1 This is a terse description of the new features added to bash-5.0 since
2 the release of bash-4.4. 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. The `wait' builtin can now wait for the last process substitution created.
9 b. There is an EPOCHSECONDS variable, which expands to the time in seconds
12 c. There is an EPOCHREALTIME variable, which expands to the time in seconds
13 since the Unix epoch with microsecond granularity.
15 d. New loadable builtins: rm, stat, fdflags.
17 e. BASH_ARGV0: a new variable that expands to $0 and sets $0 on assignment.
19 f. When supplied a numeric argument, the shell-expand-line bindable readline
20 command does not perform quote removal and suppresses command and process
23 g. `history -d' understands negative arguments: negative arguments offset from
24 the end of the history list.
26 h. The `name' argument to the `coproc' reserved word now undergoes word
27 expansion, so unique coprocs can be created in loops.
29 i. A nameref name resolution loop in a function now resolves to a variable by
30 that name in the global scope.
32 j. The `wait' builtin now has a `-f' option, which signfies to wait until the
33 specified job or process terminates, instead of waiting until it changes
36 k. There is a define in config-top.h that allows the shell to use a static
37 value for $PATH, overriding whatever is in the environment at startup, for
38 use by the restricted shell.
40 l. Process substitution does not inherit the `v' option, like command
43 m. If a non-interactive shell with job control enabled detects that a foreground
44 job died due to SIGINT, it acts as if it received the SIGINT.
46 n. The SIGCHLD trap is run once for each exiting child process even if job
47 control is not enabled when the shell is in Posix mode.
49 o. A new shopt option: localvar_inherit; if set, a local variable inherits the
50 value of a variable with the same name at the nearest preceding scope.
52 p. `bind -r' now checks whether a key sequence is bound before binding it to
53 NULL, to avoid creating keymaps for a multi-key sequence.
55 q. A numeric argument to the line editing `operate-and-get-next' command
56 specifies which history entry to use.
58 r. The positional parameters are now assigned before running the shell startup
59 files, so startup files can use $@.
61 s. There is a compile-time option that forces the shell to disable the check
62 for an inherited OLDPWD being a directory.
64 t. The `history' builtin can now delete ranges of history entries using
67 u. The `vi-edit-and-execute-command' bindable readline command now puts readline
68 back in vi insertion mode after executing commands from the edited file.
70 v. The command completion code now matches aliases and shell function names
71 case-insensitively if the readline completion-ignore-case variable is set.
73 w. There is a new `assoc_expand_once' shell option that attempts to expand
74 associative array subscripts only once.
76 x. The shell only sets up BASH_ARGV and BASH_ARGC at startup if extended
77 debugging mode is active. The old behavior of unconditionally setting them
78 is available as part of the shell compatibility options.
80 y. The `umask' builtin now allows modes and masks greater than octal 777.
82 z. The `times' builtin now honors the current locale when printing a decimal
85 aa. There is a new (disabled by default, undocumented) shell option to enable
86 and disable sending history to syslog at runtime.
88 bb. Bash no longer allows variable assignments preceding a special builtin that
89 changes variable attributes to propagate back to the calling environment
90 unless the compatibility level is 44 or lower.
92 cc. You can set the default value for $HISTSIZE at build time in config-top.h.
94 dd. The `complete' builtin now accepts a -I option that applies the completion
95 to the initial word on the line.
97 ee. The internal bash malloc now uses mmap (if available) to satisfy requests
98 greater than 128K bytes, so free can use mfree to return the pages to the
101 ff. The shell doesn't automatically set BASH_ARGC and BASH_ARGV at startup
102 unless it's in debugging mode, as the documentation has always said, but
103 will dynamically create them if a script references them at the top level
104 without having enabled debugging mode.
106 gg. The localvar_inherit option will not attempt to inherit a value from a
107 variable of an incompatible type (indexed vs. associative arrays, for
110 hh. The `globasciiranges' option is now enabled by default; it can be set to
111 off by default at configuration time.
113 ii. Associative and indexed arrays now allow subscripts consisting solely of
116 jj. `checkwinsize' is now enabled by default.
118 kk. The `localvar_unset' shopt option is now visible and documented.
120 ll. The `progcomp_alias' shopt option is now visible and documented.
122 mm. The signal name processing code now understands `SIGRTMIN+n' all the way
125 nn. There is a new `seq' loadable builtin.
127 oo. Trap execution now honors the (internal) max invocations of `eval', since
128 traps are supposed to be executed as if using `eval'.
130 pp. The $_ variable doesn't change when the shell executes a command that forks.
132 qq. The `kill' builtin now supports -sSIGNAME and -nSIGNUM, even though
133 conforming applications aren't supposed to use them.
135 rr. POSIX mode now enables the `shift_verbose' option.
137 2. New Features in Readline
139 a. Non-incremental vi-mode search (`N', `n') can search for a shell pattern, as
140 Posix specifies (uses fnmatch(3) if available).
142 b. There are new `next-screen-line' and `previous-screen-line' bindable
143 commands, which move the cursor to the same column in the next, or previous,
144 physical line, respectively.
146 c. There are default key bindings for control-arrow-key key combinations.
148 d. A negative argument (-N) to `quoted-insert' means to insert the next N
149 characters using quoted-insert.
151 e. New public function: rl_check_signals(), which allows applications to
152 respond to signals that readline catches while waiting for input using
153 a custom read function.
155 f. There is new support for conditionally testing the readline version in an
156 inputrc file, with a full set of arithmetic comparison operators available.
158 g. There is a simple variable comparison facility available for use within an
159 inputrc file. Allowable operators are equality and inequality; string
160 variables may be compared to a value; boolean variables must be compared to
161 either `on' or `off'; variable names are separated from the operator by
164 h. The history expansion library now understands command and process
165 substitution and extended globbing and allows them to appear anywhere in a
168 i. The history library has a new variable that allows applications to set the
169 initial quoting state, so quoting state can be inherited from a previous
172 j. Readline now allows application-defined keymap names; there is a new public
173 function, rl_set_keymap_name(), to do that.
175 k. The "Insert" keypad key, if available, now puts readline into overwrite
178 -------------------------------------------------------------------------------
179 This is a terse description of the new features added to bash-4.4 since
180 the release of bash-4.3. As always, the manual page (doc/bash.1) is
181 the place to look for complete descriptions.
183 1. New Features in Bash
185 a. There is now a settable configuration #define that will cause the shell
186 to exit if the shell is running setuid without the -p option and setuid
187 to the real uid fails.
189 b. Command and process substitutions now turn off the `-v' option when
190 executing, as other shells seem to do.
192 c. The default value for the `checkhash' shell option may now be set at
193 compile time with a #define.
195 d. The `mapfile' builtin now has a -d option to use an arbitrary character
196 as the record delimiter, and a -t option to strip the delimiter as
199 e. The maximum number of nested recursive calls to `eval' is now settable in
200 config-top.h; the default is no limit.
202 f. The `-p' option to declare and similar builtins will display attributes for
203 named variables even when those variables have not been assigned values
204 (which are technically unset).
206 g. The maximum number of nested recursive calls to `source' is now settable
207 in config-top.h; the default is no limit.
209 h. All builtin commands recognize the `--help' option and print a usage
212 i. Bash does not allow function names containing `/' and `=' to be exported.
214 j. The `ulimit' builtin has new -k (kqueues) and -P (pseudoterminals) options.
216 k. The shell now allows `time ; othercommand' to time null commands.
218 l. There is a new `--enable-function-import' configuration option to allow
219 importing shell functions from the environment; import is enabled by
222 m. `printf -v var ""' will now set `var' to the empty string, as if `var=""'
225 n. GLOBIGNORE, the pattern substitution word expansion, and programmable
226 completion match filtering now honor the value of the `nocasematch' option.
228 o. There is a new ${parameter@spec} family of operators to transform the
229 value of `parameter'.
231 p. Bash no longer attempts to perform compound assignment if a variable on the
232 rhs of an assignment statement argument to `declare' has the form of a
233 compound assignment (e.g., w='(word)' ; declare foo=$w); compound
234 assignments are accepted if the variable was already declared as an array,
237 q. The declare builtin no longer displays array variables using the compound
238 assignment syntax with quotes; that will generate warnings when re-used as
239 input, and isn't necessary.
241 r. Executing the rhs of && and || will no longer cause the shell to fork if
244 s. The `local' builtin takes a new argument: `-', which will cause it to save
245 and the single-letter shell options and restore their previous values at
248 t. `complete' and `compgen' have a new `-o nosort' option, which forces
249 readline to not sort the completion matches.
251 u. Bash now allows waiting for the most recent process substitution, since it
254 v. The `unset' builtin now unsets a scalar variable if it is subscripted with
255 a `0', analogous to the ${var[0]} expansion.
257 w. `set -i' is no longer valid, as in other shells.
259 x. BASH_SUBSHELL is now updated for process substitution and group commands
260 in pipelines, and is available with the same value when running any exit
263 y. Bash now checks $INSIDE_EMACS as well as $EMACS when deciding whether or
264 not bash is being run in a GNU Emacs shell window.
266 z. Bash now treats SIGINT received when running a non-builtin command in a
267 loop the way it has traditionally treated running a builtin command:
268 running any trap handler and breaking out of the loop.
270 aa. New variable: EXECIGNORE; a colon-separate list of patterns that will
271 cause matching filenames to be ignored when searching for commands.
273 bb. Aliases whose value ends in a shell metacharacter now expand in a way to
274 allow them to be `pasted' to the next token, which can potentially change
275 the meaning of a command (e.g., turning `&' into `&&').
277 cc. `make install' now installs the example loadable builtins and a set of
278 bash headers to use when developing new loadable builtins.
280 dd. `enable -f' now attempts to call functions named BUILTIN_builtin_load when
281 loading BUILTIN, and BUILTIN_builtin_unload when deleting it. This allows
282 loadable builtins to run initialization and cleanup code.
284 ee. There is a new BASH_LOADABLES_PATH variable containing a list of directories
285 where the `enable -f' command looks for shared objects containing loadable
288 ff. The `complete_fullquote' option to `shopt' changes filename completion to
289 quote all shell metacharacters in filenames and directory names.
