1 This is a terse description of the new features added to bash-4.4 since
2 the release of bash-4.3. 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. There is now a settable configuration #define that will cause the shell
8 to exit if the shell is running setuid without the -p option and setuid
11 b. Command and process substitutions now turn off the `-v' option when
12 executing, as other shells seem to do.
14 c. The default value for the `checkhash' shell option may now be set at
15 compile time with a #define.
17 d. The `mapfile' builtin now has a -d option to use an arbitrary character
18 as the record delimiter, and a -t option to strip the delimiter as
21 e. The maximum number of nested recursive calls to `eval' is now settable in
22 config-top.h; the default is no limit.
24 f. The `-p' option to declare and similar builtins will display attributes for
25 named variables even when those variables have not been assigned values
26 (which are technically unset).
28 g. The maximum number of nested recursive calls to `source' is now settable
29 in config-top.h; the default is no limit.
31 h. All builtin commands recognize the `--help' option and print a usage
34 i. Bash does not allow function names containing `/' and `=' to be exported.
36 j. The `ulimit' builtin has new -k (kqueues) and -P (pseudoterminals) options.
38 k. The shell now allows `time ; othercommand' to time null commands.
40 l. There is a new `--enable-function-import' configuration option to allow
41 importing shell functions from the environment; import is enabled by
44 m. `printf -v var ""' will now set `var' to the empty string, as if `var=""'
47 n. GLOBIGNORE, the pattern substitution word expansion, and programmable
48 completion match filtering now honor the value of the `nocasematch' option.
50 o. There is a new ${parameter@spec} family of operators to transform the
53 p. Bash no longer attempts to perform compound assignment if a variable on the
54 rhs of an assignment statement argument to `declare' has the form of a
55 compound assignment (e.g., w='(word)' ; declare foo=$w); compound
56 assignments are accepted if the variable was already declared as an array,
59 q. The declare builtin no longer displays array variables using the compound
60 assignment syntax with quotes; that will generate warnings when re-used as
61 input, and isn't necessary.
63 r. Executing the rhs of && and || will no longer cause the shell to fork if
66 s. The `local' builtin takes a new argument: `-', which will cause it to save
67 and the single-letter shell options and restore their previous values at
70 t. `complete' and `compgen' have a new `-o nosort' option, which forces
71 readline to not sort the completion matches.
73 u. Bash now allows waiting for the most recent process substitution, since it
76 v. The `unset' builtin now unsets a scalar variable if it is subscripted with
77 a `0', analogous to the ${var[0]} expansion.
79 w. `set -i' is no longer valid, as in other shells.
81 x. BASH_SUBSHELL is now updated for process substitution and group commands
82 in pipelines, and is available with the same value when running any exit
85 y. Bash now checks $INSIDE_EMACS as well as $EMACS when deciding whether or
86 not bash is being run in a GNU Emacs shell window.
88 z. Bash now treats SIGINT received when running a non-builtin command in a
89 loop the way it has traditionally treated running a builtin command:
90 running any trap handler and breaking out of the loop.
92 aa. New variable: EXECIGNORE; a colon-separate list of patterns that will
93 cause matching filenames to be ignored when searching for commands.
95 bb. Aliases whose value ends in a shell metacharacter now expand in a way to
96 allow them to be `pasted' to the next token, which can potentially change
97 the meaning of a command (e.g., turning `&' into `&&').
99 cc. `make install' now installs the example loadable builtins and a set of
100 bash headers to use when developing new loadable builtins.
102 dd. `enable -f' now attempts to call functions named BUILTIN_builtin_load when
103 loading BUILTIN, and BUILTIN_builtin_unload when deleting it. This allows
104 loadable builtins to run initialization and cleanup code.
106 ee. There is a new BASH_LOADABLES_PATH variable containing a list of directories
107 where the `enable -f' command looks for shared objects containing loadable
110 ff. The `complete_fullquote' option to `shopt' changes filename completion to
111 quote all shell metacharacters in filenames and directory names.
113 gg. The `kill' builtin now has a `-L' option, equivalent to `-l', for
114 compatibility with Linux standalone versions of kill.
116 hh. BASH_COMPAT and FUNCNEST can be inherited and set from the shell's initial
119 ii. inherit_errexit: a new `shopt' option that, when set, causes command
120 substitutions to inherit the -e option. By default, those subshells disable
121 -e. It's enabled as part of turning on posix mode.
123 jj. New prompt string: PS0. Expanded and displayed by interactive shells after
124 reading a complete command but before executing it.
126 kk. Interactive shells now behave as if SIGTSTP/SIGTTIN/SIGTTOU are set to
127 SIG_DFL when the shell is started, so they are set to SIG_DFL in child
130 ll. Posix-mode shells now allow double quotes to quote the history expansion
133 mm. OLDPWD can be inherited from the environment if it names a directory.
135 nn. Shells running as root no longer inherit PS4 from the environment, closing
136 a security hole involving PS4 expansion performing command substitution.
138 oo. If executing an implicit `cd' when the `autocd' option is set, bash will
139 now invoke a function named `cd' if one exists before executing the `cd'
142 pp. Value conversions (arithmetic expansions, case modification, etc.) now
143 happen when assigning elements of an array using compound assignment.
145 qq. There is a new option settable in config-top.h that makes multiple
146 directory arguments to `cd' a fatal error.
148 rr. Bash now uses mktemp() when creating internal temporary files; it produces
149 a warning at build time on many Linux systems.
151 2. New Features in Readline
153 a. The history truncation code now uses the same error recovery mechansim as
154 the history writing code, and restores the old version of the history file
155 on error. The error recovery mechanism handles symlinked history files.
157 b. There is a new bindable variable, `enable-bracketed-paste', which enables
158 support for a terminal's bracketed paste mode.
160 c. The editing mode indicators can now be strings and are user-settable
161 (new `emacs-mode-string', `vi-cmd-mode-string' and `vi-ins-mode-string'
162 variables). Mode strings can contain invisible character sequences.
163 Setting mode strings to null strings restores the defaults.
165 d. Prompt expansion adds the mode string to the last line of a multi-line
166 prompt (one with embedded newlines).
168 e. There is a new bindable variable, `colored-completion-prefix', which, if
169 set, causes the common prefix of a set of possible completions to be
172 f. There is a new bindable command `vi-yank-pop', a vi-mode version of emacs-
175 g. The redisplay code underwent several efficiency improvements for multibyte
178 h. The insert-char function attempts to batch-insert all pending typeahead
179 that maps to self-insert, as long as it is coming from the terminal.
181 i. rl_callback_sigcleanup: a new application function that can clean up and
182 unset any state set by readline's callback mode. Intended to be used
185 j. If an incremental search string has its last character removed with DEL, the
186 resulting empty search string no longer matches the previous line.
188 k. If readline reads a history file that begins with `#' (or the value of
189 the history comment character) and has enabled history timestamps, the
190 history entries are assumed to be delimited by timestamps. This allows
191 multi-line history entries.
193 l. Readline now throws an error if it parses a key binding without a
194 terminating `:' or whitespace.
196 m. The default binding for ^W in vi mode now uses word boundaries specified
197 by Posix (vi-unix-word-rubout is bindable command name).
199 n. rl_clear_visible_line: new application-callable function; clears all
200 screen lines occupied by the current visible readline line.
202 o. rl_tty_set_echoing: application-callable function that controls whether
203 or not readline thinks it is echoing terminal output.
205 p. Handle >| and strings of digits preceding and following redirection
206 specifications as single tokens when tokenizing the line for history
209 q. Fixed a bug with displaying completions when the prefix display length
210 is greater than the length of the completions to be displayed.
212 r. The :p history modifier now applies to the entire line, so any expansion
213 specifying :p causes the line to be printed instead of expanded.
215 s. New application-callable function: rl_pending_signal(): returns the signal
216 number of any signal readline has caught but not yet handled.
218 t. New application-settable variable: rl_persistent_signal_handlers: if set
219 to a non-zero value, readline will enable the readline-6.2 signal handler
220 behavior in callback mode: handlers are installed when
221 rl_callback_handler_install is called and removed removed when a complete
224 -------------------------------------------------------------------------------
225 This is a terse description of the new features added to bash-4.3 since
226 the release of bash-4.2. As always, the manual page (doc/bash.1) is
227 the place to look for complete descriptions.
229 1. New Features in Bash
231 a. The `helptopic' completion action now maps to all the help topics, not just
234 b. The `help' builtin no longer does prefix substring matching first, so
235 `help read' does not match `readonly', but will do it if exact string
238 c. The shell can be compiled to not display a message about processes that
239 terminate due to SIGTERM.
241 d. Non-interactive shells now react to the setting of checkwinsize and set
242 LINES and COLUMNS after a foreground job exits.
244 e. There is a new shell option, `globasciiranges', which, when set to on,
245 forces globbing range comparisons to use character ordering as if they
246 were run in the C locale.
248 f. There is a new shell option, `direxpand', which makes filename completion
249 expand variables in directory names in the way bash-4.1 did.
251 g. In Posix mode, the `command' builtin does not change whether or not a
252 builtin it shadows is treated as an assignment builtin.
254 h. The `return' and `exit' builtins accept negative exit status arguments.
256 i. The word completion code checks whether or not a filename containing a
257 shell variable expands to a directory name and appends `/' to the word
258 as appropriate. The same code expands shell variables in command names
259 when performing command completion.
261 j. In Posix mode, it is now an error to attempt to define a shell function
262 with the same name as a Posix special builtin.
