1 This is a terse description of the new features added to bash-2.03 since
2 the release of bash-2.02. 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. New `shopt' option, `restricted_shell', indicating whether or not the
8 shell was started in restricted mode, for use in startup files.
10 b. Filename generation is now performed on the words between ( and ) in
11 array assignments (which it probably should have done all along).
13 c. OLDPWD is now auto-exported, as POSIX.2 seems to require.
15 d. ENV and BASH_ENV are read-only variables in a restricted shell.
17 e. A change was made to the startup file code so that any shell begun with
18 the `--login' option, even non-interactive shells, will source the login
21 2. New Features in Readline
23 a. Many changes to the signal handling:
24 o Readline now catches SIGQUIT and cleans up the tty before returning;
25 o A new variable, rl_catch_signals, is available to application writers
26 to indicate to readline whether or not it should install its own
27 signal handlers for SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP,
29 o A new variable, rl_catch_sigwinch, is available to application
30 writers to indicate to readline whether or not it should install its
31 own signal handler for SIGWINCH, which will chain to the calling
32 applications's SIGWINCH handler, if one is installed;
33 o There is a new function, rl_free_line_state, for application signal
34 handlers to call to free up the state associated with the current
35 line after receiving a signal;
36 o There is a new function, rl_cleanup_after_signal, to clean up the
37 display and terminal state after receiving a signal;
38 o There is a new function, rl_reset_after_signal, to reinitialize the
39 terminal and display state after an application signal handler
40 returns and readline continues
42 b. There is a new function, rl_resize_terminal, to reset readline's idea of
43 the screen size after a SIGWINCH.
45 c. New public functions: rl_save_prompt and rl_restore_prompt. These were
46 previously private functions with a `_' prefix.
48 d. New function hook: rl_pre_input_hook, called just before readline starts
49 reading input, after initialization.
51 e. New function hook: rl_display_matches_hook, called when readline would
52 display the list of completion matches. The new function
53 rl_display_match_list is what readline uses internally, and is available
54 for use by application functions called via this hook.
56 f. New bindable function, delete-char-or-list, like tcsh.
58 g. A new variable, rl_erase_empty_line, which, if set by an application using
59 readline, will cause readline to erase, prompt and all, lines on which the
60 only thing typed was a newline.
62 h. New bindable variable: `isearch-terminators'.
64 i. New bindable function: `forward-backward-delete-char' (unbound by default).
66 -------------------------------------------------------------------------------
67 This is a terse description of the new features added to bash-2.02 since
68 the release of bash-2.01.1. As always, the manual page (doc/bash.1) is
69 the place to look for complete descriptions.
71 1. New Features in Bash
73 a. A new version of malloc, based on the older GNU malloc, that has many
74 changes, is more page-based, is more conservative with memory usage,
75 and does not `orphan' large blocks when they are freed.
77 b. A new version of gmalloc, based on the old GLIBC malloc, with many
78 changes and range checking included by default.
80 c. A new implementation of fnmatch(3) that includes full POSIX.2 Basic
81 Regular Expression matching, including character classes, collating
82 symbols, equivalence classes, and support for case-insensitive pattern
85 d. ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been
86 implemented, controlled by a new `shopt' option, `extglob'.
88 e. There is a new ksh-like `[[' compound command, which implements
89 extended `test' functionality.
91 f. There is a new `printf' builtin, implemented according to the POSIX.2
94 g. There is a new feature for command substitution: $(< filename) now expands
95 to the contents of `filename', with any trailing newlines removed
96 (equivalent to $(cat filename)).
98 h. There are new tilde prefixes which expand to directories from the
101 i. There is a new `**' arithmetic operator to do exponentiation.
103 j. There are new configuration options to control how bash is linked:
104 `--enable-profiling', to allow bash to be profiled with gprof, and
105 `--enable-static-link', to allow bash to be linked statically.
107 k. There is a new configuration option, `--enable-cond-command', which
108 controls whether or not the `[[' command is included. It is on by
111 l. There is a new configuration option, `--enable-extended-glob', which
112 controls whether or not the ksh extended globbing feature is included.