291 gg. The `kill' builtin now has a `-L' option, equivalent to `-l', for
292 compatibility with Linux standalone versions of kill.
294 hh. BASH_COMPAT and FUNCNEST can be inherited and set from the shell's initial
297 ii. inherit_errexit: a new `shopt' option that, when set, causes command
298 substitutions to inherit the -e option. By default, those subshells disable
299 -e. It's enabled as part of turning on posix mode.
301 jj. New prompt string: PS0. Expanded and displayed by interactive shells after
302 reading a complete command but before executing it.
304 kk. Interactive shells now behave as if SIGTSTP/SIGTTIN/SIGTTOU are set to
305 SIG_DFL when the shell is started, so they are set to SIG_DFL in child
308 ll. Posix-mode shells now allow double quotes to quote the history expansion
311 mm. OLDPWD can be inherited from the environment if it names a directory.
313 nn. Shells running as root no longer inherit PS4 from the environment, closing
314 a security hole involving PS4 expansion performing command substitution.
316 oo. If executing an implicit `cd' when the `autocd' option is set, bash will
317 now invoke a function named `cd' if one exists before executing the `cd'
320 pp. Value conversions (arithmetic expansions, case modification, etc.) now
321 happen when assigning elements of an array using compound assignment.
323 qq. There is a new option settable in config-top.h that makes multiple
324 directory arguments to `cd' a fatal error.
326 rr. Bash now uses mktemp() when creating internal temporary files; it produces
327 a warning at build time on many Linux systems.
329 2. New Features in Readline
331 a. The history truncation code now uses the same error recovery mechansim as
332 the history writing code, and restores the old version of the history file
333 on error. The error recovery mechanism handles symlinked history files.
335 b. There is a new bindable variable, `enable-bracketed-paste', which enables
336 support for a terminal's bracketed paste mode.
338 c. The editing mode indicators can now be strings and are user-settable
339 (new `emacs-mode-string', `vi-cmd-mode-string' and `vi-ins-mode-string'
340 variables). Mode strings can contain invisible character sequences.
341 Setting mode strings to null strings restores the defaults.
343 d. Prompt expansion adds the mode string to the last line of a multi-line
344 prompt (one with embedded newlines).
346 e. There is a new bindable variable, `colored-completion-prefix', which, if
347 set, causes the common prefix of a set of possible completions to be
350 f. There is a new bindable command `vi-yank-pop', a vi-mode version of emacs-
353 g. The redisplay code underwent several efficiency improvements for multibyte
356 h. The insert-char function attempts to batch-insert all pending typeahead
357 that maps to self-insert, as long as it is coming from the terminal.
359 i. rl_callback_sigcleanup: a new application function that can clean up and
360 unset any state set by readline's callback mode. Intended to be used
363 j. If an incremental search string has its last character removed with DEL, the
364 resulting empty search string no longer matches the previous line.
366 k. If readline reads a history file that begins with `#' (or the value of
367 the history comment character) and has enabled history timestamps, the
368 history entries are assumed to be delimited by timestamps. This allows
369 multi-line history entries.
371 l. Readline now throws an error if it parses a key binding without a
372 terminating `:' or whitespace.
374 m. The default binding for ^W in vi mode now uses word boundaries specified
375 by Posix (vi-unix-word-rubout is bindable command name).
377 n. rl_clear_visible_line: new application-callable function; clears all
378 screen lines occupied by the current visible readline line.
380 o. rl_tty_set_echoing: application-callable function that controls whether
381 or not readline thinks it is echoing terminal output.
383 p. Handle >| and strings of digits preceding and following redirection
384 specifications as single tokens when tokenizing the line for history
387 q. Fixed a bug with displaying completions when the prefix display length
388 is greater than the length of the completions to be displayed.
390 r. The :p history modifier now applies to the entire line, so any expansion
391 specifying :p causes the line to be printed instead of expanded.
393 s. New application-callable function: rl_pending_signal(): returns the signal
394 number of any signal readline has caught but not yet handled.
396 t. New application-settable variable: rl_persistent_signal_handlers: if set
397 to a non-zero value, readline will enable the readline-6.2 signal handler
398 behavior in callback mode: handlers are installed when
399 rl_callback_handler_install is called and removed removed when a complete
402 -------------------------------------------------------------------------------
403 This is a terse description of the new features added to bash-4.3 since
404 the release of bash-4.2. As always, the manual page (doc/bash.1) is
405 the place to look for complete descriptions.
407 1. New Features in Bash
409 a. The `helptopic' completion action now maps to all the help topics, not just
412 b. The `help' builtin no longer does prefix substring matching first, so
413 `help read' does not match `readonly', but will do it if exact string
416 c. The shell can be compiled to not display a message about processes that
417 terminate due to SIGTERM.
419 d. Non-interactive shells now react to the setting of checkwinsize and set
420 LINES and COLUMNS after a foreground job exits.
422 e. There is a new shell option, `globasciiranges', which, when set to on,
423 forces globbing range comparisons to use character ordering as if they
424 were run in the C locale.
426 f. There is a new shell option, `direxpand', which makes filename completion
427 expand variables in directory names in the way bash-4.1 did.
429 g. In Posix mode, the `command' builtin does not change whether or not a
430 builtin it shadows is treated as an assignment builtin.
432 h. The `return' and `exit' builtins accept negative exit status arguments.
434 i. The word completion code checks whether or not a filename containing a
435 shell variable expands to a directory name and appends `/' to the word
436 as appropriate. The same code expands shell variables in command names
437 when performing command completion.
439 j. In Posix mode, it is now an error to attempt to define a shell function
440 with the same name as a Posix special builtin.
442 k. When compiled for strict Posix conformance, history expansion is disabled
445 l. The history expansion character (!) does not cause history expansion when
446 followed by the closing quote in a double-quoted string.
448 m. `complete' and its siblings compgen/compopt now takes a new `-o noquote'
449 option to inhibit quoting of the completions.
451 n. Setting HISTSIZE to a value less than zero causes the history list to be
452 unlimited (setting it 0 zero disables the history list).
454 o. Setting HISTFILESIZE to a value less than zero causes the history file size
455 to be unlimited (setting it to 0 causes the history file to be truncated
458 p. The `read' builtin now skips NUL bytes in the input.
460 q. There is a new `bind -X' option to print all key sequences bound to Unix
463 r. When in Posix mode, `read' is interruptible by a trapped signal. After
464 running the trap handler, read returns 128+signal and throws away any
465 partially-read input.
467 s. The command completion code skips whitespace and assignment statements
468 before looking for the command name word to be completed.
470 t. The build process has a new mechanism for constructing separate help files
471 that better reflects the current set of compilation options.
473 u. The -nt and -ot options to test now work with files with nanosecond
474 timestamp resolution.
476 v. The shell saves the command history in any shell for which history is
477 enabled and HISTFILE is set, not just interactive shells.
479 w. The shell has `nameref' variables and new -n(/+n) options to declare and
480 unset to use them, and a `test -R' option to test for them.
482 x. The shell now allows assigning, referencing, and unsetting elements of
483 indexed arrays using negative subscripts (a[-1]=2, echo ${a[-1]}) which
484 count back from the last element of the array.
486 y. The {x}<word redirection feature now allows words like {array[ind]} and
487 can use variables with special meanings to the shell (e.g., BASH_XTRACEFD).
489 z. There is a new CHILD_MAX special shell variable; its value controls the
490 number of exited child statues the shell remembers.
492 aa. There is a new configuration option (--enable-direxpand-default) that
493 causes the `direxpand' shell option to be enabled by default.
495 bb. Bash does not do anything special to ensure that the file descriptor
496 assigned to X in {x}<foo remains open after the block containing it
499 cc. The `wait' builtin has a new `-n' option to wait for the next child to
502 dd. The `printf' %(...)T format specifier now uses the current time if no
503 argument is supplied.
505 ee. There is a new variable, BASH_COMPAT, that controls the current shell
508 ff. The `popd' builtin now treats additional arguments as errors.
510 gg. The brace expansion code now treats a failed sequence expansion as a
511 simple string and will continue to expand brace terms in the remainder
514 hh. Shells started to run process substitutions now run any trap set on EXIT.
516 ii. The fc builtin now interprets -0 as the current command line.
518 jj. Completing directory names containing shell variables now adds a trailing
519 slash if the expanded result is a directory.
521 kk. `cd' has a new `-@' option to browse a file's extended attributes on
522 systems that support O_XATTR.
524 ll. The test/[/[[ `-v variable' binary operator now understands array
527 2. New Features in Readline
529 a. Readline is now more responsive to SIGHUP and other fatal signals when
530 reading input from the terminal or performing word completion but no
531 longer attempts to run any not-allowable functions from a signal handler
534 b. There are new bindable commands to search the history for the string of
535 characters between the beginning of the line and the point
536 (history-substring-search-forward, history-substring-search-backward)
538 c. Readline allows quoted strings as the values of variables when setting
539 them with `set'. As a side effect, trailing spaces and tabs are ignored
540 when setting a string variable's value.
542 d. The history library creates a backup of the history file when writing it
543 and restores the backup on a write error.
545 e. New application-settable variable: rl_filename_stat_hook: a function called
546 with a filename before using it in a call to stat(2). Bash uses it to
547 expand shell variables so things like $HOME/Downloads have a slash
550 f. New bindable function `print-last-kbd-macro', prints the most-recently-
551 defined keyboard macro in a reusable format.
553 g. New user-settable variable `colored-stats', enables use of colored text
554 to denote file types when displaying possible completions (colored analog
557 h. New user-settable variable `keyseq-timout', acts as an inter-character
558 timeout when reading input or incremental search strings.
560 i. New application-callable function: rl_clear_history. Clears the history list
561 and frees all readline-associated private data.
563 j. New user-settable variable, show-mode-in-prompt, adds a characters to the
564 beginning of the prompt indicating the current editing mode.
566 k. New application-settable variable: rl_input_available_hook; function to be
567 called when readline detects there is data available on its input file
570 l. Readline calls an application-set event hook (rl_event_hook) after it gets
571 a signal while reading input (read returns -1/EINTR but readline does not
572 handle the signal immediately) to allow the application to handle or
575 m. If the user-settable variable `history-size' is set to a value less than
576 0, the history list size is unlimited.
