rather than ascii.
435 * New option -R (--RAW-CONTROL-CHARS) is like -r but handles
436 long (wrapped) lines correctly, as long as the input contains only
437 normal text and ANSI color escape sequences.
439 * New option -F (--quit-if-one-screen) quits if the text fits on
442 * The -w option now highlights the target line of a g or p command.
444 * A system-wide lesskey file is supported (LESSKEY_SYSTEM).
446 * New escape for prompt strings: %c is replaced by column number.
448 * New escape for prompt strings: %P is replaced by percentage into
449 file, based on line number rather than byte offset.
451 * HOME and END keys now jump to beginning of file or end of file.
453 ======================================================================
456 Major changes between "less" versions 337 and 340
458 * Command line options for less may now be given in either the old
459 single-letter form, or a new long name form (--option-name).
460 See the less man page or "less --help" for the list of long option names.
462 * Command line options for lesskey may now be given in a new long name
463 form. See the lesskey man page for the list of long option names.
465 * New command -- toggles an option using the long option name.
467 * New command __ queries an option using the long option name.
469 * The old -- command is renamed as -!.
471 * If a ^P is entered between the dash and the option letter of the -
472 command, the message describing the new setting is suppressed.
474 * Lesskey files may now contain \k escape sequences to represent the
475 "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
477 * New command :d removes the current file from the list of files.
479 * New option -~ (like -w before version 335)
480 suppresses tildes after end-of-file.
482 * Less is now released under the GNU General Public License.
484 ======================================================================
487 Major changes between "less" versions 335 and 337
489 * Fixed bugs in "make install".
491 ======================================================================
494 Major changes between "less" versions 332 and 335
496 * The old -w flag (suppress tildes after end-of-file) has been removed.
498 * New -w flag highlights the first new line after a forward-screen.
500 * New -W flag highlights the first new line after any forward movement.
502 * Window resize works even if LINES and/or COLUMNS environment
503 variables are incorrect.
505 * New percent escapes for prompt strings:
506 %d is replaced by the page number, and
507 %D is replaced by the number of pages in the file.
509 * Added charsets "iso8859" and "ebcdic".
511 * In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
513 * Fixed some bugs causing incorrect display on DOS/Windows.
515 ======================================================================
518 Major changes between "less" versions 330 and 332
520 * Filenames from the command line are entered into the command history,
521 so UPARROW/DOWNARROW can be used to retrieve them from the :e command.
523 * Now works correctly on Windows when using a scrolling terminal
524 window (buffer larger than display window).
526 * On Windows, now restores the console screen on exit.
527 Use -X to get the old behavior.
529 * Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
531 * Fixed bug on Windows when piping output of an interactive program.
533 * Fixed bug in tags file processing when tags file has DOS-style
534 line terminators (CR/LF).
536 * Fixed compilation problem on OS/2.
538 ======================================================================
541 Major changes between "less" versions 321 and 330
543 * Now supports filenames containing spaces (in double quotes).
544 New option -" can be used to change the quoting characters.
546 * In filename completion, a slash is appended to a directory name.
547 If the environment variable LESSSEPARATOR is set, the value of
548 that variable, rather than a slash, is appended.
550 * LeftArrow and RightArrow are same as ESC-[ and ESC-].
552 * Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
554 * A "quit" command defined in a lesskey file may now have an "extra"
555 string, which is used to return an exit code from less when it quits.
557 * New environment variables LESSMETACHARS and LESSMETAESCAPE provide
558 more control over how less interfaces to the shell.
560 * Ported to Microsoft Visual C compiler for Windows.
562 * Ported to DJGPP compiler for MS-DOS.
566 ======================================================================
569 Major changes between "less" versions 291 and 321
571 * Command line at bottom of screen now scrolls, so it can be longer
572 than the screen width.
574 * New commands ESC-] and ESC-[ scroll the display horizontally.
576 * New command ESC-SPACE scrolls forward a full screen, even if it
579 * Alternate modifiers for search commands: ^N is same as !,
580 ^F is same as @, and ^E is same as *.
