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 453
16 * Allow backslash escaping of metacharacters in LESS environment variable.
18 * Don't quit if syntax errors are found in command line options.
20 * Increase sizes of some internal buffers.
22 * Fix configure bug with --with-regex=none.
24 * Fix crash with "stty rows 0".
26 * Fix Win32 attribute display bug.
28 ======================================================================
30 Major changes between "less" versions 444 and 451
32 * Add ESC-F command to keep reading data until a pattern is found.
34 * Use exit code of LESSOPEN script if LESSOPEN starts with "||".
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.
39 * Add support for GNU regex.
41 * Add configure option --with-regex=none and fix compile errors
42 when compiling with no regex library.
44 * Fix bugs handling SGR sequences in Win32.
46 * Fix possible crashes caused by malformed LESSOPEN or
49 * Fix bug highlighting text which is discontiguous in the file
50 due to backspace processing.
52 * Fix bug in displaying status column when scrolling backwards
53 with -J and -S in effect.
55 ======================================================================
57 Major changes between "less" versions 443 and 444
59 * Fix bug in unget handling that can cause strange effects on the
62 * Remove vestiges of obsolete -l option that can cause a crash.
64 ======================================================================
66 Major changes between "less" versions 436 and 443
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.
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.
75 * Add %F formatting to prompt strings, replaced by the last component
78 * Control-G while editing a command exits the command.
80 * Less now exits with status 2 if control-C is pressed and -K is in effect.
82 * Fix "ungetc overflow" when passing long commands via the -p option.
84 * Fix bug in using line filtering via the & command
85 in combination with -i and -I.
87 * Fix bug in handling negative arguments to the -j option.
89 * Fix bug in handling %t in prompt strings.
91 * Improve handling of long option names.
93 * Improve percentage calculation for very large files.
95 ======================================================================
97 Major changes between "less" versions 429 and 436
99 * Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
101 * Allow a fraction as the argument to the -# (--shift) option.
103 * Fix highlight bug when underlined/overstruck text matches at end of line.
105 * Fix non-regex searches with ctrl-R.
107 ======================================================================
109 Major changes between "less" versions 424 and 429
111 * LESSOPEN pipe will now be used on standard input, if the LESSOPEN
112 environment variable begins with "|-".
114 * The -D option with one number now means use the normal background color.
116 * Don't change permissions on history file if it is not a regular file.
118 * Fix non-ANSI-compliant code that caused problems with some compilers.
120 * Fix binary file detection in UTF-8 mode.
122 * Fix display problems with long lines on "ignaw" terminals.
124 * Fix problem interrupting the line number calculation for initial prompt.
126 * Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
128 * Fix highlight bug when searching for underlined/overstruck text.
130 ======================================================================
132 Major changes between "less" versions 418 and 424
134 * New "&" command allows filtering of lines based on a pattern.
136 * Status column now displays a search match, even if the matched
137 string is scrolled off screen because -S is in effect.
139 * Improve behavior of -F option.
141 * Allow CSI character (0x9B) to work in UTF-8 mode.
143 * Output carriage return at startup in case terminal doesn't default
146 * Fix bug in '' (quote, quote) command after G command.
148 ======================================================================
150 Major changes between "less" versions 416 and 418
152 * Color escape sequences are now supported in WIN32 build.
154 * Makefile now uses EXEEXT feature of autoconf.
156 * Fix search bug when using -R and text contains ANSI color escape sequences.
158 * Fix crash when using -r with UTF-8 text containing 0x9B bytes.
160 * Fix display bug when using ' command to move less than one page forward.
162 * Update GPL to version 3.
164 ======================================================================
166 Major changes between "less" versions 409 and 416
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.
171 * Make searching with -i/-I work correctly with non-ASCII text.
175 ======================================================================
177 Major changes between "less" versions 406 and 409
179 * Support CSI escape sequences, like SGR escape sequences.
181 * Fix bug which caused screen to fail to repaint when window is resized.
183 * Fix bug in using -i and -I flags with non-ASCII text.
185 * Fix configure bug on systems which don't support langinfo.h.
187 * Fix crash when searching text containing certain invalid UTF-8 sequences.
189 ======================================================================
191 Major changes between "less" versions 394 and 406
193 * Allow decimal point in number for % (percent) command.
195 * Allow decimal point in number for -j option (fraction of screen height).
197 * Make n command fetch previous pattern from history file on first search.
199 * Don't rewrite history file if it has not changed.
201 * Don't move to bottom of screen on first page.
203 * Don't output extraneous newlines, so copy & pasting lines from the
206 * The -c option has been made identical with the -C option.