578 n. New application-settable variable: rl_signal_event_hook; function that is
579 called when readline is reading terminal input and read(2) is interrupted
580 by a signal. Currently not called for SIGHUP or SIGTERM.
582 o. rl_change_environment: new application-settable variable that controls
583 whether or not Readline modifies the environment (currently readline
584 modifies only LINES and COLUMNS).
586 -------------------------------------------------------------------------------
587 This is a terse description of the new features added to bash-4.2 since
588 the release of bash-4.1. As always, the manual page (doc/bash.1) is
589 the place to look for complete descriptions.
591 1. New Features in Bash
593 a. `exec -a foo' now sets $0 to `foo' in an executable shell script without a
596 b. Subshells begun to execute command substitutions or run shell functions or
597 builtins in subshells do not reset trap strings until a new trap is
598 specified. This allows $(trap) to display the caller's traps and the
599 trap strings to persist until a new trap is set.
601 c. `trap -p' will now show signals ignored at shell startup, though their
602 disposition still cannot be modified.
604 d. $'...', echo, and printf understand \uXXXX and \UXXXXXXXX escape sequences.
606 e. declare/typeset has a new `-g' option, which creates variables in the
607 global scope even when run in a shell function.
609 f. test/[/[[ have a new -v variable unary operator, which returns success if
610 `variable' has been set.
612 g. Posix parsing changes to allow `! time command' and multiple consecutive
613 instances of `!' (which toggle) and `time' (which have no cumulative
616 h. Posix change to allow `time' as a command by itself to print the elapsed
617 user, system, and real times for the shell and its children.
619 j. $((...)) is always parsed as an arithmetic expansion first, instead of as
620 a potential nested command substitution, as Posix requires.
622 k. A new FUNCNEST variable to allow the user to control the maximum shell
623 function nesting (recursive execution) level.
625 l. The mapfile builtin now supplies a third argument to the callback command:
626 the line about to be assigned to the supplied array index.
628 m. The printf builtin has a new %(fmt)T specifier, which allows time values
629 to use strftime-like formatting.
631 n. There is a new `compat41' shell option.
633 o. The cd builtin has a new Posix-mandated `-e' option.
635 p. Negative subscripts to indexed arrays, previously errors, now are treated
636 as offsets from the maximum assigned index + 1.
638 q. Negative length specifications in the ${var:offset:length} expansion,
639 previously errors, are now treated as offsets from the end of the variable.
641 r. Parsing change to allow `time -p --'.
643 s. Posix-mode parsing change to not recognize `time' as a keyword if the
644 following token begins with a `-'. This means no more Posix-mode
645 `time -p'. Posix interpretation 267.
647 t. There is a new `lastpipe' shell option that runs the last command of a
648 pipeline in the current shell context. The lastpipe option has no
649 effect if job control is enabled.
651 u. History expansion no longer expands the `$!' variable expansion.
653 v. Posix mode shells no longer exit if a variable assignment error occurs
654 with an assignment preceding a command that is not a special builtin.
656 w. Non-interactive mode shells exit if -u is enabled and an attempt is made
657 to use an unset variable with the % or # expansions, the `//', `^', or
658 `,' expansions, or the parameter length expansion.
660 x. Posix-mode shells use the argument passed to `.' as-is if a $PATH search
661 fails, effectively searching the current directory. Posix-2008 change.
663 2. New Features in Readline
665 a. The history library does not try to write the history filename in the
666 current directory if $HOME is unset. This closes a potential security
667 problem if the application does not specify a history filename.
669 b. New bindable variable `completion-display-width' to set the number of
670 columns used when displaying completions.
672 c. New bindable variable `completion-case-map' to cause case-insensitive
673 completion to treat `-' and `_' as identical.
675 d. There are new bindable vi-mode command names to avoid readline's case-
676 insensitive matching not allowing them to be bound separately.
678 e. New bindable variable `menu-complete-display-prefix' causes the menu
679 completion code to display the common prefix of the possible completions
680 before cycling through the list, instead of after.
682 -------------------------------------------------------------------------------
683 This is a terse description of the new features added to bash-4.1 since
684 the release of bash-4.0. As always, the manual page (doc/bash.1) is
685 the place to look for complete descriptions.
687 1. New Features in Bash
689 a. Here-documents within $(...) command substitutions may once more be
690 delimited by the closing right paren, instead of requiring a newline.
692 b. Bash's file status checks (executable, readable, etc.) now take file
693 system ACLs into account on file systems that support them.
695 c. Bash now passes environment variables with names that are not valid
696 shell variable names through into the environment passed to child
699 d. The `execute-unix-command' readline function now attempts to clear and
700 reuse the current line rather than move to a new one after the command
703 e. `printf -v' can now assign values to array indices.
705 f. New `complete -E' and `compopt -E' options that work on the "empty"
706 completion: completion attempted on an empty command line.
708 g. New complete/compgen/compopt -D option to define a `default' completion:
709 a completion to be invoked on command for which no completion has been
710 defined. If this function returns 124, programmable completion is
711 attempted again, allowing a user to dynamically build a set of completions
712 as completion is attempted by having the default completion function
713 install individual completion functions each time it is invoked.
715 h. When displaying associative arrays, subscripts are now quoted.
717 i. Changes to dabbrev-expand to make it more `emacs-like': no space appended
718 after matches, completions are not sorted, and most recent history entries
721 j. The [[ and (( commands are now subject to the setting of `set -e' and the
724 k. The source/. builtin now removes NUL bytes from the file before attempting
727 l. There is a new configuration option (in config-top.h) that forces bash to
728 forward all history entries to syslog.
730 m. A new variable $BASHOPTS to export shell options settable using `shopt' to
733 n. There is a new confgure option that forces the extglob option to be
736 o. New variable $BASH_XTRACEFD; when set to an integer bash will write xtrace
737 output to that file descriptor.
739 p. If the optional left-hand-side of a redirection is of the form {var}, the
740 shell assigns the file descriptor used to $var or uses $var as the file
741 descriptor to move or close, depending on the redirection operator.
743 q. The < and > operators to the [[ conditional command now do string
744 comparison according to the current locale if the compatibility level
747 r. Programmable completion now uses the completion for `b' instead of `a'
748 when completion is attempted on a line like: a $(b c.
750 s. Force extglob on temporarily when parsing the pattern argument to
751 the == and != operators to the [[ command, for compatibility.
753 t. Changed the behavior of interrupting the wait builtin when a SIGCHLD is
754 received and a trap on SIGCHLD is set to be Posix-mode only.
756 u. The read builtin has a new `-N nchars' option, which reads exactly NCHARS
757 characters, ignoring delimiters like newline.
759 v. The mapfile/readarray builtin no longer stores the commands it invokes via
760 callbacks in the history list.
762 w. There is a new `compat40' shopt option.
764 2. New Features in Readline
766 a. New bindable function: menu-complete-backward.
768 b. In the vi insertion keymap, C-n is now bound to menu-complete by default,
769 and C-p to menu-complete-backward.
771 c. When in vi command mode, repeatedly hitting ESC now does nothing, even
772 when ESC introduces a bound key sequence. This is closer to how
773 historical vi behaves.
775 d. New bindable function: skip-csi-sequence. Can be used as a default to
776 consume key sequences generated by keys like Home and End without having
779 e. New application-settable function: rl_filename_rewrite_hook. Can be used
780 to rewite or modify filenames read from the file system before they are
781 compared to the word to be completed.
783 f. New bindable variable: skip-completed-text, active when completing in the
784 middle of a word. If enabled, it means that characters in the completion
785 that match characters in the remainder of the word are "skipped" rather
786 than inserted into the line.
788 g. The pre-readline-6.0 version of menu completion is available as
789 "old-menu-complete" for users who do not like the readline-6.0 version.
791 h. New bindable variable: echo-control-characters. If enabled, and the
792 tty ECHOCTL bit is set, controls the echoing of characters corresponding
793 to keyboard-generated signals.
795 i. New bindable variable: enable-meta-key. Controls whether or not readline
796 sends the smm/rmm sequences if the terminal indicates it has a meta key
797 that enables eight-bit characters.
799 -------------------------------------------------------------------------------
800 This is a terse description of the new features added to bash-4.0 since
801 the release of bash-3.2. As always, the manual page (doc/bash.1) is
802 the place to look for complete descriptions.
804 1. New Features in Bash
806 a. When using substring expansion on the positional parameters, a starting
807 index of 0 now causes $0 to be prefixed to the list.
809 b. The `help' builtin now prints its columns with entries sorted vertically
810 rather than horizontally.
812 c. There is a new variable, $BASHPID, which always returns the process id of
815 d. There is a new `autocd' option that, when enabled, causes bash to attempt
816 to `cd' to a directory name that is supplied as the first word of a
819 e. There is a new `checkjobs' option that causes the shell to check for and
820 report any running or stopped jobs at exit.
822 f. The programmable completion code exports a new COMP_TYPE variable, set to
823 a character describing the type of completion being attempted.
825 g. The programmable completion code exports a new COMP_KEY variable, set to
826 the character that caused the completion to be invoked (e.g., TAB).
828 h. If creation of a child process fails due to insufficient resources, bash
829 will try again several times before reporting failure.
831 i. The programmable completion code now uses the same set of characters as
832 readline when breaking the command line into a list of words.
834 j. The block multiplier for the ulimit -c and -f options is now 512 when in
835 Posix mode, as Posix specifies.
837 k. Changed the behavior of the read builtin to save any partial input received
838 in the specified variable when the read builtin times out. This also
839 results in variables specified as arguments to read to be set to the empty
840 string when there is no input available. When the read builtin times out,
841 it returns an exit status greater than 128.
843 l. The shell now has the notion of a `compatibility level', controlled by
844 new variables settable by `shopt'. Setting this variable currently
845 restores the bash-3.1 behavior when processing quoted strings on the rhs
846 of the `=~' operator to the `[[' command.