264 k. When compiled for strict Posix conformance, history expansion is disabled
267 l. The history expansion character (!) does not cause history expansion when
268 followed by the closing quote in a double-quoted string.
270 m. `complete' and its siblings compgen/compopt now takes a new `-o noquote'
271 option to inhibit quoting of the completions.
273 n. Setting HISTSIZE to a value less than zero causes the history list to be
274 unlimited (setting it 0 zero disables the history list).
276 o. Setting HISTFILESIZE to a value less than zero causes the history file size
277 to be unlimited (setting it to 0 causes the history file to be truncated
280 p. The `read' builtin now skips NUL bytes in the input.
282 q. There is a new `bind -X' option to print all key sequences bound to Unix
285 r. When in Posix mode, `read' is interruptible by a trapped signal. After
286 running the trap handler, read returns 128+signal and throws away any
287 partially-read input.
289 s. The command completion code skips whitespace and assignment statements
290 before looking for the command name word to be completed.
292 t. The build process has a new mechanism for constructing separate help files
293 that better reflects the current set of compilation options.
295 u. The -nt and -ot options to test now work with files with nanosecond
296 timestamp resolution.
298 v. The shell saves the command history in any shell for which history is
299 enabled and HISTFILE is set, not just interactive shells.
301 w. The shell has `nameref' variables and new -n(/+n) options to declare and
302 unset to use them, and a `test -R' option to test for them.
304 x. The shell now allows assigning, referencing, and unsetting elements of
305 indexed arrays using negative subscripts (a[-1]=2, echo ${a[-1]}) which
306 count back from the last element of the array.
308 y. The {x}<word redirection feature now allows words like {array[ind]} and
309 can use variables with special meanings to the shell (e.g., BASH_XTRACEFD).
311 z. There is a new CHILD_MAX special shell variable; its value controls the
312 number of exited child statues the shell remembers.
314 aa. There is a new configuration option (--enable-direxpand-default) that
315 causes the `direxpand' shell option to be enabled by default.
317 bb. Bash does not do anything special to ensure that the file descriptor
318 assigned to X in {x}<foo remains open after the block containing it
321 cc. The `wait' builtin has a new `-n' option to wait for the next child to
324 dd. The `printf' %(...)T format specifier now uses the current time if no
325 argument is supplied.
327 ee. There is a new variable, BASH_COMPAT, that controls the current shell
330 ff. The `popd' builtin now treats additional arguments as errors.
332 gg. The brace expansion code now treats a failed sequence expansion as a
333 simple string and will continue to expand brace terms in the remainder
336 hh. Shells started to run process substitutions now run any trap set on EXIT.
338 ii. The fc builtin now interprets -0 as the current command line.
340 jj. Completing directory names containing shell variables now adds a trailing
341 slash if the expanded result is a directory.
343 kk. `cd' has a new `-@' option to browse a file's extended attributes on
344 systems that support O_XATTR.
346 ll. The test/[/[[ `-v variable' binary operator now understands array
349 2. New Features in Readline
351 a. Readline is now more responsive to SIGHUP and other fatal signals when
352 reading input from the terminal or performing word completion but no
353 longer attempts to run any not-allowable functions from a signal handler
356 b. There are new bindable commands to search the history for the string of
357 characters between the beginning of the line and the point
358 (history-substring-search-forward, history-substring-search-backward)
360 c. Readline allows quoted strings as the values of variables when setting
361 them with `set'. As a side effect, trailing spaces and tabs are ignored
362 when setting a string variable's value.
364 d. The history library creates a backup of the history file when writing it
365 and restores the backup on a write error.
367 e. New application-settable variable: rl_filename_stat_hook: a function called
368 with a filename before using it in a call to stat(2). Bash uses it to
369 expand shell variables so things like $HOME/Downloads have a slash
372 f. New bindable function `print-last-kbd-macro', prints the most-recently-
373 defined keyboard macro in a reusable format.
375 g. New user-settable variable `colored-stats', enables use of colored text
376 to denote file types when displaying possible completions (colored analog
379 h. New user-settable variable `keyseq-timout', acts as an inter-character
380 timeout when reading input or incremental search strings.
382 i. New application-callable function: rl_clear_history. Clears the history list
383 and frees all readline-associated private data.
385 j. New user-settable variable, show-mode-in-prompt, adds a characters to the
386 beginning of the prompt indicating the current editing mode.
388 k. New application-settable variable: rl_input_available_hook; function to be
389 called when readline detects there is data available on its input file
392 l. Readline calls an application-set event hook (rl_event_hook) after it gets
393 a signal while reading input (read returns -1/EINTR but readline does not
394 handle the signal immediately) to allow the application to handle or
397 m. If the user-settable variable `history-size' is set to a value less than
398 0, the history list size is unlimited.
400 n. New application-settable variable: rl_signal_event_hook; function that is
401 called when readline is reading terminal input and read(2) is interrupted
402 by a signal. Currently not called for SIGHUP or SIGTERM.
404 o. rl_change_environment: new application-settable variable that controls
405 whether or not Readline modifies the environment (currently readline
406 modifies only LINES and COLUMNS).
408 -------------------------------------------------------------------------------
409 This is a terse description of the new features added to bash-4.2 since
410 the release of bash-4.1. As always, the manual page (doc/bash.1) is
411 the place to look for complete descriptions.
413 1. New Features in Bash
415 a. `exec -a foo' now sets $0 to `foo' in an executable shell script without a
418 b. Subshells begun to execute command substitutions or run shell functions or
419 builtins in subshells do not reset trap strings until a new trap is
420 specified. This allows $(trap) to display the caller's traps and the
421 trap strings to persist until a new trap is set.
423 c. `trap -p' will now show signals ignored at shell startup, though their
424 disposition still cannot be modified.
426 d. $'...', echo, and printf understand \uXXXX and \UXXXXXXXX escape sequences.
428 e. declare/typeset has a new `-g' option, which creates variables in the
429 global scope even when run in a shell function.
431 f. test/[/[[ have a new -v variable unary operator, which returns success if
432 `variable' has been set.
434 g. Posix parsing changes to allow `! time command' and multiple consecutive
435 instances of `!' (which toggle) and `time' (which have no cumulative
438 h. Posix change to allow `time' as a command by itself to print the elapsed
439 user, system, and real times for the shell and its children.
441 j. $((...)) is always parsed as an arithmetic expansion first, instead of as
442 a potential nested command substitution, as Posix requires.
444 k. A new FUNCNEST variable to allow the user to control the maximum shell
445 function nesting (recursive execution) level.
447 l. The mapfile builtin now supplies a third argument to the callback command:
448 the line about to be assigned to the supplied array index.
450 m. The printf builtin has a new %(fmt)T specifier, which allows time values
451 to use strftime-like formatting.
453 n. There is a new `compat41' shell option.
455 o. The cd builtin has a new Posix-mandated `-e' option.
457 p. Negative subscripts to indexed arrays, previously errors, now are treated
458 as offsets from the maximum assigned index + 1.
460 q. Negative length specifications in the ${var:offset:length} expansion,
461 previously errors, are now treated as offsets from the end of the variable.
463 r. Parsing change to allow `time -p --'.
465 s. Posix-mode parsing change to not recognize `time' as a keyword if the
466 following token begins with a `-'. This means no more Posix-mode
467 `time -p'. Posix interpretation 267.
469 t. There is a new `lastpipe' shell option that runs the last command of a
470 pipeline in the current shell context. The lastpipe option has no
471 effect if job control is enabled.
473 u. History expansion no longer expands the `$!' variable expansion.
475 v. Posix mode shells no longer exit if a variable assignment error occurs
476 with an assignment preceding a command that is not a special builtin.
478 w. Non-interactive mode shells exit if -u is enabled and an attempt is made
479 to use an unset variable with the % or # expansions, the `//', `^', or
480 `,' expansions, or the parameter length expansion.
482 x. Posix-mode shells use the argument passed to `.' as-is if a $PATH search
483 fails, effectively searching the current directory. Posix-2008 change.
485 2. New Features in Readline
487 a. The history library does not try to write the history filename in the
488 current directory if $HOME is unset. This closes a potential security
489 problem if the application does not specify a history filename.
491 b. New bindable variable `completion-display-width' to set the number of
492 columns used when displaying completions.
494 c. New bindable variable `completion-case-map' to cause case-insensitive
495 completion to treat `-' and `_' as identical.
497 d. There are new bindable vi-mode command names to avoid readline's case-
498 insensitive matching not allowing them to be bound separately.
500 e. New bindable variable `menu-complete-display-prefix' causes the menu
501 completion code to display the common prefix of the possible completions
502 before cycling through the list, instead of after.
504 -------------------------------------------------------------------------------
505 This is a terse description of the new features added to bash-4.1 since
506 the release of bash-4.0. As always, the manual page (doc/bash.1) is
507 the place to look for complete descriptions.
509 1. New Features in Bash
511 a. Here-documents within $(...) command substitutions may once more be
512 delimited by the closing right paren, instead of requiring a newline.
514 b. Bash's file status checks (executable, readable, etc.) now take file
515 system ACLs into account on file systems that support them.
517 c. Bash now passes environment variables with names that are not valid
518 shell variable names through into the environment passed to child
521 d. The `execute-unix-command' readline function now attempts to clear and
522 reuse the current line rather than move to a new one after the command
525 e. `printf -v' can now assign values to array indices.
527 f. New `complete -E' and `compopt -E' options that work on the "empty"
528 completion: completion attempted on an empty command line.