582 * New modifier for search commands: ^K means highlight the matches
583 currently on-screen, but don't move to the first match.
585 * New modifier for search commands: ^R means don't use regular
586 expressions in the search.
588 * Environment variable LESSKEY gives name of default lesskey file.
590 * Environment variable LESSSECURE will force less to run in
593 * Command line argument "--" signals that the rest of the arguments
594 are files (not option flags).
596 * Help file (less.hlp) is no longer installed. Help text is now
597 embedded in the less executable itself.
599 * Added -Ph to change the prompt for the help text.
600 Added -Ps to change the default short prompt (same as plain -P).
602 * Ported to the Borland C compiler for MS-DOS.
604 * Ported to Windows 95 & Windows NT.
608 * Ported to GNU Hurd.
610 ======================================================================
613 Major changes between "less" versions 290 and 291
615 * Less environment variables can be specified in lesskey files.
617 * Fixed MS-DOS build.
619 ======================================================================
622 Major changes between "less" versions 278 and 290
624 * Accepts GNU-style options "--help" and "--version".
626 * OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
630 ======================================================================
633 Major changes between "less" versions 252 and 278
635 * A LESSOPEN preprocessor may now pipe the converted file data to less,
636 rather than writing it to a temporary file.
638 * Search pattern highlighting has been fixed. It now highlights
639 reliably, even if a string is split across two screen lines,
642 * The -F flag (which suppress search highlighting) has been changed
643 to -G. A new flag, -g, changes search highlighting to highlight
644 only the string found by the last search command, instead of all
645 strings which match the last search command.
647 * New flag -I acts like -i, but ignores case even if the search
648 pattern contains uppercase letters.
650 * Less now checks for the environment variable VISUAL before EDITOR.
654 ======================================================================
657 Major changes between "less" versions 237 and 252
659 * Changes in line-editing keys:
660 The literal key is now ^V or ^A rather than \ (backslash).
661 Filename completion commands (TAB and ^L) are disabled
662 when typing a search pattern.
664 * Line-editing command keys can be redefined using lesskey.
666 * Lesskey with no input file defaults to $HOME/.lesskey
667 rather than standard input.
669 * New option -V displays version number of less.
671 * New option -V displays version number of lesskey.
673 * Help file less.hlp is now installed by default in /usr/local/share
674 rather than /usr/local/lib.
677 ======================================================================
680 Major changes between "less" versions 170 and 237
682 * By popular demand, text which matches the current search pattern
683 is highlighted. New -F flag disables this feature.
685 * Henry Spencer's regexp.c is now included, for systems which do not
686 have a regular expression library.
687 regexp.c is Copyright (c) 1986 by University of Toronto.
689 * New line-editing keys, including command history (arrow keys) and
690 filename completion (TAB).
692 * Input preprocessor allows modification of input files (e.g. uncompress)
693 via LESSOPEN/LESSCLOSE environment variables.
695 * New -X flag disables sending termcap "ti" and "te" (initialize and
696 deinitialize) strings to the terminal.
698 * Changing -i from within less now correctly affects a subsequent
701 * Searching for underlined or overstruck text now works when the -u
702 flag is in effect, rather than the -i flag.
704 * Use setlocale (LANG and LC_CTYPE environment variables) to determine
705 the character set if LESSCHARSET/LESSCHARDEF are not set.
707 * The default format for displaying binary characters is now standout
708 (reverse video) rather than blinking. This can still be changed by
709 setting the LESSBINFMT environment variable.
711 * Use autoconf installation technology.
715 ********************************
716 Things that may surprise you
717 ********************************
719 * When you enter text at the bottom of the screen (search string,
720 filename, etc.), some keys act different than previously.
721 Specifically, \ (backslash), ESC, TAB, BACKTAB, and control-L
722 now have line editing functions.
724 * Some previous unofficial versions of less were able to display
725 compressed files. The new LESSOPEN/LESSCLOSE feature now provides
726 this functionality in a different way.
728 * Some previous unofficial versions of less provided a -Z flag to
729 set the number of lines of text to retain between full screen scrolls.