208 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
209 that no history file should be used.
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.
214 * Better compatibility with POSIX more specification.
216 * Make -f work for directories.
218 * Make "t" cmd traverse tags in the correct order.
220 * Allow a few binary characters in the input file before warning
221 that the file is binary.
223 * Don't warn that file is binary if it merely contains ANSI color sequences
226 * Update Unicode character tables.
228 * Support DESTDIR in Makefile.
230 * Fix bug when filename contains certain shell metacharacters such as "$".
232 * Fix bug when resizing the window while waiting for input from a pipe.
234 * Fix configure bugs.
236 ======================================================================
238 Major changes between "less" versions 382 and 394
240 * Add history file to save search and shell command history between
243 * Improve behavior of history list for search and shell commands.
245 * Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
247 * Improve handling of UTF-8 files and commands, including better
248 line wrapping and handling double-width chars.
250 * Added LESSUTFBINFMT environment variable to control display of
251 non-printable characters in a UTF-8 file.
253 * Add --with-secure option to configure, to make it easier to
254 build a secure version of less.
256 * Show search matches in the status column even if search highlights
257 are disabled via the -G option or the ESC-u command.
259 * Improve performance when the file contains very long lines.
261 * Add "windows" charset.
263 * Add man page for lessecho.
265 * Add support for erase2 character, treated same as erase.
267 * Use ASCII lowercase/uppercase logic when operating on the command line.
269 * Update makefile for Borland C++ 5.5.1.
271 * Fix bug in calculating number of pages for %D prompt.
273 * Fix bug in handling tag file error.
275 * Fix obscure bug if input file is deleted while viewing help.
277 * Fix bug handling filenames which include square brackets.
279 * Fix possible buffer overflow in "global" tag search.
281 * Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
283 * Fix buffer overflow in reverse search.
285 ======================================================================
287 Major changes between "less" versions 381 and 382
289 * Removed some old copyrighted code.
290 This probably breaks OS/9 support.
292 ======================================================================
294 Major changes between "less" versions 378 and 381
296 * New -L option to disable LESSOPEN processing.
298 * Further support for large (64 bit) file addressing.
299 Large file support is now set up by the configure script.
302 Replace configure.in, acconfig.h, defines.h.top with configure.ac.
304 * Overstriking underscore with underscore is now bold or underlined
305 depending on context.
307 * Use only 7 spaces for line numbers in -N mode, if possible.
309 * Fix some bugs in handling overstriking in UTF-8 files.
311 * Fix some nroff issues in the man page.
313 ======================================================================
315 Major changes between "less" versions 376 and 378
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.
323 ======================================================================
325 Major changes between "less" versions 358 and 376
327 * -x option can now specify multiple variable-width tab stops.
329 * -X option no longer disables keypad initialization.
330 New option --no-keypad disables keypad initialization.
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).
336 * New prompt style set by option -Pw defines the message printed
337 while waiting for data in the F command.
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.)
344 * Pressing RightArrow or LeftArrow while entering a number now shifts
345 the display N columns rather than editing the number itself.
347 * Status column (enabled with -J) now shows search results.
349 * Windows version sets window title.
351 * Default LESSCHARSET for MS-DOS versions is now "dos".
353 * Searching works better with ANSI (SGR) escape sequences.
354 ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
356 * Improved performance in reading very large pipes.
358 * Eliminated some dependencies on file offets being 32 bits.
360 * Fixed problems when viewing files with very long lines.
362 * Fixed overstriking in UTF-8 mode, and overstriking tabs.
364 * Improved horizontal shifting of text using -R option with ANSI color.
366 * Improved handling of filenames containing shell metacharacters.
368 * Some fixes for EBCDIC systems.
370 * Some fixes for OS/2 systems.
372 ======================================================================
374 Major changes between "less" versions 354 and 358
376 * Add -J (--status-column) option to display a status column.
378 * Add -# (--shift) option to set default horizontal shift distance.
379 Default horizontal shift distance is now one-half screen width.
381 * Horizontal shifting does not shift line numbers if -N is in effect.
383 * Horizontal shifting acts as though -S were set, to avoid confusion.
385 ======================================================================
388 Major changes between "less" versions 352 and 354
390 * Allow space after numeric-valued command line options.
392 * Fix problem with configuring terminal libraries on some systems.
394 * Add support for PCRE regular expression library.
396 * Add --with-regex option to configure to allow manually selecting
397 a regular expression library.
399 * Fix bug compiling with SECURE = 1.