530 g. New complete/compgen/compopt -D option to define a `default' completion:
531 a completion to be invoked on command for which no completion has been
532 defined. If this function returns 124, programmable completion is
533 attempted again, allowing a user to dynamically build a set of completions
534 as completion is attempted by having the default completion function
535 install individual completion functions each time it is invoked.
537 h. When displaying associative arrays, subscripts are now quoted.
539 i. Changes to dabbrev-expand to make it more `emacs-like': no space appended
540 after matches, completions are not sorted, and most recent history entries
543 j. The [[ and (( commands are now subject to the setting of `set -e' and the
546 k. The source/. builtin now removes NUL bytes from the file before attempting
549 l. There is a new configuration option (in config-top.h) that forces bash to
550 forward all history entries to syslog.
552 m. A new variable $BASHOPTS to export shell options settable using `shopt' to
555 n. There is a new confgure option that forces the extglob option to be
558 o. New variable $BASH_XTRACEFD; when set to an integer bash will write xtrace
559 output to that file descriptor.
561 p. If the optional left-hand-side of a redirection is of the form {var}, the
562 shell assigns the file descriptor used to $var or uses $var as the file
563 descriptor to move or close, depending on the redirection operator.
565 q. The < and > operators to the [[ conditional command now do string
566 comparison according to the current locale if the compatibility level
569 r. Programmable completion now uses the completion for `b' instead of `a'
570 when completion is attempted on a line like: a $(b c.
572 s. Force extglob on temporarily when parsing the pattern argument to
573 the == and != operators to the [[ command, for compatibility.
575 t. Changed the behavior of interrupting the wait builtin when a SIGCHLD is
576 received and a trap on SIGCHLD is set to be Posix-mode only.
578 u. The read builtin has a new `-N nchars' option, which reads exactly NCHARS
579 characters, ignoring delimiters like newline.
581 v. The mapfile/readarray builtin no longer stores the commands it invokes via
582 callbacks in the history list.
584 w. There is a new `compat40' shopt option.
586 2. New Features in Readline
588 a. New bindable function: menu-complete-backward.
590 b. In the vi insertion keymap, C-n is now bound to menu-complete by default,
591 and C-p to menu-complete-backward.
593 c. When in vi command mode, repeatedly hitting ESC now does nothing, even
594 when ESC introduces a bound key sequence. This is closer to how
595 historical vi behaves.
597 d. New bindable function: skip-csi-sequence. Can be used as a default to
598 consume key sequences generated by keys like Home and End without having
601 e. New application-settable function: rl_filename_rewrite_hook. Can be used
602 to rewite or modify filenames read from the file system before they are
603 compared to the word to be completed.
605 f. New bindable variable: skip-completed-text, active when completing in the
606 middle of a word. If enabled, it means that characters in the completion
607 that match characters in the remainder of the word are "skipped" rather
608 than inserted into the line.
610 g. The pre-readline-6.0 version of menu completion is available as
611 "old-menu-complete" for users who do not like the readline-6.0 version.
613 h. New bindable variable: echo-control-characters. If enabled, and the
614 tty ECHOCTL bit is set, controls the echoing of characters corresponding
615 to keyboard-generated signals.
617 i. New bindable variable: enable-meta-key. Controls whether or not readline
618 sends the smm/rmm sequences if the terminal indicates it has a meta key
619 that enables eight-bit characters.
621 -------------------------------------------------------------------------------
622 This is a terse description of the new features added to bash-4.0 since
623 the release of bash-3.2. As always, the manual page (doc/bash.1) is
624 the place to look for complete descriptions.
626 1. New Features in Bash
628 a. When using substring expansion on the positional parameters, a starting
629 index of 0 now causes $0 to be prefixed to the list.
631 b. The `help' builtin now prints its columns with entries sorted vertically
632 rather than horizontally.
634 c. There is a new variable, $BASHPID, which always returns the process id of
637 d. There is a new `autocd' option that, when enabled, causes bash to attempt
638 to `cd' to a directory name that is supplied as the first word of a
641 e. There is a new `checkjobs' option that causes the shell to check for and
642 report any running or stopped jobs at exit.
644 f. The programmable completion code exports a new COMP_TYPE variable, set to
645 a character describing the type of completion being attempted.
647 g. The programmable completion code exports a new COMP_KEY variable, set to
648 the character that caused the completion to be invoked (e.g., TAB).
650 h. If creation of a child process fails due to insufficient resources, bash
651 will try again several times before reporting failure.
653 i. The programmable completion code now uses the same set of characters as
654 readline when breaking the command line into a list of words.
656 j. The block multiplier for the ulimit -c and -f options is now 512 when in
657 Posix mode, as Posix specifies.
659 k. Changed the behavior of the read builtin to save any partial input received
660 in the specified variable when the read builtin times out. This also
661 results in variables specified as arguments to read to be set to the empty
662 string when there is no input available. When the read builtin times out,
663 it returns an exit status greater than 128.
665 l. The shell now has the notion of a `compatibility level', controlled by
666 new variables settable by `shopt'. Setting this variable currently
667 restores the bash-3.1 behavior when processing quoted strings on the rhs
668 of the `=~' operator to the `[[' command.
670 m. The `ulimit' builtin now has new -b (socket buffer size) and -T (number
673 n. The -p option to `declare' now displays all variable values and attributes
674 (or function values and attributes if used with -f).
676 o. There is a new `compopt' builtin that allows completion functions to modify
677 completion options for existing completions or the completion currently
680 p. The `read' builtin has a new -i option which inserts text into the reply
681 buffer when using readline.
683 q. A new `-E' option to the complete builtin allows control of the default
684 behavior for completion on an empty line.
686 r. There is now limited support for completing command name words containing
689 s. Changed format of internal help documentation for all builtins to roughly
690 follow man page format.
692 t. The `help' builtin now has a new -d option, to display a short description,
693 and a -m option, to print help information in a man page-like format.
695 u. There is a new `mapfile' builtin to populate an array with lines from a
696 given file. The name `readarray' is a synonym.
698 v. If a command is not found, the shell attempts to execute a shell function
699 named `command_not_found_handle', supplying the command words as the
702 w. There is a new shell option: `globstar'. When enabled, the globbing code
703 treats `**' specially -- it matches all directories (and files within
704 them, when appropriate) recursively.
706 x. There is a new shell option: `dirspell'. When enabled, the filename
707 completion code performs spelling correction on directory names during
710 y. The `-t' option to the `read' builtin now supports fractional timeout
713 z. Brace expansion now allows zero-padding of expanded numeric values and
714 will add the proper number of zeroes to make sure all values contain the
715 same number of digits.
717 aa. There is a new bash-specific bindable readline function: `dabbrev-expand'.
718 It uses menu completion on a set of words taken from the history list.
720 bb. The command assigned to a key sequence with `bind -x' now sets two new
721 variables in the environment of the executed command: READLINE_LINE_BUFFER
722 and READLINE_POINT. The command can change the current readline line
723 and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT,
726 cc. There is a new &>> redirection operator, which appends the standard output
727 and standard error to the named file.
729 dd. The parser now understands `|&' as a synonym for `2>&1 |', which redirects
730 the standard error for a command through a pipe.
732 ee. The new `;&' case statement action list terminator causes execution to
733 continue with the action associated with the next pattern in the
734 statement rather than terminating the command.
736 ff. The new `;;&' case statement action list terminator causes the shell to
737 test the next set of patterns after completing execution of the current
738 action, rather than terminating the command.
740 gg. The shell understands a new variable: PROMPT_DIRTRIM. When set to an
741 integer value greater than zero, prompt expansion of \w and \W will
742 retain only that number of trailing pathname components and replace
743 the intervening characters with `...'.
745 hh. There are new case-modifying word expansions: uppercase (^[^]) and
746 lowercase (,[,]). They can work on either the first character or
747 array element, or globally. They accept an optional shell pattern
748 that determines which characters to modify. There is an optionally-
749 configured feature to include capitalization operators.
751 ii. The shell provides associative array variables, with the appropriate
752 support to create, delete, assign values to, and expand them.
754 jj. The `declare' builtin now has new -l (convert value to lowercase upon
755 assignment) and -u (convert value to uppercase upon assignment) options.
756 There is an optionally-configurable -c option to capitalize a value at
759 kk. There is a new `coproc' reserved word that specifies a coprocess: an
760 asynchronous command run with two pipes connected to the creating shell.
761 Coprocs can be named. The input and output file descriptors and the
762 PID of the coprocess are available to the calling shell in variables
763 with coproc-specific names.
765 ll. A value of 0 for the -t option to `read' now returns success if there is
766 input available to be read from the specified file descriptor.
768 mm. CDPATH and GLOBIGNORE are ignored when the shell is running in privileged
771 nn. New bindable readline functions shell-forward-word and shell-backward-word,
772 which move forward and backward words delimited by shell metacharacters
773 and honor shell quoting.
775 oo. New bindable readline functions shell-backward-kill-word and shell-kill-word
776 which kill words backward and forward, but use the same word boundaries
777 as shell-forward-word and shell-backward-word.
779 2. New Features in Readline
781 a. A new variable, rl_sort_completion_matches; allows applications to inhibit
782 match list sorting (but beware: some things don't work right if
783 applications do this).
785 b. A new variable, rl_completion_invoking_key; allows applications to discover
786 the key that invoked rl_complete or rl_menu_complete.
