1 This is a terse description of the new features added to bash-4.1 since
2 the release of bash-4.0. As always, the manual page (doc/bash.1) is
3 the place to look for complete descriptions.
5 1. New Features in Bash
7 a. Here-documents within $(...) command substitutions may once more be
8 delimited by the closing right paren, instead of requiring a newline.
10 b. Bash's file status checks (executable, readable, etc.) now take file
11 system ACLs into account on file systems that support them.
13 c. Bash now passes environment variables with names that are not valid
14 shell variable names through into the environment passed to child
17 d. The `execute-unix-command' readline function now attempts to clear and
18 reuse the current line rather than move to a new one after the command
21 e. `printf -v' can now assign values to array indices.
23 f. New `complete -E' and `compopt -E' options that work on the "empty"
24 completion: completion attempted on an empty command line.
26 g. New complete/compgen/compopt -D option to define a `default' completion:
27 a completion to be invoked on command for which no completion has been
28 defined. If this function returns 124, programmable completion is
29 attempted again, allowing a user to dynamically build a set of completions
30 as completion is attempted by having the default completion function
31 install individual completion functions each time it is invoked.
33 h. When displaying associative arrays, subscripts are now quoted.
35 i. Changes to dabbrev-expand to make it more `emacs-like': no space appended
36 after matches, completions are not sorted, and most recent history entries
39 j. The [[ and (( commands are now subject to the setting of `set -e' and the
42 k. The source/. builtin now removes NUL bytes from the file before attempting
45 l. There is a new configuration option (in config-top.h) that forces bash to
46 forward all history entries to syslog.
48 m. A new variable $BASHOPTS to export shell options settable using `shopt' to
51 n. There is a new confgure option that forces the extglob option to be
54 o. New variable $BASH_XTRACEFD; when set to an integer bash will write xtrace
55 output to that file descriptor.
57 p. If the optional left-hand-side of a redirection is of the form {var}, the
58 shell assigns the file descriptor used to $var or uses $var as the file
59 descriptor to move or close, depending on the redirection operator.
61 q. The < and > operators to the [[ conditional command now do string
62 comparison according to the current locale if the compatibility level
65 r. Programmable completion now uses the completion for `b' instead of `a'
66 when completion is attempted on a line like: a $(b c.
68 s. Force extglob on temporarily when parsing the pattern argument to
69 the == and != operators to the [[ command, for compatibility.
71 t. Changed the behavior of interrupting the wait builtin when a SIGCHLD is
72 received and a trap on SIGCHLD is set to be Posix-mode only.
74 u. The read builtin has a new `-N nchars' option, which reads exactly NCHARS
75 characters, ignoring delimiters like newline.
77 v. The mapfile/readarray builtin no longer stores the commands it invokes via
78 callbacks in the history list.
80 w. There is a new `compat40' shopt option.
82 2. New Features in Readline
84 a. New bindable function: menu-complete-backward.
86 b. In the vi insertion keymap, C-n is now bound to menu-complete by default,
87 and C-p to menu-complete-backward.
89 c. When in vi command mode, repeatedly hitting ESC now does nothing, even
90 when ESC introduces a bound key sequence. This is closer to how
91 historical vi behaves.
93 d. New bindable function: skip-csi-sequence. Can be used as a default to
94 consume key sequences generated by keys like Home and End without having
97 e. New application-settable function: rl_filename_rewrite_hook. Can be used
98 to rewite or modify filenames read from the file system before they are
99 compared to the word to be completed.
101 f. New bindable variable: skip-completed-text, active when completing in the
102 middle of a word. If enabled, it means that characters in the completion
103 that match characters in the remainder of the word are "skipped" rather
104 than inserted into the line.
106 g. The pre-readline-6.0 version of menu completion is available as
107 "old-menu-complete" for users who do not like the readline-6.0 version.
109 h. New bindable variable: echo-control-characters. If enabled, and the
110 tty ECHOCTL bit is set, controls the echoing of characters corresponding
111 to keyboard-generated signals.
113 i. New bindable variable: enable-meta-key. Controls whether or not readline
114 sends the smm/rmm sequences if the terminal indicates it has a meta key
115 that enables eight-bit characters.
117 -------------------------------------------------------------------------------
118 This is a terse description of the new features added to bash-4.0 since
119 the release of bash-3.2. As always, the manual page (doc/bash.1) is
120 the place to look for complete descriptions.
122 1. New Features in Bash
124 a. When using substring expansion on the positional parameters, a starting
125 index of 0 now causes $0 to be prefixed to the list.
127 b. The `help' builtin now prints its columns with entries sorted vertically
128 rather than horizontally.
130 c. There is a new variable, $BASHPID, which always returns the process id of
133 d. There is a new `autocd' option that, when enabled, causes bash to attempt
134 to `cd' to a directory name that is supplied as the first word of a
137 e. There is a new `checkjobs' option that causes the shell to check for and
138 report any running or stopped jobs at exit.
140 f. The programmable completion code exports a new COMP_TYPE variable, set to
141 a character describing the type of completion being attempted.
143 g. The programmable completion code exports a new COMP_KEY variable, set to
144 the character that caused the completion to be invoked (e.g., TAB).
146 h. If creation of a child process fails due to insufficient resources, bash
147 will try again several times before reporting failure.
149 i. The programmable completion code now uses the same set of characters as
150 readline when breaking the command line into a list of words.
152 j. The block multiplier for the ulimit -c and -f options is now 512 when in
153 Posix mode, as Posix specifies.
155 k. Changed the behavior of the read builtin to save any partial input received
156 in the specified variable when the read builtin times out. This also
157 results in variables specified as arguments to read to be set to the empty
158 string when there is no input available. When the read builtin times out,
159 it returns an exit status greater than 128.
161 l. The shell now has the notion of a `compatibility level', controlled by
162 new variables settable by `shopt'. Setting this variable currently
163 restores the bash-3.1 behavior when processing quoted strings on the rhs
164 of the `=~' operator to the `[[' command.
166 m. The `ulimit' builtin now has new -b (socket buffer size) and -T (number
169 n. The -p option to `declare' now displays all variable values and attributes
170 (or function values and attributes if used with -f).
172 o. There is a new `compopt' builtin that allows completion functions to modify
173 completion options for existing completions or the completion currently
176 p. The `read' builtin has a new -i option which inserts text into the reply
177 buffer when using readline.
179 q. A new `-E' option to the complete builtin allows control of the default
180 behavior for completion on an empty line.
182 r. There is now limited support for completing command name words containing
185 s. Changed format of internal help documentation for all builtins to roughly
186 follow man page format.
188 t. The `help' builtin now has a new -d option, to display a short description,
189 and a -m option, to print help information in a man page-like format.
191 u. There is a new `mapfile' builtin to populate an array with lines from a
192 given file. The name `readarray' is a synonym.
194 v. If a command is not found, the shell attempts to execute a shell function
195 named `command_not_found_handle', supplying the command words as the
198 w. There is a new shell option: `globstar'. When enabled, the globbing code
199 treats `**' specially -- it matches all directories (and files within
200 them, when appropriate) recursively.