113 It is enabled by default.
115 m. There is a new configuration #define in config.h.top that, when enabled,
116 will cause all login shells to source /etc/profile and one of the user-
117 specific login shell startup files, whether or not the shell is
120 n. There is a new invocation option, `--dump-po-strings', to dump
121 a shell script's translatable strings ($"...") in GNU `po' format.
123 o. There is a new `shopt' option, `nocaseglob', to enable case-insensitive
124 pattern matching when globbing filenames and using the `case' construct.
126 p. There is a new `shopt' option, `huponexit', which, when enabled, causes
127 the shell to send SIGHUP to all jobs when an interactive login shell
130 q. `bind' has a new `-u' option, which takes a readline function name as an
131 argument and unbinds all key sequences bound to that function in a
134 r. `disown' now has `-a' and `-r' options, to limit operation to all jobs
135 and running jobs, respectively.
137 s. The `shopt' `-p' option now causes output to be displayed in a reusable
140 t. `test' has a new `-N' option, which returns true if the filename argument
141 has been modified since it was last accessed.
143 u. `umask' now has a `-p' option to print output in a reusable format.
145 v. A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...'
146 translation code. It expands to the character whose ascii code is NNN
149 w. The prompt string expansion code has a new `\r' escape sequence.
151 x. The shell may now be cross-compiled for the CYGWIN32 environment on
154 2. New Features in Readline
156 a. There is now an option for `iterative' yank-last-arg handline, so a user
157 can keep entering `M-.', yanking the last argument of successive history
160 b. New variable, `print-completions-horizontally', which causes completion
161 matches to be displayed across the screen (like `ls -x') rather than up
162 and down the screen (like `ls').
164 c. New variable, `completion-ignore-case', which causes filename completion
165 and matching to be performed case-insensitively.
167 d. There is a new bindable command, `magic-space', which causes history
168 expansion to be performed on the current readline buffer and a space to
169 be inserted into the result.
171 e. There is a new bindable command, `menu-complete', which enables tcsh-like
172 menu completion (successive executions of menu-complete insert a single
173 completion match, cycling through the list of possible completions).
175 f. There is a new bindable command, `paste-from-clipboard', for use on Win32
176 systems, to insert the text from the Win32 clipboard into the editing
179 g. The key sequence translation code now understands printf-style backslash
180 escape sequences, including \NNN octal escapes. These escape sequences
181 may be used in key sequence definitions or macro values.
183 h. An `$include' inputrc file parser directive has been added.
185 -------------------------------------------------------------------------------
186 This is a terse description of the new features added to bash-2.01 since
187 the release of bash-2.0. As always, the manual page (doc/bash.1) is the
188 place to look for complete descriptions.
190 1. New Features in Bash
192 a. There is a new builtin array variable: GROUPS, the set of groups to which
193 the user belongs. This is used by the test suite.
195 2. New Features in Readline
197 a. If a key sequence bound to `universal-argument' is read while reading a
198 numeric argument started with `universal-argument', it terminates the
199 argument but is otherwise ignored. This provides a way to insert multiple
200 instances of a digit string, and is how GNU emacs does it.
202 -------------------------------------------------------------------------------
203 This is a terse description of the new features added to bash-2.0 since
204 the release of bash-1.14.7. As always, the manual page (doc/bash.1) is
205 the place to look for complete descriptions.
207 1. New Features in Bash
209 a. There is a new invocation option, -D, that dumps translatable strings
212 b. The `long' invocation options must now be prefixed with `--'.
214 c. New long invocation options: --dump-strings, --help, --verbose
216 d. The `nolineediting' invocation option was renamed to `noediting'.
218 e. The `nobraceexpansion' and `quiet' long invocation options were removed.
220 f. The `--help' and `--version' long options now work as the GNU coding
223 g. If invoked as `sh', bash now enters posix mode after reading the
224 startup files, and reads and executes commands from the file named
225 by $ENV if interactive (as POSIX.2 specifies). A login shell invoked
226 as `sh' reads $ENV after /etc/profile and ~/.profile.
228 h. There is a new reserved word, `time', for timing pipelines, builtin
229 commands, and shell functions. It uses the value of the TIMEFORMAT
230 variable as a format string describing how to print the timing
233 i. The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the
234 result single-quoted.
236 j. The $"..." quoting syntax performs locale-specific translation of ...