788 c. The functions rl_block_sigint and rl_release_sigint are now public and
789 available to calling applications who want to protect critical sections
792 d. The functions rl_save_state and rl_restore_state are now public and
793 available to calling applications; documented rest of readline's state
796 e. A new user-settable variable, `history-size', allows setting the maximum
797 number of entries in the history list.
799 f. There is a new implementation of menu completion, with several improvements
800 over the old; the most notable improvement is a better `completions
803 g. The menu completion code now uses the rl_menu_completion_entry_function
804 variable, allowing applications to provide their own menu completion
807 h. There is support for replacing a prefix of a pathname with a `...' when
808 displaying possible completions. This is controllable by setting the
809 `completion-prefix-display-length' variable. Matches with a common prefix
810 longer than this value have the common prefix replaced with `...'.
812 i. There is a new `revert-all-at-newline' variable. If enabled, readline will
813 undo all outstanding changes to all history lines when `accept-line' is
816 j. If the kernel supports it, readline displays special characters
817 corresponding to a keyboard-generated signal when the signal is received.
819 -------------------------------------------------------------------------------
820 This is a terse description of the new features added to bash-3.2 since
821 the release of bash-3.1. As always, the manual page (doc/bash.1) is
822 the place to look for complete descriptions.
824 1. New Features in Bash
826 a. Changed the parameter pattern replacement functions to not anchor the
827 pattern at the beginning of the string if doing global replacement - that
828 combination doesn't make any sense.
830 b. When running in `word expansion only' mode (--wordexp option), inhibit
831 process substitution.
833 c. Loadable builtins now work on MacOS X 10.[34].
835 d. Shells running in posix mode no longer set $HOME, as POSIX requires.
837 e. The code that checks for binary files being executed as shell scripts now
838 checks only for NUL rather than any non-printing character.
840 f. Quoting the string argument to the [[ command's =~ operator now forces
841 string matching, as with the other pattern-matching operators.
843 2. New Features in Readline
845 a. Calling applications can now set the keyboard timeout to 0, allowing
848 b. The value of SYS_INPUTRC (configurable at compilation time) is now used as
849 the default last-ditch startup file.
851 c. The history file reading functions now allow windows-like \r\n line
854 -------------------------------------------------------------------------------
855 This is a terse description of the new features added to bash-3.1 since
856 the release of bash-3.0. As always, the manual page (doc/bash.1) is
857 the place to look for complete descriptions.
859 1. New Features in Bash
861 a. Bash now understands LC_TIME as a special variable so that time display
862 tracks the current locale.
864 b. BASH_ARGC, BASH_ARGV, BASH_SOURCE, and BASH_LINENO are no longer created
865 as `invisible' variables and may not be unset.
867 c. In POSIX mode, if `xpg_echo' option is enabled, the `echo' builtin doesn't
868 try to interpret any options at all, as POSIX requires.
870 d. The `bg' builtin now accepts multiple arguments, as POSIX seems to specify.
872 e. Fixed vi-mode word completion and glob expansion to perform tilde
875 f. The `**' mathematic exponentiation operator is now right-associative.
877 g. The `ulimit' builtin has new options: -i (max number of pending signals),
878 -q (max size of POSIX message queues), and -x (max number of file locks).
880 h. A bare `%' once again expands to the current job when used as a job
883 i. The `+=' assignment operator (append to the value of a string or array) is
884 now supported for assignment statements and arguments to builtin commands
885 that accept assignment statements.
887 j. BASH_COMMAND now preserves its value when a DEBUG trap is executed.
889 k. The `gnu_errfmt' option is enabled automatically if the shell is running
890 in an emacs terminal window.
892 l. New configuration option: --single-help-strings. Causes long help text
893 to be written as a single string; intended to ease translation.
895 m. The COMP_WORDBREAKS variable now causes the list of word break characters
896 to be emptied when the variable is unset.
898 n. An unquoted expansion of $* when $IFS is empty now causes the positional
899 parameters to be concatenated if the expansion doesn't undergo word
902 o. Bash now inherits $_ from the environment if it appears there at startup.
904 p. New shell option: nocasematch. If non-zero, shell pattern matching ignores
905 case when used by `case' and `[[' commands.
907 q. The `printf' builtin takes a new option: -v var. That causes the output
908 to be placed into var instead of on stdout.
910 r. By default, the shell no longer reports processes dying from SIGPIPE.
912 s. Bash now sets the extern variable `environ' to the export environment it
913 creates, so C library functions that call getenv() (and can't use the
914 shell-provided replacement) get current values of environment variables.
916 t. A new configuration option, `--enable-strict-posix-default', which will
917 build bash to be POSIX conforming by default.
919 u. If compiled for strict POSIX conformance, LINES and COLUMNS may now
920 override the true terminal size.
922 2. New Features in Readline
924 a. The key sequence sent by the keypad `delete' key is now automatically
925 bound to delete-char.
927 b. A negative argument to menu-complete now cycles backward through the
930 c. A new bindable readline variable: bind-tty-special-chars. If non-zero,
931 readline will bind the terminal special characters to their readline
932 equivalents when it's called (on by default).
934 d. New bindable command: vi-rubout. Saves deleted text for possible
935 reinsertion, as with any vi-mode `text modification' command; `X' is bound
936 to this in vi command mode.
938 e. A new external application-controllable variable that allows the LINES
939 and COLUMNS environment variables to set the window size regardless of
940 what the kernel returns: rl_prefer_env_winsize
942 -------------------------------------------------------------------------------
943 This is a terse description of the new features added to bash-3.0 since
944 the release of bash-2.05b. As always, the manual page (doc/bash.1) is
945 the place to look for complete descriptions.
947 1. New Features in Bash
949 a. ANSI string expansion now implements the \x{hexdigits} escape.
951 b. There is a new loadable `strftime' builtin.
953 c. New variable, COMP_WORDBREAKS, which controls the readline completer's
954 idea of word break characters.
956 d. The `type' builtin no longer reports on aliases unless alias expansion
957 will actually be performed.
959 e. HISTCONTROL is now a colon-separated list of values, which permits
960 more extensibility and backwards compatibility.
962 f. HISTCONTROL may now include the `erasedups' option, which causes all lines
963 matching a line being added to be removed from the history list.
965 g. `configure' has a new `--enable-multibyte' argument that permits multibyte
966 character support to be disabled even on systems that support it.
968 h. New variables to support the bash debugger: BASH_ARGC, BASH_ARGV,
969 BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING,
972 i. FUNCNAME has been changed to support the debugger: it's now an array
975 j. for, case, select, arithmetic commands now keep line number information
978 k. There is a new `RETURN' trap executed when a function or sourced script
979 returns (not inherited child processes; inherited by command substitution
980 if function tracing is enabled and the debugger is active).
982 l. New invocation option: --debugger. Enables debugging and turns on new
983 `extdebug' shell option.
985 m. New `functrace' and `errtrace' options to `set -o' cause DEBUG and ERR
986 traps, respectively, to be inherited by shell functions. Equivalent to
987 `set -T' and `set -E' respectively. The `functrace' option also controls
988 whether or not the DEBUG trap is inherited by sourced scripts.
990 n. The DEBUG trap is run before binding the variable and running the action
991 list in a `for' command, binding the selection variable and running the
992 query in a `select' command, and before attempting a match in a `case'
995 o. New `--enable-debugger' option to `configure' to compile in the debugger
998 p. `declare -F' now prints out extra line number and source file information
999 if the `extdebug' option is set.
1001 q. If `extdebug' is enabled, a non-zero return value from a DEBUG trap causes
1002 the next command to be skipped, and a return value of 2 while in a
1003 function or sourced script forces a `return'.
1005 r. New `caller' builtin to provide a call stack for the bash debugger.
1007 s. The DEBUG trap is run just before the first command in a function body is
1008 executed, for the debugger.
1010 t. `for', `select', and `case' command heads are printed when `set -x' is
1013 u. There is a new {x..y} brace expansion, which is shorthand for {x.x+1,
1014 x+2,...,y}. x and y can be integers or single characters; the sequence
1015 may ascend or descend; the increment is always 1.
1017 v. New ksh93-like ${!array[@]} expansion, expands to all the keys (indices)
1020 w. New `force_fignore' shopt option; if enabled, suffixes specified by
1021 FIGNORE cause words to be ignored when performing word completion even
1022 if they're the only possibilities.
1024 x. New `gnu_errfmt' shopt option; if enabled, error messages follow the `gnu
1025 style' (filename:lineno:message) format.
1027 y. New `-o bashdefault' option to complete and compgen; if set, causes the
1028 whole set of bash completions to be performed if the compspec doesn't
1031 z. New `-o plusdirs' option to complete and compgen; if set, causes directory
1032 name completion to be performed and the results added to the rest of the
1033 possible completions.
1035 aa. `kill' is available as a builtin even when the shell is built without
1038 bb. New HISTTIMEFORMAT variable; value is a format string to pass to
1039 strftime(3). If set and not null, the `history' builtin prints out
1040 timestamp information according to the specified format when displaying
1041 history entries. If set, bash tells the history library to write out
1042 timestamp information when the history file is written.
1044 cc. The [[ ... ]] command has a new binary `=~' operator that performs
1045 extended regular expression (egrep-like) matching.
1047 dd. `configure' has a new `--enable-cond-regexp' option (enabled by default)
1048 to enable the =~ operator and regexp matching in [[ ... ]].
1050 ee. Subexpressions matched by the =~ operator are placed in the new
1051 BASH_REMATCH array variable.
1053 ff. New `failglob' option that causes an expansion error when pathname
1054 expansion fails to produce a match.