202 x. There is a new shell option: `dirspell'. When enabled, the filename
203 completion code performs spelling correction on directory names during
206 y. The `-t' option to the `read' builtin now supports fractional timeout
209 z. Brace expansion now allows zero-padding of expanded numeric values and
210 will add the proper number of zeroes to make sure all values contain the
211 same number of digits.
213 aa. There is a new bash-specific bindable readline function: `dabbrev-expand'.
214 It uses menu completion on a set of words taken from the history list.
216 bb. The command assigned to a key sequence with `bind -x' now sets two new
217 variables in the environment of the executed command: READLINE_LINE_BUFFER
218 and READLINE_POINT. The command can change the current readline line
219 and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT,
222 cc. There is a new &>> redirection operator, which appends the standard output
223 and standard error to the named file.
225 dd. The parser now understands `|&' as a synonym for `2>&1 |', which redirects
226 the standard error for a command through a pipe.
228 ee. The new `;&' case statement action list terminator causes execution to
229 continue with the action associated with the next pattern in the
230 statement rather than terminating the command.
232 ff. The new `;;&' case statement action list terminator causes the shell to
233 test the next set of patterns after completing execution of the current
234 action, rather than terminating the command.
236 gg. The shell understands a new variable: PROMPT_DIRTRIM. When set to an
237 integer value greater than zero, prompt expansion of \w and \W will
238 retain only that number of trailing pathname components and replace
239 the intervening characters with `...'.
241 hh. There are new case-modifying word expansions: uppercase (^[^]) and
242 lowercase (,[,]). They can work on either the first character or
243 array element, or globally. They accept an optional shell pattern
244 that determines which characters to modify. There is an optionally-
245 configured feature to include capitalization operators.
247 ii. The shell provides associative array variables, with the appropriate
248 support to create, delete, assign values to, and expand them.
250 jj. The `declare' builtin now has new -l (convert value to lowercase upon
251 assignment) and -u (convert value to uppercase upon assignment) options.
252 There is an optionally-configurable -c option to capitalize a value at
255 kk. There is a new `coproc' reserved word that specifies a coprocess: an
256 asynchronous command run with two pipes connected to the creating shell.
257 Coprocs can be named. The input and output file descriptors and the
258 PID of the coprocess are available to the calling shell in variables
259 with coproc-specific names.
261 ll. A value of 0 for the -t option to `read' now returns success if there is
262 input available to be read from the specified file descriptor.
264 mm. CDPATH and GLOBIGNORE are ignored when the shell is running in privileged
267 nn. New bindable readline functions shell-forward-word and shell-backward-word,
268 which move forward and backward words delimited by shell metacharacters
269 and honor shell quoting.
271 oo. New bindable readline functions shell-backward-kill-word and shell-kill-word
272 which kill words backward and forward, but use the same word boundaries
273 as shell-forward-word and shell-backward-word.
275 2. New Features in Readline
277 a. A new variable, rl_sort_completion_matches; allows applications to inhibit
278 match list sorting (but beware: some things don't work right if
279 applications do this).
281 b. A new variable, rl_completion_invoking_key; allows applications to discover
282 the key that invoked rl_complete or rl_menu_complete.
284 c. The functions rl_block_sigint and rl_release_sigint are now public and
285 available to calling applications who want to protect critical sections
288 d. The functions rl_save_state and rl_restore_state are now public and
289 available to calling applications; documented rest of readline's state
292 e. A new user-settable variable, `history-size', allows setting the maximum
293 number of entries in the history list.
295 f. There is a new implementation of menu completion, with several improvements
296 over the old; the most notable improvement is a better `completions
299 g. The menu completion code now uses the rl_menu_completion_entry_function
300 variable, allowing applications to provide their own menu completion
303 h. There is support for replacing a prefix of a pathname with a `...' when
304 displaying possible completions. This is controllable by setting the
305 `completion-prefix-display-length' variable. Matches with a common prefix
306 longer than this value have the common prefix replaced with `...'.
308 i. There is a new `revert-all-at-newline' variable. If enabled, readline will
309 undo all outstanding changes to all history lines when `accept-line' is
312 j. If the kernel supports it, readline displays special characters
313 corresponding to a keyboard-generated signal when the signal is received.
315 -------------------------------------------------------------------------------
316 This is a terse description of the new features added to bash-3.2 since
317 the release of bash-3.1. As always, the manual page (doc/bash.1) is
318 the place to look for complete descriptions.
320 1. New Features in Bash
322 a. Changed the parameter pattern replacement functions to not anchor the
323 pattern at the beginning of the string if doing global replacement - that
324 combination doesn't make any sense.
326 b. When running in `word expansion only' mode (--wordexp option), inhibit
327 process substitution.
329 c. Loadable builtins now work on MacOS X 10.[34].
331 d. Shells running in posix mode no longer set $HOME, as POSIX requires.
333 e. The code that checks for binary files being executed as shell scripts now
334 checks only for NUL rather than any non-printing character.
336 f. Quoting the string argument to the [[ command's =~ operator now forces
337 string matching, as with the other pattern-matching operators.
339 2. New Features in Readline
341 a. Calling applications can now set the keyboard timeout to 0, allowing
344 b. The value of SYS_INPUTRC (configurable at compilation time) is now used as
345 the default last-ditch startup file.
347 c. The history file reading functions now allow windows-like \r\n line
350 -------------------------------------------------------------------------------
351 This is a terse description of the new features added to bash-3.1 since
352 the release of bash-3.0. As always, the manual page (doc/bash.1) is
353 the place to look for complete descriptions.
355 1. New Features in Bash
357 a. Bash now understands LC_TIME as a special variable so that time display
358 tracks the current locale.
360 b. BASH_ARGC, BASH_ARGV, BASH_SOURCE, and BASH_LINENO are no longer created
361 as `invisible' variables and may not be unset.
363 c. In POSIX mode, if `xpg_echo' option is enabled, the `echo' builtin doesn't
364 try to interpret any options at all, as POSIX requires.
366 d. The `bg' builtin now accepts multiple arguments, as POSIX seems to specify.
368 e. Fixed vi-mode word completion and glob expansion to perform tilde
371 f. The `**' mathematic exponentiation operator is now right-associative.
373 g. The `ulimit' builtin has new options: -i (max number of pending signals),
374 -q (max size of POSIX message queues), and -x (max number of file locks).
376 h. A bare `%' once again expands to the current job when used as a job
379 i. The `+=' assignment operator (append to the value of a string or array) is
380 now supported for assignment statements and arguments to builtin commands
381 that accept assignment statements.
383 j. BASH_COMMAND now preserves its value when a DEBUG trap is executed.
385 k. The `gnu_errfmt' option is enabled automatically if the shell is running
386 in an emacs terminal window.
388 l. New configuration option: --single-help-strings. Causes long help text
389 to be written as a single string; intended to ease translation.
391 m. The COMP_WORDBREAKS variable now causes the list of word break characters
392 to be emptied when the variable is unset.