401 ======================================================================
404 Major changes between "less" versions 346 and 352
406 * Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
408 * Add --with-editor option to configure script.
410 * The -M prompt and = message now show the top and bottom line number.
412 * Fix bug in running the editor on a file whose name contains quotes, etc.
414 * Fix bug in horizontal scrolling of long lines.
416 * Fix bug in doing :d on a file which contains marks.
418 * Fix bug causing cleared lines to sometimes be filled with standout,
419 bold, underline, etc. on certain terminals.
421 * Fixes for MS-DOS (DJGPP) version.
423 ======================================================================
426 Major changes between "less" versions 340 and 346
428 * The UTF-8 character set is now supported.
430 * The default character set is now latin1 rather than ascii.
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.
436 * New option -F (--quit-if-one-screen) quits if the text fits on
439 * The -w option now highlights the target line of a g or p command.
441 * A system-wide lesskey file is supported (LESSKEY_SYSTEM).
443 * New escape for prompt strings: %c is replaced by column number.
445 * New escape for prompt strings: %P is replaced by percentage into
446 file, based on line number rather than byte offset.
448 * HOME and END keys now jump to beginning of file or end of file.
450 ======================================================================
453 Major changes between "less" versions 337 and 340
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.
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.
462 * New command -- toggles an option using the long option name.
464 * New command __ queries an option using the long option name.
466 * The old -- command is renamed as -!.
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.
471 * Lesskey files may now contain \k escape sequences to represent the
472 "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
474 * New command :d removes the current file from the list of files.
476 * New option -~ (like -w before version 335)
477 suppresses tildes after end-of-file.
479 * Less is now released under the GNU General Public License.
481 ======================================================================
484 Major changes between "less" versions 335 and 337
486 * Fixed bugs in "make install".
488 ======================================================================
491 Major changes between "less" versions 332 and 335
493 * The old -w flag (suppress tildes after end-of-file) has been removed.
495 * New -w flag highlights the first new line after a forward-screen.
497 * New -W flag highlights the first new line after any forward movement.
499 * Window resize works even if LINES and/or COLUMNS environment
500 variables are incorrect.
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.
506 * Added charsets "iso8859" and "ebcdic".
508 * In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
510 * Fixed some bugs causing incorrect display on DOS/Windows.
512 ======================================================================
515 Major changes between "less" versions 330 and 332
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.
520 * Now works correctly on Windows when using a scrolling terminal
521 window (buffer larger than display window).
523 * On Windows, now restores the console screen on exit.
524 Use -X to get the old behavior.
526 * Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
528 * Fixed bug on Windows when piping output of an interactive program.
530 * Fixed bug in tags file processing when tags file has DOS-style
531 line terminators (CR/LF).
533 * Fixed compilation problem on OS/2.
535 ======================================================================
538 Major changes between "less" versions 321 and 330
540 * Now supports filenames containing spaces (in double quotes).
541 New option -" can be used to change the quoting characters.
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.
547 * LeftArrow and RightArrow are same as ESC-[ and ESC-].
549 * Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
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.
554 * New environment variables LESSMETACHARS and LESSMETAESCAPE provide
555 more control over how less interfaces to the shell.
557 * Ported to Microsoft Visual C compiler for Windows.
559 * Ported to DJGPP compiler for MS-DOS.
563 ======================================================================
566 Major changes between "less" versions 291 and 321
568 * Command line at bottom of screen now scrolls, so it can be longer
569 than the screen width.
571 * New commands ESC-] and ESC-[ scroll the display horizontally.
573 * New command ESC-SPACE scrolls forward a full screen, even if it
576 * Alternate modifiers for search commands: ^N is same as !,
577 ^F is same as @, and ^E is same as *.
579 * New modifier for search commands: ^K means highlight the matches
580 currently on-screen, but don't move to the first match.
582 * New modifier for search commands: ^R means don't use regular
583 expressions in the search.
585 * Environment variable LESSKEY gives name of default lesskey file.
587 * Environment variable LESSSECURE will force less to run in
590 * Command line argument "--" signals that the rest of the arguments
591 are files (not option flags).
593 * Help file (less.hlp) is no longer installed. Help text is now
594 embedded in the less executable itself.
596 * Added -Ph to change the prompt for the help text.
597 Added -Ps to change the default short prompt (same as plain -P).
599 * Ported to the Borland C compiler for MS-DOS.
601 * Ported to Windows 95 & Windows NT.
605 * Ported to GNU Hurd.
607 ======================================================================
610 Major changes between "less" versions 290 and 291
612 * Less environment variables can be specified in lesskey files.