1056 gg. New `set -o pipefail' option that causes a pipeline to return a failure
1057 status if any of the processes in the pipeline fail, not just the last
1060 hh. printf builtin understands two new escape sequences: \" and \?.
1062 ii. `echo -e' understands two new escape sequences: \" and \?.
1064 jj. The GNU `gettext' package and libintl have been integrated; the shell's
1065 messages can be translated into different languages.
1067 kk. The `\W' prompt expansion now abbreviates $HOME as `~', like `\w'.
1069 ll. The error message printed when bash cannot open a shell script supplied
1070 as argument 1 now includes the name of the shell, to better identify
1071 the error as coming from bash.
1073 mm. The parameter pattern removal and substitution expansions are now much
1074 faster and more efficient when using multibyte characters.
1076 nn. The `jobs', `kill', and `wait' builtins now accept job control notation
1077 even if job control is not enabled.
1079 oo. The historical behavior of `trap' that allows a missing `action' argument
1080 to cause each specified signal's handling to be reset to its default is
1081 now only supported when `trap' is given a single non-option argument.
1083 2. New Features in Readline
1085 a. History expansion has a new `a' modifier equivalent to the `g' modifier
1086 for compatibility with the BSD csh.
1088 b. History expansion has a new `G' modifier equivalent to the BSD csh `g'
1089 modifier, which performs a substitution once per word.
1091 c. All non-incremental search operations may now undo the operation of
1092 replacing the current line with the history line.
1094 d. The text inserted by an `a' command in vi mode can be reinserted with
1097 e. New bindable variable, `show-all-if-unmodified'. If set, the readline
1098 completer will list possible completions immediately if there is more
1099 than one completion and partial completion cannot be performed.
1101 f. There is a new application-callable `free_history_entry()' function.
1103 g. History list entries now contain timestamp information; the history file
1104 functions know how to read and write timestamp information associated
1107 h. Four new key binding functions have been added:
1109 rl_bind_key_if_unbound()
1110 rl_bind_key_if_unbound_in_map()
1111 rl_bind_keyseq_if_unbound()
1112 rl_bind_keyseq_if_unbound_in_map()
1114 i. New application variable, rl_completion_quote_character, set to any
1115 quote character readline finds before it calls the application completion
1118 j. New application variable, rl_completion_suppress_quote, settable by an
1119 application completion function. If set to non-zero, readline does not
1120 attempt to append a closing quote to a completed word.
1122 k. New application variable, rl_completion_found_quote, set to a non-zero
1123 value if readline determines that the word to be completed is quoted.
1124 Set before readline calls any application completion function.
1126 l. New function hook, rl_completion_word_break_hook, called when readline
1127 needs to break a line into words when completion is attempted. Allows
1128 the word break characters to vary based on position in the line.
1130 m. New bindable command: unix-filename-rubout. Does the same thing as
1131 unix-word-rubout, but adds `/' to the set of word delimiters.
1133 n. When listing completions, directories have a `/' appended if the
1134 `mark-directories' option has been enabled.
1136 -------------------------------------------------------------------------------
1137 This is a terse description of the new features added to bash-2.05b since
1138 the release of bash-2.05a. As always, the manual page (doc/bash.1) is
1139 the place to look for complete descriptions.
1141 1. New Features in Bash
1143 a. If set, TMOUT is the default timeout for the `read' builtin.
1145 b. `type' has two new options: `-f' suppresses shell function lookup, and
1146 `-P' forces a $PATH search.
1148 c. New code to handle multibyte characters.
1150 d. `select' was changed to be more ksh-compatible, in that the menu is
1151 reprinted each time through the loop only if REPLY is set to NULL.
1152 The previous behavior is available as a compile-time option.
1154 e. `complete -d' and `complete -o dirnames' now force a slash to be
1155 appended to names which are symlinks to directories.
1157 f. There is now a bindable edit-and-execute-command readline command,
1158 like the vi-mode `v' command, bound to C-xC-e in emacs mode.
1160 g. Added support for ksh93-like [:word:] character class in pattern matching.
1162 h. The $'...' quoting construct now expands \cX to Control-X.
1164 i. A new \D{...} prompt expansion; passes the `...' to strftime and inserts
1165 the result into the expanded prompt.
1167 j. The shell now performs arithmetic in the largest integer size the
1168 machine supports (intmax_t), instead of long.
1170 k. If a numeric argument is supplied to one of the bash globbing completion
1171 functions, a `*' is appended to the word before expansion is attempted.
1173 l. The bash globbing completion functions now allow completions to be listed
1174 with double tabs or if `show-all-if-ambiguous' is set.
1176 m. New `-o nospace' option for `complete' and `compgen' builtins; suppresses
1177 readline's appending a space to the completed word.
1179 n. New `here-string' redirection operator: <<< word.
1181 o. When displaying variables, function attributes and definitions are shown
1182 separately, allowing them to be re-used as input (attempting to re-use
1183 the old output would result in syntax errors).
1185 p. There is a new configuration option `--enable-mem-scramble', controls
1186 bash malloc behavior of writing garbage characters into memory at
1187 allocation and free time.
1189 q. The `complete' and `compgen' builtins now have a new `-s/-A service'
1190 option to complete on names from /etc/services.
1192 r. `read' has a new `-u fd' option to read from a specified file descriptor.
1194 s. Fix the completion code so that expansion errors in a directory name
1195 don't cause a longjmp back to the command loop.
1197 t. Fixed word completion inside command substitution to work a little more
1200 u. The `printf' %q format specifier now uses $'...' quoting to print the
1201 argument if it contains non-printing characters.
1203 v. The `declare' and `typeset' builtins have a new `-t' option. When applied
1204 to functions, it causes the DEBUG trap to be inherited by the named
1205 function. Currently has no effect on variables.
1207 w. The DEBUG trap is now run *before* simple commands, ((...)) commands,
1208 [[...]] conditional commands, and for ((...)) loops.
1210 x. The expansion of $LINENO inside a shell function is only relative to the
1211 function start if the shell is interactive -- if the shell is running a
1212 script, $LINENO expands to the line number in the script. This is as
1213 POSIX-2001 requires.
1215 y. The bash debugger in examples/bashdb has been modified to work with the
1216 new DEBUG trap semantics, the command set has been made more gdb-like,
1217 and the changes to $LINENO make debugging functions work better. Code
1220 z. New [n]<&word- and [n]>&word- redirections from ksh93 -- move fds (dup
1223 aa. There is a new `-l' invocation option, equivalent to `--login'.
1225 bb. The `hash' builtin has a new `-l' option to list contents in a reusable
1226 format, and a `-d' option to remove a name from the hash table.
1228 cc. There is now support for placing the long help text into separate files
1229 installed into ${datadir}/bash. Not enabled by default; can be turned
1230 on with `--enable-separate-helpfiles' option to configure.
1232 dd. All builtins that take operands accept a `--' pseudo-option, except
1235 ee. The `echo' builtin now accepts \0xxx (zero to three octal digits following
1236 the `0') in addition to \xxx (one to three octal digits) for SUSv3/XPG6/
1237 POSIX.1-2001 compliance.
1240 2. New Features in Readline
1242 a. Support for key `subsequences': allows, e.g., ESC and ESC-a to both
1243 be bound to readline functions. Now the arrow keys may be used in vi
1246 b. When listing completions, and the number of lines displayed is more than
1247 the screen length, readline uses an internal pager to display the results.
1248 This is controlled by the `page-completions' variable (default on).
1250 c. New code to handle editing and displaying multibyte characters.
1252 d. The behavior introduced in bash-2.05a of deciding whether or not to
1253 append a slash to a completed name that is a symlink to a directory has
1254 been made optional, controlled by the `mark-symlinked-directories'
1255 variable (default is the 2.05a behavior).
1257 e. The `insert-comment' command now acts as a toggle if given a numeric
1258 argument: if the first characters on the line don't specify a
1259 comment, insert one; if they do, delete the comment text
1261 f. New application-settable completion variable:
1262 rl_completion_mark_symlink_dirs, allows an application's completion
1263 function to temporarily override the user's preference for appending
1264 slashes to names which are symlinks to directories.
1266 g. New function available to application completion functions:
1267 rl_completion_mode, to tell how the completion function was invoked
1268 and decide which argument to supply to rl_complete_internal (to list
1271 h. Readline now has an overwrite mode, toggled by the `overwrite-mode'
1272 bindable command, which could be bound to `Insert'.
1274 i. New application-settable completion variable:
1275 rl_completion_suppress_append, inhibits appending of
1276 rl_completion_append_character to completed words.
1278 j. New key bindings when reading an incremental search string: ^W yanks
1279 the currently-matched word out of the current line into the search
1280 string; ^Y yanks the rest of the current line into the search string,
1281 DEL or ^H deletes characters from the search string.
1283 -------------------------------------------------------------------------------
1284 This is a terse description of the new features added to bash-2.05a since
1285 the release of bash-2.05. As always, the manual page (doc/bash.1) is
1286 the place to look for complete descriptions.
1288 1. New Features in Bash
1290 a. Added support for DESTDIR installation root prefix, so you can do a
1291 `make install DESTDIR=bash-root' and do easier binary packaging.
1293 b. Added support for builtin printf "'" flag character as per latest POSIX
1296 c. Support for POSIX.2 printf(1) length specifiers `j', `t', and `z' (from
1299 d. New autoconf macro, RL_LIB_READLINE_VERSION, for use by other applications
1300 (bash doesn't use very much of what it returns).