394 n. An unquoted expansion of $* when $IFS is empty now causes the positional
395 parameters to be concatenated if the expansion doesn't undergo word
398 o. Bash now inherits $_ from the environment if it appears there at startup.
400 p. New shell option: nocasematch. If non-zero, shell pattern matching ignores
401 case when used by `case' and `[[' commands.
403 q. The `printf' builtin takes a new option: -v var. That causes the output
404 to be placed into var instead of on stdout.
406 r. By default, the shell no longer reports processes dying from SIGPIPE.
408 s. Bash now sets the extern variable `environ' to the export environment it
409 creates, so C library functions that call getenv() (and can't use the
410 shell-provided replacement) get current values of environment variables.
412 t. A new configuration option, `--enable-strict-posix-default', which will
413 build bash to be POSIX conforming by default.
415 u. If compiled for strict POSIX conformance, LINES and COLUMNS may now
416 override the true terminal size.
418 2. New Features in Readline
420 a. The key sequence sent by the keypad `delete' key is now automatically
421 bound to delete-char.
423 b. A negative argument to menu-complete now cycles backward through the
426 c. A new bindable readline variable: bind-tty-special-chars. If non-zero,
427 readline will bind the terminal special characters to their readline
428 equivalents when it's called (on by default).
430 d. New bindable command: vi-rubout. Saves deleted text for possible
431 reinsertion, as with any vi-mode `text modification' command; `X' is bound
432 to this in vi command mode.
434 e. A new external application-controllable variable that allows the LINES
435 and COLUMNS environment variables to set the window size regardless of
436 what the kernel returns: rl_prefer_env_winsize
438 -------------------------------------------------------------------------------
439 This is a terse description of the new features added to bash-3.0 since
440 the release of bash-2.05b. As always, the manual page (doc/bash.1) is
441 the place to look for complete descriptions.
443 1. New Features in Bash
445 a. ANSI string expansion now implements the \x{hexdigits} escape.
447 b. There is a new loadable `strftime' builtin.
449 c. New variable, COMP_WORDBREAKS, which controls the readline completer's
450 idea of word break characters.
452 d. The `type' builtin no longer reports on aliases unless alias expansion
453 will actually be performed.
455 e. HISTCONTROL is now a colon-separated list of values, which permits
456 more extensibility and backwards compatibility.
458 f. HISTCONTROL may now include the `erasedups' option, which causes all lines
459 matching a line being added to be removed from the history list.
461 g. `configure' has a new `--enable-multibyte' argument that permits multibyte
462 character support to be disabled even on systems that support it.
464 h. New variables to support the bash debugger: BASH_ARGC, BASH_ARGV,
465 BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING,
468 i. FUNCNAME has been changed to support the debugger: it's now an array
471 j. for, case, select, arithmetic commands now keep line number information
474 k. There is a new `RETURN' trap executed when a function or sourced script
475 returns (not inherited child processes; inherited by command substitution
476 if function tracing is enabled and the debugger is active).
478 l. New invocation option: --debugger. Enables debugging and turns on new
479 `extdebug' shell option.
481 m. New `functrace' and `errtrace' options to `set -o' cause DEBUG and ERR
482 traps, respectively, to be inherited by shell functions. Equivalent to
483 `set -T' and `set -E' respectively. The `functrace' option also controls
484 whether or not the DEBUG trap is inherited by sourced scripts.
486 n. The DEBUG trap is run before binding the variable and running the action
487 list in a `for' command, binding the selection variable and running the
488 query in a `select' command, and before attempting a match in a `case'
491 o. New `--enable-debugger' option to `configure' to compile in the debugger
494 p. `declare -F' now prints out extra line number and source file information
495 if the `extdebug' option is set.
497 q. If `extdebug' is enabled, a non-zero return value from a DEBUG trap causes
498 the next command to be skipped, and a return value of 2 while in a
499 function or sourced script forces a `return'.
501 r. New `caller' builtin to provide a call stack for the bash debugger.
503 s. The DEBUG trap is run just before the first command in a function body is
504 executed, for the debugger.
506 t. `for', `select', and `case' command heads are printed when `set -x' is
509 u. There is a new {x..y} brace expansion, which is shorthand for {x.x+1,
510 x+2,...,y}. x and y can be integers or single characters; the sequence
511 may ascend or descend; the increment is always 1.
513 v. New ksh93-like ${!array[@]} expansion, expands to all the keys (indices)
516 w. New `force_fignore' shopt option; if enabled, suffixes specified by
517 FIGNORE cause words to be ignored when performing word completion even
518 if they're the only possibilities.
520 x. New `gnu_errfmt' shopt option; if enabled, error messages follow the `gnu
521 style' (filename:lineno:message) format.
523 y. New `-o bashdefault' option to complete and compgen; if set, causes the
524 whole set of bash completions to be performed if the compspec doesn't
527 z. New `-o plusdirs' option to complete and compgen; if set, causes directory
528 name completion to be performed and the results added to the rest of the
529 possible completions.
531 aa. `kill' is available as a builtin even when the shell is built without
534 bb. New HISTTIMEFORMAT variable; value is a format string to pass to
535 strftime(3). If set and not null, the `history' builtin prints out
536 timestamp information according to the specified format when displaying
537 history entries. If set, bash tells the history library to write out
538 timestamp information when the history file is written.
540 cc. The [[ ... ]] command has a new binary `=~' operator that performs
541 extended regular expression (egrep-like) matching.
543 dd. `configure' has a new `--enable-cond-regexp' option (enabled by default)
544 to enable the =~ operator and regexp matching in [[ ... ]].
546 ee. Subexpressions matched by the =~ operator are placed in the new
547 BASH_REMATCH array variable.
549 ff. New `failglob' option that causes an expansion error when pathname
550 expansion fails to produce a match.
552 gg. New `set -o pipefail' option that causes a pipeline to return a failure
553 status if any of the processes in the pipeline fail, not just the last
556 hh. printf builtin understands two new escape sequences: \" and \?.
558 ii. `echo -e' understands two new escape sequences: \" and \?.
560 jj. The GNU `gettext' package and libintl have been integrated; the shell's
561 messages can be translated into different languages.
563 kk. The `\W' prompt expansion now abbreviates $HOME as `~', like `\w'.
565 ll. The error message printed when bash cannot open a shell script supplied
566 as argument 1 now includes the name of the shell, to better identify
567 the error as coming from bash.
569 mm. The parameter pattern removal and substitution expansions are now much
570 faster and more efficient when using multibyte characters.
572 nn. The `jobs', `kill', and `wait' builtins now accept job control notation
573 even if job control is not enabled.
575 oo. The historical behavior of `trap' that allows a missing `action' argument
576 to cause each specified signal's handling to be reset to its default is
577 now only supported when `trap' is given a single non-option argument.
579 2. New Features in Readline
581 a. History expansion has a new `a' modifier equivalent to the `g' modifier
582 for compatibility with the BSD csh.
584 b. History expansion has a new `G' modifier equivalent to the BSD csh `g'
585 modifier, which performs a substitution once per word.