848 m. The `ulimit' builtin now has new -b (socket buffer size) and -T (number
851 n. The -p option to `declare' now displays all variable values and attributes
852 (or function values and attributes if used with -f).
854 o. There is a new `compopt' builtin that allows completion functions to modify
855 completion options for existing completions or the completion currently
858 p. The `read' builtin has a new -i option which inserts text into the reply
859 buffer when using readline.
861 q. A new `-E' option to the complete builtin allows control of the default
862 behavior for completion on an empty line.
864 r. There is now limited support for completing command name words containing
867 s. Changed format of internal help documentation for all builtins to roughly
868 follow man page format.
870 t. The `help' builtin now has a new -d option, to display a short description,
871 and a -m option, to print help information in a man page-like format.
873 u. There is a new `mapfile' builtin to populate an array with lines from a
874 given file. The name `readarray' is a synonym.
876 v. If a command is not found, the shell attempts to execute a shell function
877 named `command_not_found_handle', supplying the command words as the
880 w. There is a new shell option: `globstar'. When enabled, the globbing code
881 treats `**' specially -- it matches all directories (and files within
882 them, when appropriate) recursively.
884 x. There is a new shell option: `dirspell'. When enabled, the filename
885 completion code performs spelling correction on directory names during
888 y. The `-t' option to the `read' builtin now supports fractional timeout
891 z. Brace expansion now allows zero-padding of expanded numeric values and
892 will add the proper number of zeroes to make sure all values contain the
893 same number of digits.
895 aa. There is a new bash-specific bindable readline function: `dabbrev-expand'.
896 It uses menu completion on a set of words taken from the history list.
898 bb. The command assigned to a key sequence with `bind -x' now sets two new
899 variables in the environment of the executed command: READLINE_LINE_BUFFER
900 and READLINE_POINT. The command can change the current readline line
901 and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT,
904 cc. There is a new &>> redirection operator, which appends the standard output
905 and standard error to the named file.
907 dd. The parser now understands `|&' as a synonym for `2>&1 |', which redirects
908 the standard error for a command through a pipe.
910 ee. The new `;&' case statement action list terminator causes execution to
911 continue with the action associated with the next pattern in the
912 statement rather than terminating the command.
914 ff. The new `;;&' case statement action list terminator causes the shell to
915 test the next set of patterns after completing execution of the current
916 action, rather than terminating the command.
918 gg. The shell understands a new variable: PROMPT_DIRTRIM. When set to an
919 integer value greater than zero, prompt expansion of \w and \W will
920 retain only that number of trailing pathname components and replace
921 the intervening characters with `...'.
923 hh. There are new case-modifying word expansions: uppercase (^[^]) and
924 lowercase (,[,]). They can work on either the first character or
925 array element, or globally. They accept an optional shell pattern
926 that determines which characters to modify. There is an optionally-
927 configured feature to include capitalization operators.
929 ii. The shell provides associative array variables, with the appropriate
930 support to create, delete, assign values to, and expand them.
932 jj. The `declare' builtin now has new -l (convert value to lowercase upon
933 assignment) and -u (convert value to uppercase upon assignment) options.
934 There is an optionally-configurable -c option to capitalize a value at
937 kk. There is a new `coproc' reserved word that specifies a coprocess: an
938 asynchronous command run with two pipes connected to the creating shell.
939 Coprocs can be named. The input and output file descriptors and the
940 PID of the coprocess are available to the calling shell in variables
941 with coproc-specific names.
943 ll. A value of 0 for the -t option to `read' now returns success if there is
944 input available to be read from the specified file descriptor.
946 mm. CDPATH and GLOBIGNORE are ignored when the shell is running in privileged
949 nn. New bindable readline functions shell-forward-word and shell-backward-word,
950 which move forward and backward words delimited by shell metacharacters
951 and honor shell quoting.
953 oo. New bindable readline functions shell-backward-kill-word and shell-kill-word
954 which kill words backward and forward, but use the same word boundaries
955 as shell-forward-word and shell-backward-word.
957 2. New Features in Readline
959 a. A new variable, rl_sort_completion_matches; allows applications to inhibit
960 match list sorting (but beware: some things don't work right if
961 applications do this).
963 b. A new variable, rl_completion_invoking_key; allows applications to discover
964 the key that invoked rl_complete or rl_menu_complete.
966 c. The functions rl_block_sigint and rl_release_sigint are now public and
967 available to calling applications who want to protect critical sections
970 d. The functions rl_save_state and rl_restore_state are now public and
971 available to calling applications; documented rest of readline's state
974 e. A new user-settable variable, `history-size', allows setting the maximum
975 number of entries in the history list.
977 f. There is a new implementation of menu completion, with several improvements
978 over the old; the most notable improvement is a better `completions
981 g. The menu completion code now uses the rl_menu_completion_entry_function
982 variable, allowing applications to provide their own menu completion
985 h. There is support for replacing a prefix of a pathname with a `...' when
986 displaying possible completions. This is controllable by setting the
987 `completion-prefix-display-length' variable. Matches with a common prefix
988 longer than this value have the common prefix replaced with `...'.
990 i. There is a new `revert-all-at-newline' variable. If enabled, readline will
991 undo all outstanding changes to all history lines when `accept-line' is
994 j. If the kernel supports it, readline displays special characters
995 corresponding to a keyboard-generated signal when the signal is received.
997 -------------------------------------------------------------------------------
998 This is a terse description of the new features added to bash-3.2 since
999 the release of bash-3.1. As always, the manual page (doc/bash.1) is
1000 the place to look for complete descriptions.
1002 1. New Features in Bash
1004 a. Changed the parameter pattern replacement functions to not anchor the
1005 pattern at the beginning of the string if doing global replacement - that
1006 combination doesn't make any sense.
1008 b. When running in `word expansion only' mode (--wordexp option), inhibit
1009 process substitution.
1011 c. Loadable builtins now work on MacOS X 10.[34].
1013 d. Shells running in posix mode no longer set $HOME, as POSIX requires.
1015 e. The code that checks for binary files being executed as shell scripts now
1016 checks only for NUL rather than any non-printing character.
1018 f. Quoting the string argument to the [[ command's =~ operator now forces
1019 string matching, as with the other pattern-matching operators.
1021 2. New Features in Readline
1023 a. Calling applications can now set the keyboard timeout to 0, allowing
1026 b. The value of SYS_INPUTRC (configurable at compilation time) is now used as
1027 the default last-ditch startup file.
1029 c. The history file reading functions now allow windows-like \r\n line
1032 -------------------------------------------------------------------------------
1033 This is a terse description of the new features added to bash-3.1 since
1034 the release of bash-3.0. As always, the manual page (doc/bash.1) is
1035 the place to look for complete descriptions.
1037 1. New Features in Bash
1039 a. Bash now understands LC_TIME as a special variable so that time display
1040 tracks the current locale.
1042 b. BASH_ARGC, BASH_ARGV, BASH_SOURCE, and BASH_LINENO are no longer created
1043 as `invisible' variables and may not be unset.
1045 c. In POSIX mode, if `xpg_echo' option is enabled, the `echo' builtin doesn't
1046 try to interpret any options at all, as POSIX requires.
1048 d. The `bg' builtin now accepts multiple arguments, as POSIX seems to specify.
1050 e. Fixed vi-mode word completion and glob expansion to perform tilde
1053 f. The `**' mathematic exponentiation operator is now right-associative.
1055 g. The `ulimit' builtin has new options: -i (max number of pending signals),
1056 -q (max size of POSIX message queues), and -x (max number of file locks).
1058 h. A bare `%' once again expands to the current job when used as a job
1061 i. The `+=' assignment operator (append to the value of a string or array) is
1062 now supported for assignment statements and arguments to builtin commands
1063 that accept assignment statements.
1065 j. BASH_COMMAND now preserves its value when a DEBUG trap is executed.
1067 k. The `gnu_errfmt' option is enabled automatically if the shell is running
1068 in an emacs terminal window.
1070 l. New configuration option: --single-help-strings. Causes long help text
1071 to be written as a single string; intended to ease translation.
1073 m. The COMP_WORDBREAKS variable now causes the list of word break characters
1074 to be emptied when the variable is unset.
1076 n. An unquoted expansion of $* when $IFS is empty now causes the positional
1077 parameters to be concatenated if the expansion doesn't undergo word
1080 o. Bash now inherits $_ from the environment if it appears there at startup.
1082 p. New shell option: nocasematch. If non-zero, shell pattern matching ignores
1083 case when used by `case' and `[[' commands.
1085 q. The `printf' builtin takes a new option: -v var. That causes the output
1086 to be placed into var instead of on stdout.
1088 r. By default, the shell no longer reports processes dying from SIGPIPE.
1090 s. Bash now sets the extern variable `environ' to the export environment it
1091 creates, so C library functions that call getenv() (and can't use the
1092 shell-provided replacement) get current values of environment variables.
1094 t. A new configuration option, `--enable-strict-posix-default', which will
1095 build bash to be POSIX conforming by default.
1097 u. If compiled for strict POSIX conformance, LINES and COLUMNS may now
1098 override the true terminal size.
1100 2. New Features in Readline
1102 a. The key sequence sent by the keypad `delete' key is now automatically
1103 bound to delete-char.
1105 b. A negative argument to menu-complete now cycles backward through the
1108 c. A new bindable readline variable: bind-tty-special-chars. If non-zero,
1109 readline will bind the terminal special characters to their readline
1110 equivalents when it's called (on by default).
1112 d. New bindable command: vi-rubout. Saves deleted text for possible
1113 reinsertion, as with any vi-mode `text modification' command; `X' is bound
1114 to this in vi command mode.
1116 e. A new external application-controllable variable that allows the LINES
1117 and COLUMNS environment variables to set the window size regardless of
1118 what the kernel returns: rl_prefer_env_winsize
1120 -------------------------------------------------------------------------------
1121 This is a terse description of the new features added to bash-3.0 since
1122 the release of bash-2.05b. As always, the manual page (doc/bash.1) is
1123 the place to look for complete descriptions.
1125 1. New Features in Bash
1127 a. ANSI string expansion now implements the \x{hexdigits} escape.
1129 b. There is a new loadable `strftime' builtin.