237 and leaves the result double-quoted.
239 k. LINENO now works correctly in functions.
241 l. New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS,
242 MACHTYPE. The first three are array variables.
244 m. The BASH_VERSION and BASH_VERSINFO variables now include the shell's
245 `release status' (alpha[N], beta[N], release).
247 n. Some variables have been removed: MAIL_WARNING, notify, history_control,
248 command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
249 nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
250 cdable_vars. Most of them are now implemented with the new `shopt'
251 builtin; others were already implemented by `set'.
253 o. Bash now uses some new variables: LC_ALL, LC_MESSAGES, LC_CTYPE,
254 LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE.
256 p. The shell now supports integer-indexed arrays of unlimited length,
257 with a new compound assignment syntax and changes to the appropriate
258 builtin commands (declare/typeset, read, readonly, etc.). The array
259 index may be an arithmetic expression.
261 q. ${!var}: indirect variable expansion, equivalent to eval \${$var}.
263 r. ${paramter:offset[:length]}: variable substring extraction.
265 s. ${parameter/pattern[/[/]string]}: variable pattern substitution.
267 t. The $[...] arithmetic expansion syntax is no longer supported, in
270 u. Aliases can now be expanded in shell scripts with a shell option
271 (shopt expand_aliases).
273 v. History and history expansion can now be used in scripts with
274 set -o history and set -H.
276 w. All builtins now return an exit status of 2 for incorrect usage.
278 x. Interactive shells resend SIGHUP to all running or stopped children
279 if (and only if) they exit due to a SIGHUP.
281 y. New prompting expansions: \a, \e, \H, \T, \@, \v, \V.
283 z. Variable expansion in prompt strings is now controllable via a shell
284 option (shopt promptvars).
286 aa. Bash now defaults to using command-oriented history.
288 bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after
291 cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr)
292 has been implemented.
294 dd. Each builtin now accepts `--' to signify the end of the options, except
295 as documented (echo, etc.).
297 ee. All builtins use -p to display values in a re-readable format where
298 appropriate, except as documented (echo, type, etc.).
300 ff. The `alias' builtin has a new -p option.
302 gg. Changes to the `bind' builtin:
303 o has new options: -psPSVr.
304 o the `-d' option was renamed to `-p'
305 o the `-v' option now dumps variables; the old `-v' is now `-P'
307 hh. The `bye' synonym for `exit' was removed.
309 ii. The -L and -P options to `cd' and `pwd' have been documented.
311 jj. The `cd' builtin now does spelling correction on the directory name
312 by default. This is settable with a shell option (shopt cdspell).
314 kk. The `declare' builtin has new options: -a, -F, -p.
316 ll. The `dirs' builtin has new options: -c, -p, -v.
318 mm. The new `disown' builtin removes jobs from the shell's jobs table
319 or inhibits the resending of SIGHUP when the shell receives a
322 nn. The `echo' builtin has a new escape character: \e.
324 oo. The `enable' builtin can now load new builtins dynamically from shared
325 objects on systems with the dlopen/dlsym interface. There are a number
326 of examples in the examples/loadables directory. There are also
327 new options: -d, -f, -s, -p.
329 pp. The `-all' option to `enable' was removed in favor of `-a'.
331 qq. The `exec' builtin has new options: -l, -c, -a.
333 rr. The `hash' builtin has a new option: -p.
335 ss. The `history' builtin has new options: -c, -p, -s.
337 tt. The `jobs' builtin has new options: -r, -s.
339 uu. The `kill' builtin has new options: -n signum, -l signame.
341 vv. The `pushd' and `popd' builtins have a new option: -n.
343 ww. The `read' builtin has new options: -p prompt, -e, -a.
345 xx. The `readonly' builtin has a new -a option, and the -n option was removed.
347 yy. Changes to the `set' builtin:
348 o new options: -B, -o keyword, -o onecmd, -o history
349 o options removed: -l, -d, -o nohash
350 o options changed: +o, -h, -o hashall
351 o now displays variables in a format that can be re-read as input
353 zz. The new `shopt' builtin controls shell optional behavior previously
354 done by setting and unsetting certain shell variables.
356 aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2,
357 and s1 > s2, where s1 and s2 are strings.