587 c. All non-incremental search operations may now undo the operation of
588 replacing the current line with the history line.
590 d. The text inserted by an `a' command in vi mode can be reinserted with
593 e. New bindable variable, `show-all-if-unmodified'. If set, the readline
594 completer will list possible completions immediately if there is more
595 than one completion and partial completion cannot be performed.
597 f. There is a new application-callable `free_history_entry()' function.
599 g. History list entries now contain timestamp information; the history file
600 functions know how to read and write timestamp information associated
603 h. Four new key binding functions have been added:
605 rl_bind_key_if_unbound()
606 rl_bind_key_if_unbound_in_map()
607 rl_bind_keyseq_if_unbound()
608 rl_bind_keyseq_if_unbound_in_map()
610 i. New application variable, rl_completion_quote_character, set to any
611 quote character readline finds before it calls the application completion
614 j. New application variable, rl_completion_suppress_quote, settable by an
615 application completion function. If set to non-zero, readline does not
616 attempt to append a closing quote to a completed word.
618 k. New application variable, rl_completion_found_quote, set to a non-zero
619 value if readline determines that the word to be completed is quoted.
620 Set before readline calls any application completion function.
622 l. New function hook, rl_completion_word_break_hook, called when readline
623 needs to break a line into words when completion is attempted. Allows
624 the word break characters to vary based on position in the line.
626 m. New bindable command: unix-filename-rubout. Does the same thing as
627 unix-word-rubout, but adds `/' to the set of word delimiters.
629 n. When listing completions, directories have a `/' appended if the
630 `mark-directories' option has been enabled.
632 -------------------------------------------------------------------------------
633 This is a terse description of the new features added to bash-2.05b since
634 the release of bash-2.05a. As always, the manual page (doc/bash.1) is
635 the place to look for complete descriptions.
637 1. New Features in Bash
639 a. If set, TMOUT is the default timeout for the `read' builtin.
641 b. `type' has two new options: `-f' suppresses shell function lookup, and
642 `-P' forces a $PATH search.
644 c. New code to handle multibyte characters.
646 d. `select' was changed to be more ksh-compatible, in that the menu is
647 reprinted each time through the loop only if REPLY is set to NULL.
648 The previous behavior is available as a compile-time option.
650 e. `complete -d' and `complete -o dirnames' now force a slash to be
651 appended to names which are symlinks to directories.
653 f. There is now a bindable edit-and-execute-command readline command,
654 like the vi-mode `v' command, bound to C-xC-e in emacs mode.
656 g. Added support for ksh93-like [:word:] character class in pattern matching.
658 h. The $'...' quoting construct now expands \cX to Control-X.
660 i. A new \D{...} prompt expansion; passes the `...' to strftime and inserts
661 the result into the expanded prompt.
663 j. The shell now performs arithmetic in the largest integer size the
664 machine supports (intmax_t), instead of long.
666 k. If a numeric argument is supplied to one of the bash globbing completion
667 functions, a `*' is appended to the word before expansion is attempted.
669 l. The bash globbing completion functions now allow completions to be listed
670 with double tabs or if `show-all-if-ambiguous' is set.
672 m. New `-o nospace' option for `complete' and `compgen' builtins; suppresses
673 readline's appending a space to the completed word.
675 n. New `here-string' redirection operator: <<< word.
677 o. When displaying variables, function attributes and definitions are shown
678 separately, allowing them to be re-used as input (attempting to re-use
679 the old output would result in syntax errors).
681 p. There is a new configuration option `--enable-mem-scramble', controls
682 bash malloc behavior of writing garbage characters into memory at
683 allocation and free time.
685 q. The `complete' and `compgen' builtins now have a new `-s/-A service'
686 option to complete on names from /etc/services.
688 r. `read' has a new `-u fd' option to read from a specified file descriptor.
690 s. Fix the completion code so that expansion errors in a directory name
691 don't cause a longjmp back to the command loop.
693 t. Fixed word completion inside command substitution to work a little more
696 u. The `printf' %q format specifier now uses $'...' quoting to print the
697 argument if it contains non-printing characters.
699 v. The `declare' and `typeset' builtins have a new `-t' option. When applied
700 to functions, it causes the DEBUG trap to be inherited by the named
701 function. Currently has no effect on variables.
703 w. The DEBUG trap is now run *before* simple commands, ((...)) commands,
704 [[...]] conditional commands, and for ((...)) loops.
706 x. The expansion of $LINENO inside a shell function is only relative to the
707 function start if the shell is interactive -- if the shell is running a
708 script, $LINENO expands to the line number in the script. This is as
711 y. The bash debugger in examples/bashdb has been modified to work with the
712 new DEBUG trap semantics, the command set has been made more gdb-like,
713 and the changes to $LINENO make debugging functions work better. Code
716 z. New [n]<&word- and [n]>&word- redirections from ksh93 -- move fds (dup
719 aa. There is a new `-l' invocation option, equivalent to `--login'.
721 bb. The `hash' builtin has a new `-l' option to list contents in a reusable
722 format, and a `-d' option to remove a name from the hash table.
724 cc. There is now support for placing the long help text into separate files
725 installed into ${datadir}/bash. Not enabled by default; can be turned
726 on with `--enable-separate-helpfiles' option to configure.
728 dd. All builtins that take operands accept a `--' pseudo-option, except
731 ee. The `echo' builtin now accepts \0xxx (zero to three octal digits following
732 the `0') in addition to \xxx (one to three octal digits) for SUSv3/XPG6/
733 POSIX.1-2001 compliance.
736 2. New Features in Readline
738 a. Support for key `subsequences': allows, e.g., ESC and ESC-a to both
739 be bound to readline functions. Now the arrow keys may be used in vi
742 b. When listing completions, and the number of lines displayed is more than
743 the screen length, readline uses an internal pager to display the results.
744 This is controlled by the `page-completions' variable (default on).
746 c. New code to handle editing and displaying multibyte characters.
748 d. The behavior introduced in bash-2.05a of deciding whether or not to
749 append a slash to a completed name that is a symlink to a directory has
750 been made optional, controlled by the `mark-symlinked-directories'
751 variable (default is the 2.05a behavior).
753 e. The `insert-comment' command now acts as a toggle if given a numeric
754 argument: if the first characters on the line don't specify a
755 comment, insert one; if they do, delete the comment text
757 f. New application-settable completion variable:
758 rl_completion_mark_symlink_dirs, allows an application's completion
759 function to temporarily override the user's preference for appending
760 slashes to names which are symlinks to directories.
762 g. New function available to application completion functions:
763 rl_completion_mode, to tell how the completion function was invoked
764 and decide which argument to supply to rl_complete_internal (to list
767 h. Readline now has an overwrite mode, toggled by the `overwrite-mode'
768 bindable command, which could be bound to `Insert'.
770 i. New application-settable completion variable:
771 rl_completion_suppress_append, inhibits appending of
772 rl_completion_append_character to completed words.