730 The -z-n flag (that is, -z with a negative number) provides this
734 ======================================================================
737 Major changes between "less" versions 123 and 170
739 * New option -j allows target lines to be positioned anywhere on screen.
741 * New option -S truncates displayed line at the screen width,
742 rather than wrapping onto the next line.
744 * New option -y limits amount of forward scroll.
746 * New option -T specifies a "tags" file.
748 * Non-printable, non-control characters are displayed in octal.
749 Such characters, as well as control characters, are displayed
752 * New command -+ sets an option to its default.
753 * New command -- sets an option to the opposite of its default.
755 * Lesskey file may have a string appended to a key's action,
756 which acts as though typed in after the command.
758 * New commands ESC-^F and ESC-^B match arbitrary types of brackets.
760 * New command F monitors a growing file (like "tail -f").
762 * New command | pipes a section of the input file into a shell command.
764 * New command :x directly jumps to a file in the command line list.
766 * Search commands have been enhanced and reorganized:
767 n Repeat search, same direction.
768 N Repeat search, opposite direction.
769 ESC-/ Search forward thru file boundaries
770 ESC-? Search backward thru file boundaries
771 ESC-n Repeat search thru file boundaries, same direction.
772 ESC-N Repeat search thru file boundaries, opposite direction.
773 Special character * causes search to search thru file boundaries.
774 Special character @ causes search to begin at start/end of file list.
776 * Examining a new file adds it to the command line list.
777 A list of files, or an expression which matches more than one file,
778 may be examined; all of them are added to the command line list.
780 * Environment variables LESSCHARSET and LESSCHARDEF can define
781 a non-ASCII character set.
783 * Partial support for MSDOS, including options -R for repainting screen
784 on quit, -v/-V to select video mode, and -W to change window size.
787 ======================================================================
790 Major changes between "less" versions 97 and 123
792 * New option (-N) causes line numbers to be displayed in the
793 text of the file (like vi "set nu").
795 * New option (-?) prints help message immediately.
797 * New option (-r) displays "raw" control characters, without
798 mapping them to ^X notation.
800 * New option (-f) forces less to open non-regular files
803 * New option (-k) can be used to specify lesskey files by name.
805 * New option (-y) can be used to set a forward scroll limit
806 (like -h sets a backward scroll limit).
808 * File marks (set by the m command) are now preserved when a new
809 file is edited. The ' command can thus be used to switch files.
811 * New command ESC-/ searches all files (on the command line)
814 * New command ESC-n repeats previous search, spanning files.
816 * The N command has been changed to repeat the previous search
817 in the reverse direction. The old N command is still available
820 * New command ESC-N repeats previous search in the reverse
821 direction and spanning files.
823 * 8 bit characters are now supported. A new option (-g) can be
824 used to strip off the eighth bit (the previous behavior).
826 * Options which take a following string (like -t) may now
827 optionally have a space between the option letter and the string.
829 * Six new commands { } ( ) [ and ] can be used to match
830 brackets of specific types, similar to vi % command.
832 * New commands z and w move forward/backward one window and
833 simultaneously set the window size.
835 * Prompt string expansion now has %L for line number of the last
836 line in the file, and %E for the name of the editor.
837 Also, % escapes which refer to a line (b=bottom, t=top, etc.)
838 can use j for the jump target line.
840 * New environment variable LESSEDIT can be used to tailor the
841 command string passed to the editor by the v command.
843 * Examining a file which was previously examined will return
844 to the same position in the file.
846 * A "%" is expanded to the current filename and a "#" to the
847 previous filename, in both shell commands and the E command.
848 (Previously % worked only in shell commands and # worked
849 only in the E command.)
851 * New command ":ta" is equivalent to "-t".
853 * New command "s" is equivalent to "-l".
855 * The - command may be followed by "+X" to revert to the default
856 for option X, or "-X" to get the opposite of the default.
858 * Lesskey files may now include characters after the action as
859 extra input to be parsed after the action; for example:
860 "toggle-option X" to toggle a specific option X.