359 bbb. There is a new trap, DEBUG, executed after every simple command.
361 ccc. The `trap' builtin has a new -p option.
363 ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems.
365 eee. The PS1, PS2, PATH, and IFS variables may now be unset.
367 fff. The restricted shell mode has been expanded and is now documented.
369 ggg. Security improvements:
370 o functions are not imported from the environment if running setuid
372 o no startup files are sourced if running setuid or with -p
374 hhh. The documentation has been overhauled: the texinfo manual was
375 expanded, and HTML versions of the man page and texinfo manual
378 iii. Changes to Posix mode:
379 o Command lookup now finds special builtins before shell functions.
380 o Failure of a special builtin causes a non-interactive shell to
381 exit. Failures are defined in the POSIX.2 specification.
382 o If the `cd' builtin finds a directory to change to using $CDPATH,
383 the value assigned to PWD when `cd' completes does not contain
385 o A non-interactive shell exits if a variable assignment error
386 occurs when no command name follows the assignment statements.
387 o A non-interactive shell exits if the interation variable in a
388 `for' statement or the selection variable in a `select' statement
389 is read-only or another variable assignment error occurs.
390 o The `<>' redirection operator now opens a file for both stdin and
391 stdout by default, not just when in posix mode.
392 o Assignment statements preceding special builtins now persist in
393 the shell's environment when the builtin completes.
395 Posix mode is now completely POSIX.2-compliant (modulo bugs). When
396 invoked as sh, bash should be completely POSIX.2-compliant.
398 jjj. The default value of PS1 is now "\s-\v\$ ".
400 kkk. The ksh-like ((...)) arithmetic command syntax has been implemented.
401 This is exactly equivalent to `let "..."'.
403 lll. Integer constants have been extended to base 64.
405 mmm. The `ulimit' builtin now sets both hard and soft limits and reports the
406 soft limit by default.
408 2. New Features in Readline
410 a. New variables: enable-keypad, input-meta (new name for meta-flag),
411 mark-directories, visible-stats (now documented), disable-completion,
414 b. New bindable commands: kill-region, copy-region-as-kill,
415 copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark,
416 character-search, character-search-backward, insert-comment,
417 glob-expand-word, glob-list-expansions, dump-variables, dump-macros.
419 c. New emacs keybindings: delete-horizontal-space (M-\),
420 insert-completions (M-*), possible-completions (M-=).
422 d. The history-search-backward and history-search-forward commands were
423 modified to be the same as previous-line and next-line if point is at
424 the start of the line.
426 e. More file types are available for the visible-stats mode.
428 3. Changes of interest in the Bash implementation
430 a. There is a new autoconf-based configuration mechanism.
432 b. More things have been moved from Posix mode to standard shell behavior.
434 c. The trace output (set -x) now inserts quotes where necessary so it can
437 d. There is a compile-time option for a system-wide interactive shell
438 startup file (disabled by default).
440 e. The YACC grammar is smaller and tighter, and all 66 shift-reduce
441 conflicts are gone. Several parsing bugs have been fixed.
443 f. Builtin option parsing has been regularized (using internal_getopt()),
444 with the exception of `echo', `type', and `set'.
446 g. Builtins now return standard usage messages constructed from the
447 `short doc' used by the help builtin.
449 h. Completion now quotes using backslashes by default, but honors
450 user-supplied quotes.
452 i. The GNU libc malloc is available as a configure-time option.
454 j. There are more internationalization features; bash uses gettext if
455 it is available. The $"..." translation syntax uses the current
458 k. There is better reporting of job termination when the shell is not
461 l. The shell is somewhat more efficient: it uses a little less memory and
462 makes fewer system calls.
464 4. Changes of interest in the Readline implementation
466 a. There is now support for readline `callback' functions.
468 b. There is now support for user-supplied input, redisplay, and terminal
469 preparation functions.
471 c. Most of the shell-specific code in readline has been generalized or
474 d. Most of the annoying redisplay bugs have been fixed, notably the problems
475 with incremental search and excessive redrawing when special characters
476 appear in the prompt string.
478 e. There are new library functions and variables available to application
479 writers, most having to do with completion and quoting.
481 f. The NEWLINE character (^J) is now treated as a search terminator by the
482 incremental search functions.