774 j. New key bindings when reading an incremental search string: ^W yanks
775 the currently-matched word out of the current line into the search
776 string; ^Y yanks the rest of the current line into the search string,
777 DEL or ^H deletes characters from the search string.
779 -------------------------------------------------------------------------------
780 This is a terse description of the new features added to bash-2.05a since
781 the release of bash-2.05. As always, the manual page (doc/bash.1) is
782 the place to look for complete descriptions.
784 1. New Features in Bash
786 a. Added support for DESTDIR installation root prefix, so you can do a
787 `make install DESTDIR=bash-root' and do easier binary packaging.
789 b. Added support for builtin printf "'" flag character as per latest POSIX
792 c. Support for POSIX.2 printf(1) length specifiers `j', `t', and `z' (from
795 d. New autoconf macro, RL_LIB_READLINE_VERSION, for use by other applications
796 (bash doesn't use very much of what it returns).
798 e. `set [-+]o nolog' is recognized as required by the latest POSIX drafts,
801 f. New read-only `shopt' option: login_shell. Set to non-zero value if the
802 shell is a login shell.
804 g. New `\A' prompt string escape sequence; expands to time in 24 HH:MM format.
806 h. New `-A group/-g' option to complete and compgen; does group name
809 i. New `-t' option to `hash' to list hash values for each filename argument.
811 j. New [-+]O invocation option to set and unset `shopt' options at startup.
813 k. configure's `--with-installed-readline' option now takes an optional
814 `=PATH' suffix to set the root of the tree where readline is installed
817 l. The ksh-like `ERR' trap has been added. The `ERR' trap will be run
818 whenever the shell would have exited if the -e option were enabled.
819 It is not inherited by shell functions.
821 m. `readonly', `export', and `declare' now print variables which have been
822 given attributes but not set by assigning a value as just a command and
823 a variable name (like `export foo') when listing, as the latest POSIX
826 n. `bashbug' now requires that the subject be changed from the default.
828 o. configure has a new `--enable-largefile' option, like other GNU utilities.
830 p. `for' loops now allow empty word lists after `in', like the latest POSIX
833 q. The builtin `ulimit' now takes two new non-numeric arguments: `hard',
834 meaning the current hard limit, and `soft', meaning the current soft
835 limit, in addition to `unlimited'
837 r. `ulimit' now prints the option letter associated with a particular
838 resource when printing more than one limit.
840 s. `ulimit' prints `hard' or `soft' when a value is not `unlimited' but is
841 one of RLIM_SAVED_MAX or RLIM_SAVED_CUR, respectively.
843 t. The `printf' builtin now handles the %a and %A conversions if they're
844 implemented by printf(3).
846 u. The `printf' builtin now handles the %F conversion (just about like %f).
848 v. The `printf' builtin now handles the %n conversion like printf(3). The
849 corresponding argument is the name of a shell variable to which the
852 2. New Features in Readline
854 a. Added extern declaration for rl_get_termcap to readline.h, making it a
855 public function (it was always there, just not in readline.h).
857 b. New #defines in readline.h: RL_READLINE_VERSION, currently 0x0402,
858 RL_VERSION_MAJOR, currently 4, and RL_VERSION_MINOR, currently 2.
860 c. New readline variable: rl_readline_version, mirrors RL_READLINE_VERSION.
862 d. New bindable boolean readline variable: match-hidden-files. Controls
863 completion of files beginning with a `.' (on Unix). Enabled by default.
865 e. The history expansion code now allows any character to terminate a
866 `:first-' modifier, like csh.
868 f. New bindable variable `history-preserve-point'. If set, the history
869 code attempts to place the user at the same location on each history
870 line retrived with previous-history or next-history.
872 -------------------------------------------------------------------------------
873 This is a terse description of the new features added to bash-2.05 since
874 the release of bash-2.04. As always, the manual page (doc/bash.1) is
875 the place to look for complete descriptions.
877 1. New Features in Bash
879 a. Added a new `--init-file' invocation argument as a synonym for `--rcfile',
880 per the new GNU coding standards.
882 b. The /dev/tcp and /dev/udp redirections now accept service names as well as
885 c. `complete' and `compgen' now take a `-o value' option, which controls some
886 of the aspects of that compspec. Valid values are:
888 default - perform bash default completion if programmable
889 completion produces no matches
890 dirnames - perform directory name completion if programmable
891 completion produces no matches
892 filenames - tell readline that the compspec produces filenames,
893 so it can do things like append slashes to
894 directory names and suppress trailing spaces
896 d. A new loadable builtin, realpath, which canonicalizes and expands symlinks
897 in pathname arguments.
899 e. When `set' is called without options, it prints function defintions in a
900 way that allows them to be reused as input. This affects `declare' and
901 `declare -p' as well. This only happens when the shell is not in POSIX
902 mode, since POSIX.2 forbids this behavior.
904 f. Bash-2.05 once again honors the current locale setting when processing
905 ranges within pattern matching bracket expressions (e.g., [A-Z]).
907 2. New Features in Readline
909 a. The blink timeout for paren matching is now settable by applications,
910 via the rl_set_paren_blink_timeout() function.
912 b. _rl_executing_macro has been renamed to rl_executing_macro, which means
913 it's now part of the public interface.
915 c. Readline has a new variable, rl_readline_state, which is a bitmap that
916 encapsulates the current state of the library; intended for use by
917 callbacks and hook functions.
919 d. New application-callable function rl_set_prompt(const char *prompt):
920 expands its prompt string argument and sets rl_prompt to the result.
922 e. New application-callable function rl_set_screen_size(int rows, int cols):
923 public method for applications to set readline's idea of the screen
926 f. New function, rl_get_screen_size (int *rows, int *columns), returns
927 readline's idea of the screen dimensions.
929 g. The timeout in rl_gather_tyi (readline keyboard input polling function)
930 is now settable via a function (rl_set_keyboard_input_timeout()).
932 h. Renamed the max_input_history variable to history_max_entries; the old
933 variable is maintained for backwards compatibility.
935 i. The list of characters that separate words for the history tokenizer is
936 now settable with a variable: history_word_delimiters. The default
939 -------------------------------------------------------------------------------
940 This is a terse description of the new features added to bash-2.04 since
941 the release of bash-2.03. As always, the manual page (doc/bash.1) is
942 the place to look for complete descriptions.
944 1. New Features in Bash
946 a. The history builtin has a `-d offset' option to delete the history entry
947 at position `offset'.
949 b. The prompt expansion code has two new escape sequences: \j, the number of
950 active jobs; and \l, the basename of the shell's tty device name.
952 c. The `bind' builtin has a new `-x' option to bind key sequences to shell
955 d. There is a new shell option, no_empty_command_completion, which, when
956 enabled, disables command completion when TAB is typed on an empty line.
958 e. The `help' builtin has a `-s' option to just print a builtin's usage
961 f. There are several new arithmetic operators: id++, id-- (variable
962 post-increment/decrement), ++id, --id (variable pre-increment/decrement),
963 expr1 , expr2 (comma operator).