614 * Fixed MS-DOS build.
616 ======================================================================
619 Major changes between "less" versions 278 and 290
621 * Accepts GNU-style options "--help" and "--version".
623 * OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
627 ======================================================================
630 Major changes between "less" versions 252 and 278
632 * A LESSOPEN preprocessor may now pipe the converted file data to less,
633 rather than writing it to a temporary file.
635 * Search pattern highlighting has been fixed. It now highlights
636 reliably, even if a string is split across two screen lines,
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.
644 * New flag -I acts like -i, but ignores case even if the search
645 pattern contains uppercase letters.
647 * Less now checks for the environment variable VISUAL before EDITOR.
651 ======================================================================
654 Major changes between "less" versions 237 and 252
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.
661 * Line-editing command keys can be redefined using lesskey.
663 * Lesskey with no input file defaults to $HOME/.lesskey
664 rather than standard input.
666 * New option -V displays version number of less.
668 * New option -V displays version number of lesskey.
670 * Help file less.hlp is now installed by default in /usr/local/share
671 rather than /usr/local/lib.
674 ======================================================================
677 Major changes between "less" versions 170 and 237
679 * By popular demand, text which matches the current search pattern
680 is highlighted. New -F flag disables this feature.
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.
686 * New line-editing keys, including command history (arrow keys) and
687 filename completion (TAB).
689 * Input preprocessor allows modification of input files (e.g. uncompress)
690 via LESSOPEN/LESSCLOSE environment variables.
692 * New -X flag disables sending termcap "ti" and "te" (initialize and
693 deinitialize) strings to the terminal.
695 * Changing -i from within less now correctly affects a subsequent
698 * Searching for underlined or overstruck text now works when the -u
699 flag is in effect, rather than the -i flag.
701 * Use setlocale (LANG and LC_CTYPE environment variables) to determine
702 the character set if LESSCHARSET/LESSCHARDEF are not set.
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.
708 * Use autoconf installation technology.
712 ********************************
713 Things that may surprise you
714 ********************************
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.
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.
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
731 ======================================================================
734 Major changes between "less" versions 123 and 170
736 * New option -j allows target lines to be positioned anywhere on screen.
738 * New option -S truncates displayed line at the screen width,
739 rather than wrapping onto the next line.
741 * New option -y limits amount of forward scroll.
743 * New option -T specifies a "tags" file.
745 * Non-printable, non-control characters are displayed in octal.
746 Such characters, as well as control characters, are displayed
749 * New command -+ sets an option to its default.
750 * New command -- sets an option to the opposite of its default.
752 * Lesskey file may have a string appended to a key's action,
753 which acts as though typed in after the command.
755 * New commands ESC-^F and ESC-^B match arbitrary types of brackets.
757 * New command F monitors a growing file (like "tail -f").
759 * New command | pipes a section of the input file into a shell command.
761 * New command :x directly jumps to a file in the command line list.
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.
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.
777 * Environment variables LESSCHARSET and LESSCHARDEF can define
778 a non-ASCII character set.
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.
784 ======================================================================
787 Major changes between "less" versions 97 and 123
789 * New option (-N) causes line numbers to be displayed in the
790 text of the file (like vi "set nu").
792 * New option (-?) prints help message immediately.
794 * New option (-r) displays "raw" control characters, without
795 mapping them to ^X notation.
797 * New option (-f) forces less to open non-regular files
800 * New option (-k) can be used to specify lesskey files by name.
802 * New option (-y) can be used to set a forward scroll limit
803 (like -h sets a backward scroll limit).
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.
808 * New command ESC-/ searches all files (on the command line)
811 * New command ESC-n repeats previous search, spanning files.
813 * The N command has been changed to repeat the previous search
814 in the reverse direction. The old N command is still available
817 * New command ESC-N repeats previous search in the reverse
818 direction and spanning files.
820 * 8 bit characters are now supported. A new option (-g) can be
821 used to strip off the eighth bit (the previous behavior).
823 * Options which take a following string (like -t) may now
824 optionally have a space between the option letter and the string.
826 * Six new commands { } ( ) [ and ] can be used to match
827 brackets of specific types, similar to vi % command.
829 * New commands z and w move forward/backward one window and
830 simultaneously set the window size.
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.
837 * New environment variable LESSEDIT can be used to tailor the
838 command string passed to the editor by the v command.
840 * Examining a file which was previously examined will return
841 to the same position in the file.
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.)
848 * New command ":ta" is equivalent to "-t".
850 * New command "s" is equivalent to "-l".
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.
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.