1131 c. New variable, COMP_WORDBREAKS, which controls the readline completer's
1132 idea of word break characters.
1134 d. The `type' builtin no longer reports on aliases unless alias expansion
1135 will actually be performed.
1137 e. HISTCONTROL is now a colon-separated list of values, which permits
1138 more extensibility and backwards compatibility.
1140 f. HISTCONTROL may now include the `erasedups' option, which causes all lines
1141 matching a line being added to be removed from the history list.
1143 g. `configure' has a new `--enable-multibyte' argument that permits multibyte
1144 character support to be disabled even on systems that support it.
1146 h. New variables to support the bash debugger: BASH_ARGC, BASH_ARGV,
1147 BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING,
1150 i. FUNCNAME has been changed to support the debugger: it's now an array
1153 j. for, case, select, arithmetic commands now keep line number information
1156 k. There is a new `RETURN' trap executed when a function or sourced script
1157 returns (not inherited child processes; inherited by command substitution
1158 if function tracing is enabled and the debugger is active).
1160 l. New invocation option: --debugger. Enables debugging and turns on new
1161 `extdebug' shell option.
1163 m. New `functrace' and `errtrace' options to `set -o' cause DEBUG and ERR
1164 traps, respectively, to be inherited by shell functions. Equivalent to
1165 `set -T' and `set -E' respectively. The `functrace' option also controls
1166 whether or not the DEBUG trap is inherited by sourced scripts.
1168 n. The DEBUG trap is run before binding the variable and running the action
1169 list in a `for' command, binding the selection variable and running the
1170 query in a `select' command, and before attempting a match in a `case'
1173 o. New `--enable-debugger' option to `configure' to compile in the debugger
1176 p. `declare -F' now prints out extra line number and source file information
1177 if the `extdebug' option is set.
1179 q. If `extdebug' is enabled, a non-zero return value from a DEBUG trap causes
1180 the next command to be skipped, and a return value of 2 while in a
1181 function or sourced script forces a `return'.
1183 r. New `caller' builtin to provide a call stack for the bash debugger.
1185 s. The DEBUG trap is run just before the first command in a function body is
1186 executed, for the debugger.
1188 t. `for', `select', and `case' command heads are printed when `set -x' is
1191 u. There is a new {x..y} brace expansion, which is shorthand for {x.x+1,
1192 x+2,...,y}. x and y can be integers or single characters; the sequence
1193 may ascend or descend; the increment is always 1.
1195 v. New ksh93-like ${!array[@]} expansion, expands to all the keys (indices)
1198 w. New `force_fignore' shopt option; if enabled, suffixes specified by
1199 FIGNORE cause words to be ignored when performing word completion even
1200 if they're the only possibilities.
1202 x. New `gnu_errfmt' shopt option; if enabled, error messages follow the `gnu
1203 style' (filename:lineno:message) format.
1205 y. New `-o bashdefault' option to complete and compgen; if set, causes the
1206 whole set of bash completions to be performed if the compspec doesn't
1209 z. New `-o plusdirs' option to complete and compgen; if set, causes directory
1210 name completion to be performed and the results added to the rest of the
1211 possible completions.
1213 aa. `kill' is available as a builtin even when the shell is built without
1216 bb. New HISTTIMEFORMAT variable; value is a format string to pass to
1217 strftime(3). If set and not null, the `history' builtin prints out
1218 timestamp information according to the specified format when displaying
1219 history entries. If set, bash tells the history library to write out
1220 timestamp information when the history file is written.
1222 cc. The [[ ... ]] command has a new binary `=~' operator that performs
1223 extended regular expression (egrep-like) matching.
1225 dd. `configure' has a new `--enable-cond-regexp' option (enabled by default)
1226 to enable the =~ operator and regexp matching in [[ ... ]].
1228 ee. Subexpressions matched by the =~ operator are placed in the new
1229 BASH_REMATCH array variable.
1231 ff. New `failglob' option that causes an expansion error when pathname
1232 expansion fails to produce a match.
1234 gg. New `set -o pipefail' option that causes a pipeline to return a failure
1235 status if any of the processes in the pipeline fail, not just the last
1238 hh. printf builtin understands two new escape sequences: \" and \?.
1240 ii. `echo -e' understands two new escape sequences: \" and \?.
1242 jj. The GNU `gettext' package and libintl have been integrated; the shell's
1243 messages can be translated into different languages.
1245 kk. The `\W' prompt expansion now abbreviates $HOME as `~', like `\w'.
1247 ll. The error message printed when bash cannot open a shell script supplied
1248 as argument 1 now includes the name of the shell, to better identify
1249 the error as coming from bash.
1251 mm. The parameter pattern removal and substitution expansions are now much
1252 faster and more efficient when using multibyte characters.
1254 nn. The `jobs', `kill', and `wait' builtins now accept job control notation
1255 even if job control is not enabled.
1257 oo. The historical behavior of `trap' that allows a missing `action' argument
1258 to cause each specified signal's handling to be reset to its default is
1259 now only supported when `trap' is given a single non-option argument.
1261 2. New Features in Readline
1263 a. History expansion has a new `a' modifier equivalent to the `g' modifier
1264 for compatibility with the BSD csh.
1266 b. History expansion has a new `G' modifier equivalent to the BSD csh `g'
1267 modifier, which performs a substitution once per word.
1269 c. All non-incremental search operations may now undo the operation of
1270 replacing the current line with the history line.
1272 d. The text inserted by an `a' command in vi mode can be reinserted with
1275 e. New bindable variable, `show-all-if-unmodified'. If set, the readline
1276 completer will list possible completions immediately if there is more
1277 than one completion and partial completion cannot be performed.
1279 f. There is a new application-callable `free_history_entry()' function.
1281 g. History list entries now contain timestamp information; the history file
1282 functions know how to read and write timestamp information associated
1285 h. Four new key binding functions have been added:
1287 rl_bind_key_if_unbound()
1288 rl_bind_key_if_unbound_in_map()
1289 rl_bind_keyseq_if_unbound()
1290 rl_bind_keyseq_if_unbound_in_map()
1292 i. New application variable, rl_completion_quote_character, set to any
1293 quote character readline finds before it calls the application completion
1296 j. New application variable, rl_completion_suppress_quote, settable by an
1297 application completion function. If set to non-zero, readline does not
1298 attempt to append a closing quote to a completed word.
1300 k. New application variable, rl_completion_found_quote, set to a non-zero
1301 value if readline determines that the word to be completed is quoted.
1302 Set before readline calls any application completion function.
1304 l. New function hook, rl_completion_word_break_hook, called when readline
1305 needs to break a line into words when completion is attempted. Allows
1306 the word break characters to vary based on position in the line.
1308 m. New bindable command: unix-filename-rubout. Does the same thing as
1309 unix-word-rubout, but adds `/' to the set of word delimiters.
1311 n. When listing completions, directories have a `/' appended if the
1312 `mark-directories' option has been enabled.
1314 -------------------------------------------------------------------------------
1315 This is a terse description of the new features added to bash-2.05b since
1316 the release of bash-2.05a. As always, the manual page (doc/bash.1) is
1317 the place to look for complete descriptions.
1319 1. New Features in Bash
1321 a. If set, TMOUT is the default timeout for the `read' builtin.
1323 b. `type' has two new options: `-f' suppresses shell function lookup, and
1324 `-P' forces a $PATH search.
1326 c. New code to handle multibyte characters.
1328 d. `select' was changed to be more ksh-compatible, in that the menu is
1329 reprinted each time through the loop only if REPLY is set to NULL.
1330 The previous behavior is available as a compile-time option.
1332 e. `complete -d' and `complete -o dirnames' now force a slash to be
1333 appended to names which are symlinks to directories.
1335 f. There is now a bindable edit-and-execute-command readline command,
1336 like the vi-mode `v' command, bound to C-xC-e in emacs mode.
1338 g. Added support for ksh93-like [:word:] character class in pattern matching.
1340 h. The $'...' quoting construct now expands \cX to Control-X.
1342 i. A new \D{...} prompt expansion; passes the `...' to strftime and inserts
1343 the result into the expanded prompt.
1345 j. The shell now performs arithmetic in the largest integer size the
1346 machine supports (intmax_t), instead of long.
1348 k. If a numeric argument is supplied to one of the bash globbing completion
1349 functions, a `*' is appended to the word before expansion is attempted.
1351 l. The bash globbing completion functions now allow completions to be listed
1352 with double tabs or if `show-all-if-ambiguous' is set.
1354 m. New `-o nospace' option for `complete' and `compgen' builtins; suppresses
1355 readline's appending a space to the completed word.
1357 n. New `here-string' redirection operator: <<< word.
1359 o. When displaying variables, function attributes and definitions are shown
1360 separately, allowing them to be re-used as input (attempting to re-use
1361 the old output would result in syntax errors).
1363 p. There is a new configuration option `--enable-mem-scramble', controls
1364 bash malloc behavior of writing garbage characters into memory at
1365 allocation and free time.
1367 q. The `complete' and `compgen' builtins now have a new `-s/-A service'
1368 option to complete on names from /etc/services.
1370 r. `read' has a new `-u fd' option to read from a specified file descriptor.
1372 s. Fix the completion code so that expansion errors in a directory name
1373 don't cause a longjmp back to the command loop.
1375 t. Fixed word completion inside command substitution to work a little more
1378 u. The `printf' %q format specifier now uses $'...' quoting to print the
1379 argument if it contains non-printing characters.
1381 v. The `declare' and `typeset' builtins have a new `-t' option. When applied
1382 to functions, it causes the DEBUG trap to be inherited by the named
1383 function. Currently has no effect on variables.
1385 w. The DEBUG trap is now run *before* simple commands, ((...)) commands,
1386 [[...]] conditional commands, and for ((...)) loops.
1388 x. The expansion of $LINENO inside a shell function is only relative to the
1389 function start if the shell is interactive -- if the shell is running a
1390 script, $LINENO expands to the line number in the script. This is as
1391 POSIX-2001 requires.
1393 y. The bash debugger in examples/bashdb has been modified to work with the
1394 new DEBUG trap semantics, the command set has been made more gdb-like,
1395 and the changes to $LINENO make debugging functions work better. Code
1398 z. New [n]<&word- and [n]>&word- redirections from ksh93 -- move fds (dup
1401 aa. There is a new `-l' invocation option, equivalent to `--login'.