965 g. There is a new ksh-93 style arithmetic for command:
966 for ((expr1 ; expr2; expr3 )); do list; done
968 h. The `read' builtin has a number of new options:
969 -t timeout only wait timeout seconds for input
970 -n nchars only read nchars from input instead of a full line
971 -d delim read until delim rather than newline
972 -s don't echo input chars as they are read
974 i. The redirection code now handles several filenames specially:
975 /dev/fd/N, /dev/stdin, /dev/stdout, and /dev/stderr, whether or
976 not they are present in the file system.
978 j. The redirection code now recognizes pathnames of the form
979 /dev/tcp/host/port and /dev/udp/host/port, and tries to open a socket
980 of the appropriate type to the specified port on the specified host.
982 k. The ksh-93 ${!prefix*} expansion, which expands to the names of all
983 shell variables with prefix PREFIX, has been implemented.
985 l. There is a new dynamic variable, FUNCNAME, which expands to the name of
986 a currently-executing function. Assignments to FUNCNAME have no effect.
988 m. The GROUPS variable is no longer readonly; assignments to it are silently
989 discarded. This means it can be unset.
991 n. A new programmable completion facility, with two new builtin commands:
992 complete and compgen.
994 o. configure has a new option, `--enable-progcomp', to compile in the
995 programmable completion features (enabled by default).
997 p. `shopt' has a new option, `progcomp', to enable and disable programmable
998 completion at runtime.
1000 q. Unsetting HOSTFILE now clears the list of hostnames used for completion.
1002 r. configure has a new option, `--enable-bash-malloc', replacing the old
1003 `--with-gnu-malloc' (which is still present for backwards compatibility).
1005 s. There is a new manual page describing rbash, the restricted shell.
1007 t. `bashbug' has new `--help' and `--version' options.
1009 u. `shopt' has a new `xpg_echo' option, which controls the behavior of
1010 `echo' with respect to backslash-escaped characters at runtime.
1012 v. If NON_INTERACTIVE_LOGIN_SHELLS is defined, all login shells read the
1013 startup files, even if they are not interactive.
1015 w. The LC_NUMERIC variable is now treated specially, and used to set the
1016 LC_NUMERIC locale category for number formatting, e.g., when `printf'
1017 displays floating-point numbers.
1019 2. New features in Readline
1021 a. Parentheses matching is now always compiled into readline, and enabled
1022 or disabled when the value of the `blink-matching-paren' variable is
1025 b. MS-DOS systems now use ~/_inputrc as the last-ditch inputrc filename.
1027 c. MS-DOS systems now use ~/_history as the default history file.
1029 d. history-search-{forward,backward} now leave the point at the end of the
1030 line when the string to search for is empty, like
1031 {reverse,forward}-search-history.
1033 e. history-search-{forward,backward} now leave the last history line found
1034 in the readline buffer if the second or subsequent search fails.
1036 f. New function for use by applications: rl_on_new_line_with_prompt, used
1037 when an application displays the prompt itself before calling readline().
1039 g. New variable for use by applications: rl_already_prompted. An application
1040 that displays the prompt itself before calling readline() must set this to
1043 h. A new variable, rl_gnu_readline_p, always 1. The intent is that an
1044 application can verify whether or not it is linked with the `real'
1045 readline library or some substitute.
1047 -------------------------------------------------------------------------------
1048 This is a terse description of the new features added to bash-2.03 since
1049 the release of bash-2.02. As always, the manual page (doc/bash.1) is
1050 the place to look for complete descriptions.
1052 1. New Features in Bash
1054 a. New `shopt' option, `restricted_shell', indicating whether or not the
1055 shell was started in restricted mode, for use in startup files.
1057 b. Filename generation is now performed on the words between ( and ) in
1058 array assignments (which it probably should have done all along).
1060 c. OLDPWD is now auto-exported, as POSIX.2 seems to require.
1062 d. ENV and BASH_ENV are read-only variables in a restricted shell.
1064 e. A change was made to the startup file code so that any shell begun with
1065 the `--login' option, even non-interactive shells, will source the login
1066 shell startup files.
1068 2. New Features in Readline
1070 a. Many changes to the signal handling:
1071 o Readline now catches SIGQUIT and cleans up the tty before returning;
1072 o A new variable, rl_catch_signals, is available to application writers
1073 to indicate to readline whether or not it should install its own
1074 signal handlers for SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP,
1075 SIGTTIN, and SIGTTOU;
1076 o A new variable, rl_catch_sigwinch, is available to application
1077 writers to indicate to readline whether or not it should install its
1078 own signal handler for SIGWINCH, which will chain to the calling
1079 applications's SIGWINCH handler, if one is installed;
1080 o There is a new function, rl_free_line_state, for application signal
1081 handlers to call to free up the state associated with the current
1082 line after receiving a signal;
1083 o There is a new function, rl_cleanup_after_signal, to clean up the
1084 display and terminal state after receiving a signal;
1085 o There is a new function, rl_reset_after_signal, to reinitialize the
1086 terminal and display state after an application signal handler
1087 returns and readline continues
1089 b. There is a new function, rl_resize_terminal, to reset readline's idea of
1090 the screen size after a SIGWINCH.
1092 c. New public functions: rl_save_prompt and rl_restore_prompt. These were
1093 previously private functions with a `_' prefix.
1095 d. New function hook: rl_pre_input_hook, called just before readline starts
1096 reading input, after initialization.
1098 e. New function hook: rl_display_matches_hook, called when readline would
1099 display the list of completion matches. The new function
1100 rl_display_match_list is what readline uses internally, and is available
1101 for use by application functions called via this hook.
1103 f. New bindable function, delete-char-or-list, like tcsh.
1105 g. A new variable, rl_erase_empty_line, which, if set by an application using
1106 readline, will cause readline to erase, prompt and all, lines on which the
1107 only thing typed was a newline.
1109 h. New bindable variable: `isearch-terminators'.
1111 i. New bindable function: `forward-backward-delete-char' (unbound by default).
1113 -------------------------------------------------------------------------------
1114 This is a terse description of the new features added to bash-2.02 since
1115 the release of bash-2.01.1. As always, the manual page (doc/bash.1) is
1116 the place to look for complete descriptions.
1118 1. New Features in Bash
1120 a. A new version of malloc, based on the older GNU malloc, that has many
1121 changes, is more page-based, is more conservative with memory usage,
1122 and does not `orphan' large blocks when they are freed.
1124 b. A new version of gmalloc, based on the old GLIBC malloc, with many
1125 changes and range checking included by default.
1127 c. A new implementation of fnmatch(3) that includes full POSIX.2 Basic
1128 Regular Expression matching, including character classes, collating
1129 symbols, equivalence classes, and support for case-insensitive pattern
1132 d. ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been
1133 implemented, controlled by a new `shopt' option, `extglob'.
1135 e. There is a new ksh-like `[[' compound command, which implements
1136 extended `test' functionality.
1138 f. There is a new `printf' builtin, implemented according to the POSIX.2
1141 g. There is a new feature for command substitution: $(< filename) now expands
1142 to the contents of `filename', with any trailing newlines removed
1143 (equivalent to $(cat filename)).