1302 e. `set [-+]o nolog' is recognized as required by the latest POSIX drafts,
1305 f. New read-only `shopt' option: login_shell. Set to non-zero value if the
1306 shell is a login shell.
1308 g. New `\A' prompt string escape sequence; expands to time in 24 HH:MM format.
1310 h. New `-A group/-g' option to complete and compgen; does group name
1313 i. New `-t' option to `hash' to list hash values for each filename argument.
1315 j. New [-+]O invocation option to set and unset `shopt' options at startup.
1317 k. configure's `--with-installed-readline' option now takes an optional
1318 `=PATH' suffix to set the root of the tree where readline is installed
1321 l. The ksh-like `ERR' trap has been added. The `ERR' trap will be run
1322 whenever the shell would have exited if the -e option were enabled.
1323 It is not inherited by shell functions.
1325 m. `readonly', `export', and `declare' now print variables which have been
1326 given attributes but not set by assigning a value as just a command and
1327 a variable name (like `export foo') when listing, as the latest POSIX
1330 n. `bashbug' now requires that the subject be changed from the default.
1332 o. configure has a new `--enable-largefile' option, like other GNU utilities.
1334 p. `for' loops now allow empty word lists after `in', like the latest POSIX
1337 q. The builtin `ulimit' now takes two new non-numeric arguments: `hard',
1338 meaning the current hard limit, and `soft', meaning the current soft
1339 limit, in addition to `unlimited'
1341 r. `ulimit' now prints the option letter associated with a particular
1342 resource when printing more than one limit.
1344 s. `ulimit' prints `hard' or `soft' when a value is not `unlimited' but is
1345 one of RLIM_SAVED_MAX or RLIM_SAVED_CUR, respectively.
1347 t. The `printf' builtin now handles the %a and %A conversions if they're
1348 implemented by printf(3).
1350 u. The `printf' builtin now handles the %F conversion (just about like %f).
1352 v. The `printf' builtin now handles the %n conversion like printf(3). The
1353 corresponding argument is the name of a shell variable to which the
1356 2. New Features in Readline
1358 a. Added extern declaration for rl_get_termcap to readline.h, making it a
1359 public function (it was always there, just not in readline.h).
1361 b. New #defines in readline.h: RL_READLINE_VERSION, currently 0x0402,
1362 RL_VERSION_MAJOR, currently 4, and RL_VERSION_MINOR, currently 2.
1364 c. New readline variable: rl_readline_version, mirrors RL_READLINE_VERSION.
1366 d. New bindable boolean readline variable: match-hidden-files. Controls
1367 completion of files beginning with a `.' (on Unix). Enabled by default.
1369 e. The history expansion code now allows any character to terminate a
1370 `:first-' modifier, like csh.
1372 f. New bindable variable `history-preserve-point'. If set, the history
1373 code attempts to place the user at the same location on each history
1374 line retrived with previous-history or next-history.
1376 -------------------------------------------------------------------------------
1377 This is a terse description of the new features added to bash-2.05 since
1378 the release of bash-2.04. As always, the manual page (doc/bash.1) is
1379 the place to look for complete descriptions.
1381 1. New Features in Bash
1383 a. Added a new `--init-file' invocation argument as a synonym for `--rcfile',
1384 per the new GNU coding standards.
1386 b. The /dev/tcp and /dev/udp redirections now accept service names as well as
1389 c. `complete' and `compgen' now take a `-o value' option, which controls some
1390 of the aspects of that compspec. Valid values are:
1392 default - perform bash default completion if programmable
1393 completion produces no matches
1394 dirnames - perform directory name completion if programmable
1395 completion produces no matches
1396 filenames - tell readline that the compspec produces filenames,
1397 so it can do things like append slashes to
1398 directory names and suppress trailing spaces
1400 d. A new loadable builtin, realpath, which canonicalizes and expands symlinks
1401 in pathname arguments.
1403 e. When `set' is called without options, it prints function defintions in a
1404 way that allows them to be reused as input. This affects `declare' and
1405 `declare -p' as well. This only happens when the shell is not in POSIX
1406 mode, since POSIX.2 forbids this behavior.
1408 f. Bash-2.05 once again honors the current locale setting when processing
1409 ranges within pattern matching bracket expressions (e.g., [A-Z]).
1411 2. New Features in Readline
1413 a. The blink timeout for paren matching is now settable by applications,
1414 via the rl_set_paren_blink_timeout() function.
1416 b. _rl_executing_macro has been renamed to rl_executing_macro, which means
1417 it's now part of the public interface.
1419 c. Readline has a new variable, rl_readline_state, which is a bitmap that
1420 encapsulates the current state of the library; intended for use by
1421 callbacks and hook functions.
1423 d. New application-callable function rl_set_prompt(const char *prompt):
1424 expands its prompt string argument and sets rl_prompt to the result.
1426 e. New application-callable function rl_set_screen_size(int rows, int cols):
1427 public method for applications to set readline's idea of the screen
1430 f. New function, rl_get_screen_size (int *rows, int *columns), returns
1431 readline's idea of the screen dimensions.
1433 g. The timeout in rl_gather_tyi (readline keyboard input polling function)
1434 is now settable via a function (rl_set_keyboard_input_timeout()).
1436 h. Renamed the max_input_history variable to history_max_entries; the old
1437 variable is maintained for backwards compatibility.
1439 i. The list of characters that separate words for the history tokenizer is
1440 now settable with a variable: history_word_delimiters. The default
1443 -------------------------------------------------------------------------------
1444 This is a terse description of the new features added to bash-2.04 since
1445 the release of bash-2.03. As always, the manual page (doc/bash.1) is
1446 the place to look for complete descriptions.
1448 1. New Features in Bash
1450 a. The history builtin has a `-d offset' option to delete the history entry
1451 at position `offset'.
1453 b. The prompt expansion code has two new escape sequences: \j, the number of
1454 active jobs; and \l, the basename of the shell's tty device name.
1456 c. The `bind' builtin has a new `-x' option to bind key sequences to shell
1459 d. There is a new shell option, no_empty_command_completion, which, when
1460 enabled, disables command completion when TAB is typed on an empty line.
1462 e. The `help' builtin has a `-s' option to just print a builtin's usage
1465 f. There are several new arithmetic operators: id++, id-- (variable
1466 post-increment/decrement), ++id, --id (variable pre-increment/decrement),
1467 expr1 , expr2 (comma operator).
1469 g. There is a new ksh-93 style arithmetic for command:
1470 for ((expr1 ; expr2; expr3 )); do list; done
1472 h. The `read' builtin has a number of new options:
1473 -t timeout only wait timeout seconds for input
1474 -n nchars only read nchars from input instead of a full line
1475 -d delim read until delim rather than newline
1476 -s don't echo input chars as they are read
1478 i. The redirection code now handles several filenames specially:
1479 /dev/fd/N, /dev/stdin, /dev/stdout, and /dev/stderr, whether or
1480 not they are present in the file system.
1482 j. The redirection code now recognizes pathnames of the form
1483 /dev/tcp/host/port and /dev/udp/host/port, and tries to open a socket
1484 of the appropriate type to the specified port on the specified host.
1486 k. The ksh-93 ${!prefix*} expansion, which expands to the names of all
1487 shell variables with prefix PREFIX, has been implemented.
1489 l. There is a new dynamic variable, FUNCNAME, which expands to the name of
1490 a currently-executing function. Assignments to FUNCNAME have no effect.
1492 m. The GROUPS variable is no longer readonly; assignments to it are silently
1493 discarded. This means it can be unset.
1495 n. A new programmable completion facility, with two new builtin commands:
1496 complete and compgen.
1498 o. configure has a new option, `--enable-progcomp', to compile in the
1499 programmable completion features (enabled by default).
1501 p. `shopt' has a new option, `progcomp', to enable and disable programmable
1502 completion at runtime.
1504 q. Unsetting HOSTFILE now clears the list of hostnames used for completion.
1506 r. configure has a new option, `--enable-bash-malloc', replacing the old
1507 `--with-gnu-malloc' (which is still present for backwards compatibility).
1509 s. There is a new manual page describing rbash, the restricted shell.
1511 t. `bashbug' has new `--help' and `--version' options.
1513 u. `shopt' has a new `xpg_echo' option, which controls the behavior of
1514 `echo' with respect to backslash-escaped characters at runtime.
1516 v. If NON_INTERACTIVE_LOGIN_SHELLS is defined, all login shells read the
1517 startup files, even if they are not interactive.
1519 w. The LC_NUMERIC variable is now treated specially, and used to set the
1520 LC_NUMERIC locale category for number formatting, e.g., when `printf'
1521 displays floating-point numbers.
1523 2. New features in Readline
1525 a. Parentheses matching is now always compiled into readline, and enabled
1526 or disabled when the value of the `blink-matching-paren' variable is
1529 b. MS-DOS systems now use ~/_inputrc as the last-ditch inputrc filename.
1531 c. MS-DOS systems now use ~/_history as the default history file.
1533 d. history-search-{forward,backward} now leave the point at the end of the
1534 line when the string to search for is empty, like
1535 {reverse,forward}-search-history.
1537 e. history-search-{forward,backward} now leave the last history line found
1538 in the readline buffer if the second or subsequent search fails.
1540 f. New function for use by applications: rl_on_new_line_with_prompt, used
1541 when an application displays the prompt itself before calling readline().