1403 bb. The `hash' builtin has a new `-l' option to list contents in a reusable
1404 format, and a `-d' option to remove a name from the hash table.
1406 cc. There is now support for placing the long help text into separate files
1407 installed into ${datadir}/bash. Not enabled by default; can be turned
1408 on with `--enable-separate-helpfiles' option to configure.
1410 dd. All builtins that take operands accept a `--' pseudo-option, except
1413 ee. The `echo' builtin now accepts \0xxx (zero to three octal digits following
1414 the `0') in addition to \xxx (one to three octal digits) for SUSv3/XPG6/
1415 POSIX.1-2001 compliance.
1418 2. New Features in Readline
1420 a. Support for key `subsequences': allows, e.g., ESC and ESC-a to both
1421 be bound to readline functions. Now the arrow keys may be used in vi
1424 b. When listing completions, and the number of lines displayed is more than
1425 the screen length, readline uses an internal pager to display the results.
1426 This is controlled by the `page-completions' variable (default on).
1428 c. New code to handle editing and displaying multibyte characters.
1430 d. The behavior introduced in bash-2.05a of deciding whether or not to
1431 append a slash to a completed name that is a symlink to a directory has
1432 been made optional, controlled by the `mark-symlinked-directories'
1433 variable (default is the 2.05a behavior).
1435 e. The `insert-comment' command now acts as a toggle if given a numeric
1436 argument: if the first characters on the line don't specify a
1437 comment, insert one; if they do, delete the comment text
1439 f. New application-settable completion variable:
1440 rl_completion_mark_symlink_dirs, allows an application's completion
1441 function to temporarily override the user's preference for appending
1442 slashes to names which are symlinks to directories.
1444 g. New function available to application completion functions:
1445 rl_completion_mode, to tell how the completion function was invoked
1446 and decide which argument to supply to rl_complete_internal (to list
1449 h. Readline now has an overwrite mode, toggled by the `overwrite-mode'
1450 bindable command, which could be bound to `Insert'.
1452 i. New application-settable completion variable:
1453 rl_completion_suppress_append, inhibits appending of
1454 rl_completion_append_character to completed words.
1456 j. New key bindings when reading an incremental search string: ^W yanks
1457 the currently-matched word out of the current line into the search
1458 string; ^Y yanks the rest of the current line into the search string,
1459 DEL or ^H deletes characters from the search string.
1461 -------------------------------------------------------------------------------
1462 This is a terse description of the new features added to bash-2.05a since
1463 the release of bash-2.05. As always, the manual page (doc/bash.1) is
1464 the place to look for complete descriptions.
1466 1. New Features in Bash
1468 a. Added support for DESTDIR installation root prefix, so you can do a
1469 `make install DESTDIR=bash-root' and do easier binary packaging.
1471 b. Added support for builtin printf "'" flag character as per latest POSIX
1474 c. Support for POSIX.2 printf(1) length specifiers `j', `t', and `z' (from
1477 d. New autoconf macro, RL_LIB_READLINE_VERSION, for use by other applications
1478 (bash doesn't use very much of what it returns).
1480 e. `set [-+]o nolog' is recognized as required by the latest POSIX drafts,
1483 f. New read-only `shopt' option: login_shell. Set to non-zero value if the
1484 shell is a login shell.
1486 g. New `\A' prompt string escape sequence; expands to time in 24 HH:MM format.
1488 h. New `-A group/-g' option to complete and compgen; does group name
1491 i. New `-t' option to `hash' to list hash values for each filename argument.
1493 j. New [-+]O invocation option to set and unset `shopt' options at startup.
1495 k. configure's `--with-installed-readline' option now takes an optional
1496 `=PATH' suffix to set the root of the tree where readline is installed
1499 l. The ksh-like `ERR' trap has been added. The `ERR' trap will be run
1500 whenever the shell would have exited if the -e option were enabled.
1501 It is not inherited by shell functions.
1503 m. `readonly', `export', and `declare' now print variables which have been
1504 given attributes but not set by assigning a value as just a command and
1505 a variable name (like `export foo') when listing, as the latest POSIX
1508 n. `bashbug' now requires that the subject be changed from the default.
1510 o. configure has a new `--enable-largefile' option, like other GNU utilities.
1512 p. `for' loops now allow empty word lists after `in', like the latest POSIX
1515 q. The builtin `ulimit' now takes two new non-numeric arguments: `hard',
1516 meaning the current hard limit, and `soft', meaning the current soft
1517 limit, in addition to `unlimited'
1519 r. `ulimit' now prints the option letter associated with a particular
1520 resource when printing more than one limit.
1522 s. `ulimit' prints `hard' or `soft' when a value is not `unlimited' but is
1523 one of RLIM_SAVED_MAX or RLIM_SAVED_CUR, respectively.
1525 t. The `printf' builtin now handles the %a and %A conversions if they're
1526 implemented by printf(3).
1528 u. The `printf' builtin now handles the %F conversion (just about like %f).
1530 v. The `printf' builtin now handles the %n conversion like printf(3). The
1531 corresponding argument is the name of a shell variable to which the
1534 2. New Features in Readline
1536 a. Added extern declaration for rl_get_termcap to readline.h, making it a
1537 public function (it was always there, just not in readline.h).
1539 b. New #defines in readline.h: RL_READLINE_VERSION, currently 0x0402,
1540 RL_VERSION_MAJOR, currently 4, and RL_VERSION_MINOR, currently 2.
1542 c. New readline variable: rl_readline_version, mirrors RL_READLINE_VERSION.
1544 d. New bindable boolean readline variable: match-hidden-files. Controls
1545 completion of files beginning with a `.' (on Unix). Enabled by default.
1547 e. The history expansion code now allows any character to terminate a
1548 `:first-' modifier, like csh.
1550 f. New bindable variable `history-preserve-point'. If set, the history
1551 code attempts to place the user at the same location on each history
1552 line retrived with previous-history or next-history.
1554 -------------------------------------------------------------------------------
1555 This is a terse description of the new features added to bash-2.05 since
1556 the release of bash-2.04. As always, the manual page (doc/bash.1) is
1557 the place to look for complete descriptions.
1559 1. New Features in Bash
1561 a. Added a new `--init-file' invocation argument as a synonym for `--rcfile',
1562 per the new GNU coding standards.
1564 b. The /dev/tcp and /dev/udp redirections now accept service names as well as
1567 c. `complete' and `compgen' now take a `-o value' option, which controls some
1568 of the aspects of that compspec. Valid values are:
1570 default - perform bash default completion if programmable
1571 completion produces no matches
1572 dirnames - perform directory name completion if programmable
1573 completion produces no matches
1574 filenames - tell readline that the compspec produces filenames,
1575 so it can do things like append slashes to
1576 directory names and suppress trailing spaces
1578 d. A new loadable builtin, realpath, which canonicalizes and expands symlinks
1579 in pathname arguments.
1581 e. When `set' is called without options, it prints function defintions in a
1582 way that allows them to be reused as input. This affects `declare' and
1583 `declare -p' as well. This only happens when the shell is not in POSIX
1584 mode, since POSIX.2 forbids this behavior.
1586 f. Bash-2.05 once again honors the current locale setting when processing
1587 ranges within pattern matching bracket expressions (e.g., [A-Z]).
1589 2. New Features in Readline
1591 a. The blink timeout for paren matching is now settable by applications,
1592 via the rl_set_paren_blink_timeout() function.
1594 b. _rl_executing_macro has been renamed to rl_executing_macro, which means
1595 it's now part of the public interface.
1597 c. Readline has a new variable, rl_readline_state, which is a bitmap that
1598 encapsulates the current state of the library; intended for use by
1599 callbacks and hook functions.
1601 d. New application-callable function rl_set_prompt(const char *prompt):
1602 expands its prompt string argument and sets rl_prompt to the result.
1604 e. New application-callable function rl_set_screen_size(int rows, int cols):
1605 public method for applications to set readline's idea of the screen
1608 f. New function, rl_get_screen_size (int *rows, int *columns), returns
1609 readline's idea of the screen dimensions.
1611 g. The timeout in rl_gather_tyi (readline keyboard input polling function)
1612 is now settable via a function (rl_set_keyboard_input_timeout()).
1614 h. Renamed the max_input_history variable to history_max_entries; the old
1615 variable is maintained for backwards compatibility.
1617 i. The list of characters that separate words for the history tokenizer is
1618 now settable with a variable: history_word_delimiters. The default
1621 -------------------------------------------------------------------------------
1622 This is a terse description of the new features added to bash-2.04 since
1623 the release of bash-2.03. As always, the manual page (doc/bash.1) is
1624 the place to look for complete descriptions.
1626 1. New Features in Bash
1628 a. The history builtin has a `-d offset' option to delete the history entry
1629 at position `offset'.
1631 b. The prompt expansion code has two new escape sequences: \j, the number of
1632 active jobs; and \l, the basename of the shell's tty device name.
1634 c. The `bind' builtin has a new `-x' option to bind key sequences to shell
1637 d. There is a new shell option, no_empty_command_completion, which, when
1638 enabled, disables command completion when TAB is typed on an empty line.
1640 e. The `help' builtin has a `-s' option to just print a builtin's usage
1643 f. There are several new arithmetic operators: id++, id-- (variable
1644 post-increment/decrement), ++id, --id (variable pre-increment/decrement),
1645 expr1 , expr2 (comma operator).
1647 g. There is a new ksh-93 style arithmetic for command:
1648 for ((expr1 ; expr2; expr3 )); do list; done
1650 h. The `read' builtin has a number of new options:
1651 -t timeout only wait timeout seconds for input
1652 -n nchars only read nchars from input instead of a full line
1653 -d delim read until delim rather than newline
1654 -s don't echo input chars as they are read
1656 i. The redirection code now handles several filenames specially:
1657 /dev/fd/N, /dev/stdin, /dev/stdout, and /dev/stderr, whether or
1658 not they are present in the file system.