1145 h. There are new tilde prefixes which expand to directories from the
1148 i. There is a new `**' arithmetic operator to do exponentiation.
1150 j. There are new configuration options to control how bash is linked:
1151 `--enable-profiling', to allow bash to be profiled with gprof, and
1152 `--enable-static-link', to allow bash to be linked statically.
1154 k. There is a new configuration option, `--enable-cond-command', which
1155 controls whether or not the `[[' command is included. It is on by
1158 l. There is a new configuration option, `--enable-extended-glob', which
1159 controls whether or not the ksh extended globbing feature is included.
1160 It is enabled by default.
1162 m. There is a new configuration #define in config.h.top that, when enabled,
1163 will cause all login shells to source /etc/profile and one of the user-
1164 specific login shell startup files, whether or not the shell is
1167 n. There is a new invocation option, `--dump-po-strings', to dump
1168 a shell script's translatable strings ($"...") in GNU `po' format.
1170 o. There is a new `shopt' option, `nocaseglob', to enable case-insensitive
1171 pattern matching when globbing filenames and using the `case' construct.
1173 p. There is a new `shopt' option, `huponexit', which, when enabled, causes
1174 the shell to send SIGHUP to all jobs when an interactive login shell
1177 q. `bind' has a new `-u' option, which takes a readline function name as an
1178 argument and unbinds all key sequences bound to that function in a
1181 r. `disown' now has `-a' and `-r' options, to limit operation to all jobs
1182 and running jobs, respectively.
1184 s. The `shopt' `-p' option now causes output to be displayed in a reusable
1187 t. `test' has a new `-N' option, which returns true if the filename argument
1188 has been modified since it was last accessed.
1190 u. `umask' now has a `-p' option to print output in a reusable format.
1192 v. A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...'
1193 translation code. It expands to the character whose ascii code is NNN
1196 w. The prompt string expansion code has a new `\r' escape sequence.
1198 x. The shell may now be cross-compiled for the CYGWIN32 environment on
1201 2. New Features in Readline
1203 a. There is now an option for `iterative' yank-last-arg handline, so a user
1204 can keep entering `M-.', yanking the last argument of successive history
1207 b. New variable, `print-completions-horizontally', which causes completion
1208 matches to be displayed across the screen (like `ls -x') rather than up
1209 and down the screen (like `ls').
1211 c. New variable, `completion-ignore-case', which causes filename completion
1212 and matching to be performed case-insensitively.
1214 d. There is a new bindable command, `magic-space', which causes history
1215 expansion to be performed on the current readline buffer and a space to
1216 be inserted into the result.
1218 e. There is a new bindable command, `menu-complete', which enables tcsh-like
1219 menu completion (successive executions of menu-complete insert a single
1220 completion match, cycling through the list of possible completions).
1222 f. There is a new bindable command, `paste-from-clipboard', for use on Win32
1223 systems, to insert the text from the Win32 clipboard into the editing
1226 g. The key sequence translation code now understands printf-style backslash
1227 escape sequences, including \NNN octal escapes. These escape sequences
1228 may be used in key sequence definitions or macro values.
1230 h. An `$include' inputrc file parser directive has been added.
1232 -------------------------------------------------------------------------------
1233 This is a terse description of the new features added to bash-2.01 since
1234 the release of bash-2.0. As always, the manual page (doc/bash.1) is the
1235 place to look for complete descriptions.
1237 1. New Features in Bash
1239 a. There is a new builtin array variable: GROUPS, the set of groups to which
1240 the user belongs. This is used by the test suite.
1242 2. New Features in Readline
1244 a. If a key sequence bound to `universal-argument' is read while reading a
1245 numeric argument started with `universal-argument', it terminates the
1246 argument but is otherwise ignored. This provides a way to insert multiple
1247 instances of a digit string, and is how GNU emacs does it.
1249 -------------------------------------------------------------------------------
1250 This is a terse description of the new features added to bash-2.0 since
1251 the release of bash-1.14.7. As always, the manual page (doc/bash.1) is
1252 the place to look for complete descriptions.
1254 1. New Features in Bash
1256 a. There is a new invocation option, -D, that dumps translatable strings
1259 b. The `long' invocation options must now be prefixed with `--'.
1261 c. New long invocation options: --dump-strings, --help, --verbose
1263 d. The `nolineediting' invocation option was renamed to `noediting'.
1265 e. The `nobraceexpansion' and `quiet' long invocation options were removed.
1267 f. The `--help' and `--version' long options now work as the GNU coding
1270 g. If invoked as `sh', bash now enters posix mode after reading the
1271 startup files, and reads and executes commands from the file named
1272 by $ENV if interactive (as POSIX.2 specifies). A login shell invoked
1273 as `sh' reads $ENV after /etc/profile and ~/.profile.
1275 h. There is a new reserved word, `time', for timing pipelines, builtin
1276 commands, and shell functions. It uses the value of the TIMEFORMAT
1277 variable as a format string describing how to print the timing
1280 i. The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the
1281 result single-quoted.
1283 j. The $"..." quoting syntax performs locale-specific translation of ...
1284 and leaves the result double-quoted.
1286 k. LINENO now works correctly in functions.
1288 l. New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS,
1289 MACHTYPE. The first three are array variables.
1291 m. The BASH_VERSION and BASH_VERSINFO variables now include the shell's
1292 `release status' (alpha[N], beta[N], release).
1294 n. Some variables have been removed: MAIL_WARNING, notify, history_control,
1295 command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
1296 nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
1297 cdable_vars. Most of them are now implemented with the new `shopt'
1298 builtin; others were already implemented by `set'.
1300 o. Bash now uses some new variables: LC_ALL, LC_MESSAGES, LC_CTYPE,
1301 LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE.
1303 p. The shell now supports integer-indexed arrays of unlimited length,
1304 with a new compound assignment syntax and changes to the appropriate
1305 builtin commands (declare/typeset, read, readonly, etc.). The array
1306 index may be an arithmetic expression.
1308 q. ${!var}: indirect variable expansion, equivalent to eval \${$var}.
1310 r. ${paramter:offset[:length]}: variable substring extraction.
1312 s. ${parameter/pattern[/[/]string]}: variable pattern substitution.
1314 t. The $[...] arithmetic expansion syntax is no longer supported, in
1317 u. Aliases can now be expanded in shell scripts with a shell option
1318 (shopt expand_aliases).
1320 v. History and history expansion can now be used in scripts with
1321 set -o history and set -H.
1323 w. All builtins now return an exit status of 2 for incorrect usage.
1325 x. Interactive shells resend SIGHUP to all running or stopped children
1326 if (and only if) they exit due to a SIGHUP.
1328 y. New prompting expansions: \a, \e, \H, \T, \@, \v, \V.
1330 z. Variable expansion in prompt strings is now controllable via a shell
1331 option (shopt promptvars).
1333 aa. Bash now defaults to using command-oriented history.
1335 bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after
1338 cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr)
1339 has been implemented.