1543 g. New variable for use by applications: rl_already_prompted. An application
1544 that displays the prompt itself before calling readline() must set this to
1547 h. A new variable, rl_gnu_readline_p, always 1. The intent is that an
1548 application can verify whether or not it is linked with the `real'
1549 readline library or some substitute.
1551 -------------------------------------------------------------------------------
1552 This is a terse description of the new features added to bash-2.03 since
1553 the release of bash-2.02. As always, the manual page (doc/bash.1) is
1554 the place to look for complete descriptions.
1556 1. New Features in Bash
1558 a. New `shopt' option, `restricted_shell', indicating whether or not the
1559 shell was started in restricted mode, for use in startup files.
1561 b. Filename generation is now performed on the words between ( and ) in
1562 array assignments (which it probably should have done all along).
1564 c. OLDPWD is now auto-exported, as POSIX.2 seems to require.
1566 d. ENV and BASH_ENV are read-only variables in a restricted shell.
1568 e. A change was made to the startup file code so that any shell begun with
1569 the `--login' option, even non-interactive shells, will source the login
1570 shell startup files.
1572 2. New Features in Readline
1574 a. Many changes to the signal handling:
1575 o Readline now catches SIGQUIT and cleans up the tty before returning;
1576 o A new variable, rl_catch_signals, is available to application writers
1577 to indicate to readline whether or not it should install its own
1578 signal handlers for SIGINT, SIGTERM, SIGQUIT, SIGALRM, SIGTSTP,
1579 SIGTTIN, and SIGTTOU;
1580 o A new variable, rl_catch_sigwinch, is available to application
1581 writers to indicate to readline whether or not it should install its
1582 own signal handler for SIGWINCH, which will chain to the calling
1583 applications's SIGWINCH handler, if one is installed;
1584 o There is a new function, rl_free_line_state, for application signal
1585 handlers to call to free up the state associated with the current
1586 line after receiving a signal;
1587 o There is a new function, rl_cleanup_after_signal, to clean up the
1588 display and terminal state after receiving a signal;
1589 o There is a new function, rl_reset_after_signal, to reinitialize the
1590 terminal and display state after an application signal handler
1591 returns and readline continues
1593 b. There is a new function, rl_resize_terminal, to reset readline's idea of
1594 the screen size after a SIGWINCH.
1596 c. New public functions: rl_save_prompt and rl_restore_prompt. These were
1597 previously private functions with a `_' prefix.
1599 d. New function hook: rl_pre_input_hook, called just before readline starts
1600 reading input, after initialization.
1602 e. New function hook: rl_display_matches_hook, called when readline would
1603 display the list of completion matches. The new function
1604 rl_display_match_list is what readline uses internally, and is available
1605 for use by application functions called via this hook.
1607 f. New bindable function, delete-char-or-list, like tcsh.
1609 g. A new variable, rl_erase_empty_line, which, if set by an application using
1610 readline, will cause readline to erase, prompt and all, lines on which the
1611 only thing typed was a newline.
1613 h. New bindable variable: `isearch-terminators'.
1615 i. New bindable function: `forward-backward-delete-char' (unbound by default).
1617 -------------------------------------------------------------------------------
1618 This is a terse description of the new features added to bash-2.02 since
1619 the release of bash-2.01.1. As always, the manual page (doc/bash.1) is
1620 the place to look for complete descriptions.
1622 1. New Features in Bash
1624 a. A new version of malloc, based on the older GNU malloc, that has many
1625 changes, is more page-based, is more conservative with memory usage,
1626 and does not `orphan' large blocks when they are freed.
1628 b. A new version of gmalloc, based on the old GLIBC malloc, with many
1629 changes and range checking included by default.
1631 c. A new implementation of fnmatch(3) that includes full POSIX.2 Basic
1632 Regular Expression matching, including character classes, collating
1633 symbols, equivalence classes, and support for case-insensitive pattern
1636 d. ksh-88 egrep-style extended pattern matching ([@+*?!](patlist)) has been
1637 implemented, controlled by a new `shopt' option, `extglob'.
1639 e. There is a new ksh-like `[[' compound command, which implements
1640 extended `test' functionality.
1642 f. There is a new `printf' builtin, implemented according to the POSIX.2
1645 g. There is a new feature for command substitution: $(< filename) now expands
1646 to the contents of `filename', with any trailing newlines removed
1647 (equivalent to $(cat filename)).
1649 h. There are new tilde prefixes which expand to directories from the
1652 i. There is a new `**' arithmetic operator to do exponentiation.
1654 j. There are new configuration options to control how bash is linked:
1655 `--enable-profiling', to allow bash to be profiled with gprof, and
1656 `--enable-static-link', to allow bash to be linked statically.
1658 k. There is a new configuration option, `--enable-cond-command', which
1659 controls whether or not the `[[' command is included. It is on by
1662 l. There is a new configuration option, `--enable-extended-glob', which
1663 controls whether or not the ksh extended globbing feature is included.
1664 It is enabled by default.
1666 m. There is a new configuration #define in config.h.top that, when enabled,
1667 will cause all login shells to source /etc/profile and one of the user-
1668 specific login shell startup files, whether or not the shell is
1671 n. There is a new invocation option, `--dump-po-strings', to dump
1672 a shell script's translatable strings ($"...") in GNU `po' format.
1674 o. There is a new `shopt' option, `nocaseglob', to enable case-insensitive
1675 pattern matching when globbing filenames and using the `case' construct.
1677 p. There is a new `shopt' option, `huponexit', which, when enabled, causes
1678 the shell to send SIGHUP to all jobs when an interactive login shell
1681 q. `bind' has a new `-u' option, which takes a readline function name as an
1682 argument and unbinds all key sequences bound to that function in a
1685 r. `disown' now has `-a' and `-r' options, to limit operation to all jobs
1686 and running jobs, respectively.
1688 s. The `shopt' `-p' option now causes output to be displayed in a reusable
1691 t. `test' has a new `-N' option, which returns true if the filename argument
1692 has been modified since it was last accessed.
1694 u. `umask' now has a `-p' option to print output in a reusable format.
1696 v. A new escape sequence, `\xNNN', has been added to the `echo -e' and $'...'
1697 translation code. It expands to the character whose ascii code is NNN
1700 w. The prompt string expansion code has a new `\r' escape sequence.
1702 x. The shell may now be cross-compiled for the CYGWIN32 environment on
1705 2. New Features in Readline
1707 a. There is now an option for `iterative' yank-last-arg handline, so a user
1708 can keep entering `M-.', yanking the last argument of successive history
1711 b. New variable, `print-completions-horizontally', which causes completion
1712 matches to be displayed across the screen (like `ls -x') rather than up
1713 and down the screen (like `ls').
1715 c. New variable, `completion-ignore-case', which causes filename completion
1716 and matching to be performed case-insensitively.
1718 d. There is a new bindable command, `magic-space', which causes history
1719 expansion to be performed on the current readline buffer and a space to
1720 be inserted into the result.
1722 e. There is a new bindable command, `menu-complete', which enables tcsh-like
1723 menu completion (successive executions of menu-complete insert a single
1724 completion match, cycling through the list of possible completions).
1726 f. There is a new bindable command, `paste-from-clipboard', for use on Win32
1727 systems, to insert the text from the Win32 clipboard into the editing
1730 g. The key sequence translation code now understands printf-style backslash
1731 escape sequences, including \NNN octal escapes. These escape sequences
1732 may be used in key sequence definitions or macro values.
1734 h. An `$include' inputrc file parser directive has been added.
1736 -------------------------------------------------------------------------------
1737 This is a terse description of the new features added to bash-2.01 since
1738 the release of bash-2.0. As always, the manual page (doc/bash.1) is the
1739 place to look for complete descriptions.
1741 1. New Features in Bash
1743 a. There is a new builtin array variable: GROUPS, the set of groups to which
1744 the user belongs. This is used by the test suite.
1746 2. New Features in Readline
1748 a. If a key sequence bound to `universal-argument' is read while reading a
1749 numeric argument started with `universal-argument', it terminates the
1750 argument but is otherwise ignored. This provides a way to insert multiple
1751 instances of a digit string, and is how GNU emacs does it.
1753 -------------------------------------------------------------------------------
1754 This is a terse description of the new features added to bash-2.0 since
1755 the release of bash-1.14.7. As always, the manual page (doc/bash.1) is
1756 the place to look for complete descriptions.
1758 1. New Features in Bash
1760 a. There is a new invocation option, -D, that dumps translatable strings
1763 b. The `long' invocation options must now be prefixed with `--'.
1765 c. New long invocation options: --dump-strings, --help, --verbose
1767 d. The `nolineediting' invocation option was renamed to `noediting'.
1769 e. The `nobraceexpansion' and `quiet' long invocation options were removed.
1771 f. The `--help' and `--version' long options now work as the GNU coding
1774 g. If invoked as `sh', bash now enters posix mode after reading the
1775 startup files, and reads and executes commands from the file named
1776 by $ENV if interactive (as POSIX.2 specifies). A login shell invoked
1777 as `sh' reads $ENV after /etc/profile and ~/.profile.
1779 h. There is a new reserved word, `time', for timing pipelines, builtin
1780 commands, and shell functions. It uses the value of the TIMEFORMAT
1781 variable as a format string describing how to print the timing
1784 i. The $'...' quoting syntax expands ANSI-C escapes in ... and leaves the
1785 result single-quoted.
1787 j. The $"..." quoting syntax performs locale-specific translation of ...
1788 and leaves the result double-quoted.
1790 k. LINENO now works correctly in functions.