1660 j. The redirection code now recognizes pathnames of the form
1661 /dev/tcp/host/port and /dev/udp/host/port, and tries to open a socket
1662 of the appropriate type to the specified port on the specified host.
1664 k. The ksh-93 ${!prefix*} expansion, which expands to the names of all
1665 shell variables with prefix PREFIX, has been implemented.
1667 l. There is a new dynamic variable, FUNCNAME, which expands to the name of
1668 a currently-executing function. Assignments to FUNCNAME have no effect.
1670 m. The GROUPS variable is no longer readonly; assignments to it are silently
1671 discarded. This means it can be unset.
1673 n. A new programmable completion facility, with two new builtin commands:
1674 complete and compgen.
1676 o. configure has a new option, `--enable-progcomp', to compile in the
1677 programmable completion features (enabled by default).
1679 p. `shopt' has a new option, `progcomp', to enable and disable programmable
1680 completion at runtime.
1682 q. Unsetting HOSTFILE now clears the list of hostnames used for completion.
1684 r. configure has a new option, `--enable-bash-malloc', replacing the old
1685 `--with-gnu-malloc' (which is still present for backwards compatibility).
1687 s. There is a new manual page describing rbash, the restricted shell.
1689 t. `bashbug' has new `--help' and `--version' options.
1691 u. `shopt' has a new `xpg_echo' option, which controls the behavior of
1692 `echo' with respect to backslash-escaped characters at runtime.
1694 v. If NON_INTERACTIVE_LOGIN_SHELLS is defined, all login shells read the
1695 startup files, even if they are not interactive.
1697 w. The LC_NUMERIC variable is now treated specially, and used to set the
1698 LC_NUMERIC locale category for number formatting, e.g., when `printf'
1699 displays floating-point numbers.
1701 2. New features in Readline
1703 a. Parentheses matching is now always compiled into readline, and enabled
1704 or disabled when the value of the `blink-matching-paren' variable is
1707 b. MS-DOS systems now use ~/_inputrc as the last-ditch inputrc filename.
1709 c. MS-DOS systems now use ~/_history as the default history file.
1711 d. history-search-{forward,backward} now leave the point at the end of the
1712 line when the string to search for is empty, like
1713 {reverse,forward}-search-history.
1715 e. history-search-{forward,backward} now leave the last history line found
1716 in the readline buffer if the second or subsequent search fails.
1718 f. New function for use by applications: rl_on_new_line_with_prompt, used
1719 when an application displays the prompt itself before calling readline().
1721 g. New variable for use by applications: rl_already_prompted. An application
1722 that displays the prompt itself before calling readline() must set this to
1725 h. A new variable, rl_gnu_readline_p, always 1. The intent is that an
1726 application can verify whether or not it is linked with the `real'
1727 readline library or some substitute.
1729 -------------------------------------------------------------------------------
1730 This is a terse description of the new features added to bash-2.03 since
1731 the release of bash-2.02. As always, the manual page (doc/bash.1) is
1732 the place to look for complete descriptions.
1734 1. New Features in Bash
1736 a. New `shopt' option, `restricted_shell', indicating whether or not the
1737 shell was started in restricted mode, for use in startup files.
1739 b. Filename generation is now performed on the words between ( and ) in
1740 array assignments (which it probably should have done all along).
1742 c. OLDPWD is now auto-exported, as POSIX.2 seems to require.
1744 d. ENV and BASH_ENV are read-only variables in a restricted shell.
1746 e. A change was made to the startup file code so that any shell begun with
1747 the `--login' option, even non-interactive shells, will source the login
1748 shell startup files.
1750 2. New Features in Readline
1752 a. Many changes to the signal handling:
1753 o Readline now catches SIGQUIT and cleans up the tty before returning;
1754 o A new variable, rl_catch_signals, is available to application writers
1755 to indicate to readline whether or not it should install its own
1756 signal handlers for SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP,
1757 SIGTTIN, and SIGTTOU;
1758 o A new variable, rl_catch_sigwinch, is available to application
1759 writers to indicate to readline whether or not it should install its
1760 own signal handler for SIGWINCH, which will chain to the calling
1761 applications's SIGWINCH handler, if one is installed;
1762 o There is a new function, rl_free_line_state, for application signal
1763 handlers to call to free up the state associated with the current
1764 line after receiving a signal;
1765 o There is a new function, rl_cleanup_after_signal, to clean up the
1766 display and terminal state after receiving a signal;
1767 o There is a new function, rl_reset_after_signal, to reinitialize the
1768 terminal and display state after an application signal handler
1769 returns and readline continues
1771 b. There is a new function, rl_resize_terminal, to reset readline's idea of
1772 the screen size after a SIGWINCH.
1774 c. New public functions: rl_save_prompt and rl_restore_prompt. These were
1775 previously private functions with a `_' prefix.
1777 d. New function hook: rl_pre_input_hook, called just before readline starts
1778 reading input, after initialization.
1780 e. New function hook: rl_display_matches_hook, called when readline would
1781 display the list of completion matches. The new function
1782 rl_display_match_list is what readline uses internally, and is available
1783 for use by application functions called via this hook.
1785 f. New bindable function, delete-char-or-list, like tcsh.
1787 g. A new variable, rl_erase_empty_line, which, if set by an application using
1788 readline, will cause readline to erase, prompt and all, lines on which the
1789 only thing typed was a newline.
1791 h. New bindable variable: `isearch-terminators'.
1793 i. New bindable function: `forward-backward-delete-char' (unbound by default).
1795 -------------------------------------------------------------------------------
1796 This is a terse description of the new features added to bash-2.02 since
1797 the release of bash-2.01.1. As always, the manual page (doc/bash.1) is
1798 the place to look for complete descriptions.
1800 1. New Features in Bash
1802 a. A new version of malloc, based on the older GNU malloc, that has many
1803 changes, is more page-based, is more conservative with memory usage,
1804 and does not `orphan' large blocks when they are freed.
1806 b. A new version of gmalloc, based on the old GLIBC malloc, with many
1807 changes and range checking included by default.
1809 c. A new implementation of fnmatch(3) that includes full POSIX.2 Basic
1810 Regular Expression matching, including character classes, collating
1811 symbols, equivalence classes, and support for case-insensitive pattern
1814 d. ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been
1815 implemented, controlled by a new `shopt' option, `extglob'.
1817 e. There is a new ksh-like `[[' compound command, which implements
1818 extended `test' functionality.
1820 f. There is a new `printf' builtin, implemented according to the POSIX.2
1823 g. There is a new feature for command substitution: $(< filename) now expands
1824 to the contents of `filename', with any trailing newlines removed
1825 (equivalent to $(cat filename)).
1827 h. There are new tilde prefixes which expand to directories from the
1830 i. There is a new `**' arithmetic operator to do exponentiation.
1832 j. There are new configuration options to control how bash is linked:
1833 `--enable-profiling', to allow bash to be profiled with gprof, and
1834 `--enable-static-link', to allow bash to be linked statically.
1836 k. There is a new configuration option, `--enable-cond-command', which
1837 controls whether or not the `[[' command is included. It is on by
1840 l. There is a new configuration option, `--enable-extended-glob', which
1841 controls whether or not the ksh extended globbing feature is included.
1842 It is enabled by default.
1844 m. There is a new configuration #define in config.h.top that, when enabled,
1845 will cause all login shells to source /etc/profile and one of the user-
1846 specific login shell startup files, whether or not the shell is
1849 n. There is a new invocation option, `--dump-po-strings', to dump
1850 a shell script's translatable strings ($"...") in GNU `po' format.
1852 o. There is a new `shopt' option, `nocaseglob', to enable case-insensitive
1853 pattern matching when globbing filenames and using the `case' construct.
1855 p. There is a new `shopt' option, `huponexit', which, when enabled, causes
1856 the shell to send SIGHUP to all jobs when an interactive login shell
1859 q. `bind' has a new `-u' option, which takes a readline function name as an
1860 argument and unbinds all key sequences bound to that function in a
1863 r. `disown' now has `-a' and `-r' options, to limit operation to all jobs
1864 and running jobs, respectively.
1866 s. The `shopt' `-p' option now causes output to be displayed in a reusable
1869 t. `test' has a new `-N' option, which returns true if the filename argument
1870 has been modified since it was last accessed.
1872 u. `umask' now has a `-p' option to print output in a reusable format.
1874 v. A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...'
1875 translation code. It expands to the character whose ascii code is NNN
1878 w. The prompt string expansion code has a new `\r' escape sequence.
1880 x. The shell may now be cross-compiled for the CYGWIN32 environment on
1883 2. New Features in Readline
1885 a. There is now an option for `iterative' yank-last-arg handline, so a user
1886 can keep entering `M-.', yanking the last argument of successive history
1889 b. New variable, `print-completions-horizontally', which causes completion
1890 matches to be displayed across the screen (like `ls -x') rather than up
1891 and down the screen (like `ls').
1893 c. New variable, `completion-ignore-case', which causes filename completion
1894 and matching to be performed case-insensitively.
1896 d. There is a new bindable command, `magic-space', which causes history
1897 expansion to be performed on the current readline buffer and a space to
1898 be inserted into the result.
1900 e. There is a new bindable command, `menu-complete', which enables tcsh-like
1901 menu completion (successive executions of menu-complete insert a single
1902 completion match, cycling through the list of possible completions).
1904 f. There is a new bindable command, `paste-from-clipboard', for use on Win32
1905 systems, to insert the text from the Win32 clipboard into the editing
1908 g. The key sequence translation code now understands printf-style backslash
1909 escape sequences, including \NNN octal escapes. These escape sequences
1910 may be used in key sequence definitions or macro values.
1912 h. An `$include' inputrc file parser directive has been added.
1914 -------------------------------------------------------------------------------
1915 This is a terse description of the new features added to bash-2.01 since
1916 the release of bash-2.0. As always, the manual page (doc/bash.1) is the
1917 place to look for complete descriptions.
1919 1. New Features in Bash
1921 a. There is a new builtin array variable: GROUPS, the set of groups to which
1922 the user belongs. This is used by the test suite.