1341 dd. Each builtin now accepts `--' to signify the end of the options, except
1342 as documented (echo, etc.).
1344 ee. All builtins use -p to display values in a re-readable format where
1345 appropriate, except as documented (echo, type, etc.).
1347 ff. The `alias' builtin has a new -p option.
1349 gg. Changes to the `bind' builtin:
1350 o has new options: -psPSVr.
1351 o the `-d' option was renamed to `-p'
1352 o the `-v' option now dumps variables; the old `-v' is now `-P'
1354 hh. The `bye' synonym for `exit' was removed.
1356 ii. The -L and -P options to `cd' and `pwd' have been documented.
1358 jj. The `cd' builtin now does spelling correction on the directory name
1359 by default. This is settable with a shell option (shopt cdspell).
1361 kk. The `declare' builtin has new options: -a, -F, -p.
1363 ll. The `dirs' builtin has new options: -c, -p, -v.
1365 mm. The new `disown' builtin removes jobs from the shell's jobs table
1366 or inhibits the resending of SIGHUP when the shell receives a
1369 nn. The `echo' builtin has a new escape character: \e.
1371 oo. The `enable' builtin can now load new builtins dynamically from shared
1372 objects on systems with the dlopen/dlsym interface. There are a number
1373 of examples in the examples/loadables directory. There are also
1374 new options: -d, -f, -s, -p.
1376 pp. The `-all' option to `enable' was removed in favor of `-a'.
1378 qq. The `exec' builtin has new options: -l, -c, -a.
1380 rr. The `hash' builtin has a new option: -p.
1382 ss. The `history' builtin has new options: -c, -p, -s.
1384 tt. The `jobs' builtin has new options: -r, -s.
1386 uu. The `kill' builtin has new options: -n signum, -l signame.
1388 vv. The `pushd' and `popd' builtins have a new option: -n.
1390 ww. The `read' builtin has new options: -p prompt, -e, -a.
1392 xx. The `readonly' builtin has a new -a option, and the -n option was removed.
1394 yy. Changes to the `set' builtin:
1395 o new options: -B, -o keyword, -o onecmd, -o history
1396 o options removed: -l, -d, -o nohash
1397 o options changed: +o, -h, -o hashall
1398 o now displays variables in a format that can be re-read as input
1400 zz. The new `shopt' builtin controls shell optional behavior previously
1401 done by setting and unsetting certain shell variables.
1403 aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2,
1404 and s1 > s2, where s1 and s2 are strings.
1406 bbb. There is a new trap, DEBUG, executed after every simple command.
1408 ccc. The `trap' builtin has a new -p option.
1410 ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems.
1412 eee. The PS1, PS2, PATH, and IFS variables may now be unset.
1414 fff. The restricted shell mode has been expanded and is now documented.
1416 ggg. Security improvements:
1417 o functions are not imported from the environment if running setuid
1419 o no startup files are sourced if running setuid or with -p
1421 hhh. The documentation has been overhauled: the texinfo manual was
1422 expanded, and HTML versions of the man page and texinfo manual
1425 iii. Changes to Posix mode:
1426 o Command lookup now finds special builtins before shell functions.
1427 o Failure of a special builtin causes a non-interactive shell to
1428 exit. Failures are defined in the POSIX.2 specification.
1429 o If the `cd' builtin finds a directory to change to using $CDPATH,
1430 the value assigned to PWD when `cd' completes does not contain
1432 o A non-interactive shell exits if a variable assignment error
1433 occurs when no command name follows the assignment statements.
1434 o A non-interactive shell exits if the interation variable in a
1435 `for' statement or the selection variable in a `select' statement
1436 is read-only or another variable assignment error occurs.
1437 o The `<>' redirection operator now opens a file for both stdin and
1438 stdout by default, not just when in posix mode.
1439 o Assignment statements preceding special builtins now persist in
1440 the shell's environment when the builtin completes.
1442 Posix mode is now completely POSIX.2-compliant (modulo bugs). When
1443 invoked as sh, bash should be completely POSIX.2-compliant.
1445 jjj. The default value of PS1 is now "\s-\v\$ ".
1447 kkk. The ksh-like ((...)) arithmetic command syntax has been implemented.
1448 This is exactly equivalent to `let "..."'.
1450 lll. Integer constants have been extended to base 64.
1452 mmm. The `ulimit' builtin now sets both hard and soft limits and reports the
1453 soft limit by default.
1455 2. New Features in Readline
1457 a. New variables: enable-keypad, input-meta (new name for meta-flag),
1458 mark-directories, visible-stats (now documented), disable-completion,
1461 b. New bindable commands: kill-region, copy-region-as-kill,
1462 copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark,
1463 character-search, character-search-backward, insert-comment,
1464 glob-expand-word, glob-list-expansions, dump-variables, dump-macros.
1466 c. New emacs keybindings: delete-horizontal-space (M-\),
1467 insert-completions (M-*), possible-completions (M-=).
1469 d. The history-search-backward and history-search-forward commands were
1470 modified to be the same as previous-line and next-line if point is at
1471 the start of the line.
1473 e. More file types are available for the visible-stats mode.
1475 3. Changes of interest in the Bash implementation
1477 a. There is a new autoconf-based configuration mechanism.
1479 b. More things have been moved from Posix mode to standard shell behavior.
1481 c. The trace output (set -x) now inserts quotes where necessary so it can
1484 d. There is a compile-time option for a system-wide interactive shell
1485 startup file (disabled by default).
1487 e. The YACC grammar is smaller and tighter, and all 66 shift-reduce
1488 conflicts are gone. Several parsing bugs have been fixed.
1490 f. Builtin option parsing has been regularized (using internal_getopt()),
1491 with the exception of `echo', `type', and `set'.
1493 g. Builtins now return standard usage messages constructed from the
1494 `short doc' used by the help builtin.
1496 h. Completion now quotes using backslashes by default, but honors
1497 user-supplied quotes.
1499 i. The GNU libc malloc is available as a configure-time option.
1501 j. There are more internationalization features; bash uses gettext if
1502 it is available. The $"..." translation syntax uses the current
1505 k. There is better reporting of job termination when the shell is not
1508 l. The shell is somewhat more efficient: it uses a little less memory and
1509 makes fewer system calls.
1511 4. Changes of interest in the Readline implementation
1513 a. There is now support for readline `callback' functions.
1515 b. There is now support for user-supplied input, redisplay, and terminal
1516 preparation functions.
1518 c. Most of the shell-specific code in readline has been generalized or
1521 d. Most of the annoying redisplay bugs have been fixed, notably the problems
1522 with incremental search and excessive redrawing when special characters
1523 appear in the prompt string.
1525 e. There are new library functions and variables available to application
1526 writers, most having to do with completion and quoting.
1528 f. The NEWLINE character (^J) is now treated as a search terminator by the
1529 incremental search functions.
1530 -------------------------------------------------------------------------------
1532 Copying and distribution of this file, with or without modification,
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1534 notice and this notice are preserved. This file is offered as-is,
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