1792 l. New variables: DIRSTACK, PIPESTATUS, BASH_VERSINFO, HOSTNAME, SHELLOPTS,
1793 MACHTYPE. The first three are array variables.
1795 m. The BASH_VERSION and BASH_VERSINFO variables now include the shell's
1796 `release status' (alpha[N], beta[N], release).
1798 n. Some variables have been removed: MAIL_WARNING, notify, history_control,
1799 command_oriented_history, glob_dot_filenames, allow_null_glob_expansion,
1800 nolinks, hostname_completion_file, noclobber, no_exit_on_failed_exec, and
1801 cdable_vars. Most of them are now implemented with the new `shopt'
1802 builtin; others were already implemented by `set'.
1804 o. Bash now uses some new variables: LC_ALL, LC_MESSAGES, LC_CTYPE,
1805 LC_COLLATE, LANG, GLOBIGNORE, HISTIGNORE.
1807 p. The shell now supports integer-indexed arrays of unlimited length,
1808 with a new compound assignment syntax and changes to the appropriate
1809 builtin commands (declare/typeset, read, readonly, etc.). The array
1810 index may be an arithmetic expression.
1812 q. ${!var}: indirect variable expansion, equivalent to eval \${$var}.
1814 r. ${paramter:offset[:length]}: variable substring extraction.
1816 s. ${parameter/pattern[/[/]string]}: variable pattern substitution.
1818 t. The $[...] arithmetic expansion syntax is no longer supported, in
1821 u. Aliases can now be expanded in shell scripts with a shell option
1822 (shopt expand_aliases).
1824 v. History and history expansion can now be used in scripts with
1825 set -o history and set -H.
1827 w. All builtins now return an exit status of 2 for incorrect usage.
1829 x. Interactive shells resend SIGHUP to all running or stopped children
1830 if (and only if) they exit due to a SIGHUP.
1832 y. New prompting expansions: \a, \e, \H, \T, \@, \v, \V.
1834 z. Variable expansion in prompt strings is now controllable via a shell
1835 option (shopt promptvars).
1837 aa. Bash now defaults to using command-oriented history.
1839 bb. The history file ($HISTFILE) is now truncated to $HISTFILESIZE after
1842 cc. The POSIX.2 conditional arithmetic evaluation syntax (expr ? expr : expr)
1843 has been implemented.
1845 dd. Each builtin now accepts `--' to signify the end of the options, except
1846 as documented (echo, etc.).
1848 ee. All builtins use -p to display values in a re-readable format where
1849 appropriate, except as documented (echo, type, etc.).
1851 ff. The `alias' builtin has a new -p option.
1853 gg. Changes to the `bind' builtin:
1854 o has new options: -psPSVr.
1855 o the `-d' option was renamed to `-p'
1856 o the `-v' option now dumps variables; the old `-v' is now `-P'
1858 hh. The `bye' synonym for `exit' was removed.
1860 ii. The -L and -P options to `cd' and `pwd' have been documented.
1862 jj. The `cd' builtin now does spelling correction on the directory name
1863 by default. This is settable with a shell option (shopt cdspell).
1865 kk. The `declare' builtin has new options: -a, -F, -p.
1867 ll. The `dirs' builtin has new options: -c, -p, -v.
1869 mm. The new `disown' builtin removes jobs from the shell's jobs table
1870 or inhibits the resending of SIGHUP when the shell receives a
1873 nn. The `echo' builtin has a new escape character: \e.
1875 oo. The `enable' builtin can now load new builtins dynamically from shared
1876 objects on systems with the dlopen/dlsym interface. There are a number
1877 of examples in the examples/loadables directory. There are also
1878 new options: -d, -f, -s, -p.
1880 pp. The `-all' option to `enable' was removed in favor of `-a'.
1882 qq. The `exec' builtin has new options: -l, -c, -a.
1884 rr. The `hash' builtin has a new option: -p.
1886 ss. The `history' builtin has new options: -c, -p, -s.
1888 tt. The `jobs' builtin has new options: -r, -s.
1890 uu. The `kill' builtin has new options: -n signum, -l signame.
1892 vv. The `pushd' and `popd' builtins have a new option: -n.
1894 ww. The `read' builtin has new options: -p prompt, -e, -a.
1896 xx. The `readonly' builtin has a new -a option, and the -n option was removed.
1898 yy. Changes to the `set' builtin:
1899 o new options: -B, -o keyword, -o onecmd, -o history
1900 o options removed: -l, -d, -o nohash
1901 o options changed: +o, -h, -o hashall
1902 o now displays variables in a format that can be re-read as input
1904 zz. The new `shopt' builtin controls shell optional behavior previously
1905 done by setting and unsetting certain shell variables.
1907 aaa. The `test' builtin has new operators: -o option, s1 == s2, s1 < s2,
1908 and s1 > s2, where s1 and s2 are strings.
1910 bbb. There is a new trap, DEBUG, executed after every simple command.
1912 ccc. The `trap' builtin has a new -p option.
1914 ddd. The `ulimit' builtin has a new -l option on 4.4BSD-based systems.
1916 eee. The PS1, PS2, PATH, and IFS variables may now be unset.
1918 fff. The restricted shell mode has been expanded and is now documented.
1920 ggg. Security improvements:
1921 o functions are not imported from the environment if running setuid
1923 o no startup files are sourced if running setuid or with -p
1925 hhh. The documentation has been overhauled: the texinfo manual was
1926 expanded, and HTML versions of the man page and texinfo manual
1929 iii. Changes to Posix mode:
1930 o Command lookup now finds special builtins before shell functions.
1931 o Failure of a special builtin causes a non-interactive shell to
1932 exit. Failures are defined in the POSIX.2 specification.
1933 o If the `cd' builtin finds a directory to change to using $CDPATH,
1934 the value assigned to PWD when `cd' completes does not contain
1936 o A non-interactive shell exits if a variable assignment error
1937 occurs when no command name follows the assignment statements.
1938 o A non-interactive shell exits if the interation variable in a
1939 `for' statement or the selection variable in a `select' statement
1940 is read-only or another variable assignment error occurs.
1941 o The `<>' redirection operator now opens a file for both stdin and
1942 stdout by default, not just when in posix mode.
1943 o Assignment statements preceding special builtins now persist in
1944 the shell's environment when the builtin completes.
1946 Posix mode is now completely POSIX.2-compliant (modulo bugs). When
1947 invoked as sh, bash should be completely POSIX.2-compliant.
1949 jjj. The default value of PS1 is now "\s-\v\$ ".
1951 kkk. The ksh-like ((...)) arithmetic command syntax has been implemented.
1952 This is exactly equivalent to `let "..."'.
1954 lll. Integer constants have been extended to base 64.
1956 mmm. The `ulimit' builtin now sets both hard and soft limits and reports the
1957 soft limit by default.
1959 2. New Features in Readline
1961 a. New variables: enable-keypad, input-meta (new name for meta-flag),
1962 mark-directories, visible-stats (now documented), disable-completion,
1965 b. New bindable commands: kill-region, copy-region-as-kill,
1966 copy-backward-word, copy-forward-word, set-mark, exchange-point-and-mark,
1967 character-search, character-search-backward, insert-comment,
1968 glob-expand-word, glob-list-expansions, dump-variables, dump-macros.
1970 c. New emacs keybindings: delete-horizontal-space (M-\),
1971 insert-completions (M-*), possible-completions (M-=).
1973 d. The history-search-backward and history-search-forward commands were
1974 modified to be the same as previous-line and next-line if point is at
1975 the start of the line.
1977 e. More file types are available for the visible-stats mode.
1979 3. Changes of interest in the Bash implementation
1981 a. There is a new autoconf-based configuration mechanism.
1983 b. More things have been moved from Posix mode to standard shell behavior.
1985 c. The trace output (set -x) now inserts quotes where necessary so it can
1988 d. There is a compile-time option for a system-wide interactive shell
1989 startup file (disabled by default).
1991 e. The YACC grammar is smaller and tighter, and all 66 shift-reduce
1992 conflicts are gone. Several parsing bugs have been fixed.
1994 f. Builtin option parsing has been regularized (using internal_getopt()),
1995 with the exception of `echo', `type', and `set'.
1997 g. Builtins now return standard usage messages constructed from the
1998 `short doc' used by the help builtin.
2000 h. Completion now quotes using backslashes by default, but honors
2001 user-supplied quotes.
2003 i. The GNU libc malloc is available as a configure-time option.
2005 j. There are more internationalization features; bash uses gettext if
2006 it is available. The $"..." translation syntax uses the current
2009 k. There is better reporting of job termination when the shell is not
2012 l. The shell is somewhat more efficient: it uses a little less memory and
2013 makes fewer system calls.
2015 4. Changes of interest in the Readline implementation
2017 a. There is now support for readline `callback' functions.
2019 b. There is now support for user-supplied input, redisplay, and terminal
2020 preparation functions.
2022 c. Most of the shell-specific code in readline has been generalized or
2025 d. Most of the annoying redisplay bugs have been fixed, notably the problems
2026 with incremental search and excessive redrawing when special characters
2027 appear in the prompt string.
2029 e. There are new library functions and variables available to application
2030 writers, most having to do with completion and quoting.
2032 f. The NEWLINE character (^J) is now treated as a search terminator by the
2033 incremental search functions.
2034 -------------------------------------------------------------------------------
2036 Copying and distribution of this file, with or without modification,
2037 are permitted in any medium without royalty provided the copyright
2038 notice and this notice are preserved. This file is offered as-is,
2039 without any warranty.