1924 2. New Features in Readline
1926 a. If a key sequence bound to `universal-argument' is read while reading a
1927 numeric argument started with `universal-argument', it terminates the
1928 argument but is otherwise ignored. This provides a way to insert multiple
1929 instances of a digit string, and is how GNU emacs does it.
1931 -------------------------------------------------------------------------------
1932 This is a terse description of the new features added to bash-2.0 since
1933 the release of bash-1.14.7. As always, the manual page (doc/bash.1) is
1934 the place to look for complete descriptions.
1936 1. New Features in Bash
1938 a. There is a new invocation option, -D, that dumps translatable strings
1941 b. The `long' invocation options must now be prefixed with `--'.
1943 c. New long invocation options: --dump-strings, --help, --verbose
1945 d. The `nolineediting' invocation option was renamed to `noediting'.
1947 e. The `nobraceexpansion' and `quiet' long invocation options were removed.
1949 f. The `--help' and `--version' long options now work as the GNU coding
1952 g. If invoked as `sh', bash now enters posix mode after reading the
1953 startup files, and reads and executes commands from the file named
1954 by $ENV if interactive (as POSIX.2 specifies). A login shell invoked
1955 as `sh' reads $ENV after /etc/profile and ~/.profile.
1957 h. There is a new reserved word, `time', for timing pipelines, builtin
1958 commands, and shell functions. It uses the value of the TIMEFORMAT
1959 variable as a format string describing how to print the timing
1962 i. The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the
1963 result single-quoted.
1965 j. The $"..." quoting syntax performs locale-specific translation of ...
1966 and leaves the result double-quoted.
1968 k. LINENO now works correctly in functions.
1970 l. New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS,
1971 MACHTYPE. The first three are array variables.
1973 m. The BASH_VERSION and BASH_VERSINFO variables now include the shell's
1974 `release status' (alpha[N], beta[N], release).
1976 n. Some variables have been removed: MAIL_WARNING, notify, history_control,
1977 command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
1978 nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
1979 cdable_vars. Most of them are now implemented with the new `shopt'
1980 builtin; others were already implemented by `set'.
1982 o. Bash now uses some new variables: LC_ALL, LC_MESSAGES, LC_CTYPE,
1983 LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE.
1985 p. The shell now supports integer-indexed arrays of unlimited length,
1986 with a new compound assignment syntax and changes to the appropriate
1987 builtin commands (declare/typeset, read, readonly, etc.). The array
1988 index may be an arithmetic expression.
1990 q. ${!var}: indirect variable expansion, equivalent to eval \${$var}.
1992 r. ${paramter:offset[:length]}: variable substring extraction.
1994 s. ${parameter/pattern[/[/]string]}: variable pattern substitution.
1996 t. The $[...] arithmetic expansion syntax is no longer supported, in
1999 u. Aliases can now be expanded in shell scripts with a shell option
2000 (shopt expand_aliases).
2002 v. History and history expansion can now be used in scripts with
2003 set -o history and set -H.
2005 w. All builtins now return an exit status of 2 for incorrect usage.
2007 x. Interactive shells resend SIGHUP to all running or stopped children
2008 if (and only if) they exit due to a SIGHUP.
2010 y. New prompting expansions: \a, \e, \H, \T, \@, \v, \V.
2012 z. Variable expansion in prompt strings is now controllable via a shell
2013 option (shopt promptvars).
2015 aa. Bash now defaults to using command-oriented history.
2017 bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after
2020 cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr)
2021 has been implemented.
2023 dd. Each builtin now accepts `--' to signify the end of the options, except
2024 as documented (echo, etc.).
2026 ee. All builtins use -p to display values in a re-readable format where
2027 appropriate, except as documented (echo, type, etc.).
2029 ff. The `alias' builtin has a new -p option.
2031 gg. Changes to the `bind' builtin:
2032 o has new options: -psPSVr.
2033 o the `-d' option was renamed to `-p'
2034 o the `-v' option now dumps variables; the old `-v' is now `-P'
2036 hh. The `bye' synonym for `exit' was removed.
2038 ii. The -L and -P options to `cd' and `pwd' have been documented.
2040 jj. The `cd' builtin now does spelling correction on the directory name
2041 by default. This is settable with a shell option (shopt cdspell).
2043 kk. The `declare' builtin has new options: -a, -F, -p.
2045 ll. The `dirs' builtin has new options: -c, -p, -v.
2047 mm. The new `disown' builtin removes jobs from the shell's jobs table
2048 or inhibits the resending of SIGHUP when the shell receives a
2051 nn. The `echo' builtin has a new escape character: \e.
2053 oo. The `enable' builtin can now load new builtins dynamically from shared
2054 objects on systems with the dlopen/dlsym interface. There are a number
2055 of examples in the examples/loadables directory. There are also
2056 new options: -d, -f, -s, -p.
2058 pp. The `-all' option to `enable' was removed in favor of `-a'.
2060 qq. The `exec' builtin has new options: -l, -c, -a.
2062 rr. The `hash' builtin has a new option: -p.
2064 ss. The `history' builtin has new options: -c, -p, -s.
2066 tt. The `jobs' builtin has new options: -r, -s.
2068 uu. The `kill' builtin has new options: -n signum, -l signame.
2070 vv. The `pushd' and `popd' builtins have a new option: -n.
2072 ww. The `read' builtin has new options: -p prompt, -e, -a.
2074 xx. The `readonly' builtin has a new -a option, and the -n option was removed.
2076 yy. Changes to the `set' builtin:
2077 o new options: -B, -o keyword, -o onecmd, -o history
2078 o options removed: -l, -d, -o nohash
2079 o options changed: +o, -h, -o hashall
2080 o now displays variables in a format that can be re-read as input
2082 zz. The new `shopt' builtin controls shell optional behavior previously
2083 done by setting and unsetting certain shell variables.
2085 aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2,
2086 and s1 > s2, where s1 and s2 are strings.
2088 bbb. There is a new trap, DEBUG, executed after every simple command.
2090 ccc. The `trap' builtin has a new -p option.
2092 ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems.
2094 eee. The PS1, PS2, PATH, and IFS variables may now be unset.
2096 fff. The restricted shell mode has been expanded and is now documented.
2098 ggg. Security improvements:
2099 o functions are not imported from the environment if running setuid
2101 o no startup files are sourced if running setuid or with -p
2103 hhh. The documentation has been overhauled: the texinfo manual was
2104 expanded, and HTML versions of the man page and texinfo manual
2107 iii. Changes to Posix mode:
2108 o Command lookup now finds special builtins before shell functions.
2109 o Failure of a special builtin causes a non-interactive shell to
2110 exit. Failures are defined in the POSIX.2 specification.
2111 o If the `cd' builtin finds a directory to change to using $CDPATH,
2112 the value assigned to PWD when `cd' completes does not contain
2114 o A non-interactive shell exits if a variable assignment error
2115 occurs when no command name follows the assignment statements.
2116 o A non-interactive shell exits if the interation variable in a
2117 `for' statement or the selection variable in a `select' statement
2118 is read-only or another variable assignment error occurs.
2119 o The `<>' redirection operator now opens a file for both stdin and
2120 stdout by default, not just when in posix mode.
2121 o Assignment statements preceding special builtins now persist in
2122 the shell's environment when the builtin completes.
2124 Posix mode is now completely POSIX.2-compliant (modulo bugs). When
2125 invoked as sh, bash should be completely POSIX.2-compliant.
2127 jjj. The default value of PS1 is now "\s-\v\$ ".
2129 kkk. The ksh-like ((...)) arithmetic command syntax has been implemented.
2130 This is exactly equivalent to `let "..."'.
2132 lll. Integer constants have been extended to base 64.
2134 mmm. The `ulimit' builtin now sets both hard and soft limits and reports the
2135 soft limit by default.
2137 2. New Features in Readline
2139 a. New variables: enable-keypad, input-meta (new name for meta-flag),
2140 mark-directories, visible-stats (now documented), disable-completion,
2143 b. New bindable commands: kill-region, copy-region-as-kill,
2144 copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark,
2145 character-search, character-search-backward, insert-comment,
2146 glob-expand-word, glob-list-expansions, dump-variables, dump-macros.
2148 c. New emacs keybindings: delete-horizontal-space (M-\),
2149 insert-completions (M-*), possible-completions (M-=).
2151 d. The history-search-backward and history-search-forward commands were
2152 modified to be the same as previous-line and next-line if point is at
2153 the start of the line.
2155 e. More file types are available for the visible-stats mode.
2157 3. Changes of interest in the Bash implementation
2159 a. There is a new autoconf-based configuration mechanism.
2161 b. More things have been moved from Posix mode to standard shell behavior.
2163 c. The trace output (set -x) now inserts quotes where necessary so it can
2166 d. There is a compile-time option for a system-wide interactive shell
2167 startup file (disabled by default).
2169 e. The YACC grammar is smaller and tighter, and all 66 shift-reduce
2170 conflicts are gone. Several parsing bugs have been fixed.
2172 f. Builtin option parsing has been regularized (using internal_getopt()),
2173 with the exception of `echo', `type', and `set'.
2175 g. Builtins now return standard usage messages constructed from the
2176 `short doc' used by the help builtin.
2178 h. Completion now quotes using backslashes by default, but honors
2179 user-supplied quotes.
2181 i. The GNU libc malloc is available as a configure-time option.
2183 j. There are more internationalization features; bash uses gettext if
2184 it is available. The $"..." translation syntax uses the current
2187 k. There is better reporting of job termination when the shell is not
2190 l. The shell is somewhat more efficient: it uses a little less memory and
2191 makes fewer system calls.
2193 4. Changes of interest in the Readline implementation
2195 a. There is now support for readline `callback' functions.
2197 b. There is now support for user-supplied input, redisplay, and terminal
2198 preparation functions.
2200 c. Most of the shell-specific code in readline has been generalized or
2203 d. Most of the annoying redisplay bugs have been fixed, notably the problems
2204 with incremental search and excessive redrawing when special characters
2205 appear in the prompt string.
2207 e. There are new library functions and variables available to application
2208 writers, most having to do with completion and quoting.
2210 f. The NEWLINE character (^J) is now treated as a search terminator by the
2211 incremental search functions.
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