+This is a terse description of the new features added to bash-4.3 since
+the release of bash-4.2. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. The `helptopic' completion action now maps to all the help topics, not just
+ the shell builtins.
+
+b. The `help' builtin no longer does prefix substring matching first, so
+ `help read' does not match `readonly', but will do it if exact string
+ matching fails.
+
+c. The shell can be compiled to not display a message about processes that
+ terminate due to SIGTERM.
+
+d. Non-interactive shells now react to the setting of checkwinsize and set
+ LINES and COLUMNS after a foreground job exits.
+
+e. There is a new shell option, `globasciiranges', which, when set to on,
+ forces globbing range comparisons to use character ordering as if they
+ were run in the C locale.
+
+f. There is a new shell option, `direxpand', which makes filename completion
+ expand variables in directory names in the way bash-4.1 did.
+
+g. In Posix mode, the `command' builtin does not change whether or not a
+ builtin it shadows is treated as an assignment builtin.
+
+h. The `return' and `exit' builtins accept negative exit status arguments.
+
+i. The word completion code checks whether or not a filename containing a
+ shell variable expands to a directory name and appends `/' to the word
+ as appropriate. The same code expands shell variables in command names
+ when performing command completion.
+
+j. In Posix mode, it is now an error to attempt to define a shell function
+ with the same name as a Posix special builtin.
+
+k. When compiled for strict Posix conformance, history expansion is disabled
+ by default.
+
+l. The history expansion character (!) does not cause history expansion when
+ followed by the closing quote in a double-quoted string.
+
+m. `complete' and its siblings compgen/compopt now takes a new `-o noquote'
+ option to inhibit quoting of the completions.
+
+n. Setting HISTSIZE to a value less than zero causes the history list to be
+ unlimited (setting it 0 zero disables the history list).
+
+o. Setting HISTFILESIZE to a value less than zero causes the history file size
+ to be unlimited (setting it to 0 causes the history file to be truncated
+ to zero size).
+
+p. The `read' builtin now skips NUL bytes in the input.
+
+q. There is a new `bind -X' option to print all key sequences bound to Unix
+ commands.
+
+r. When in Posix mode, `read' is interruptible by a trapped signal. After
+ running the trap handler, read returns 128+signal and throws away any
+ partially-read input.
+
+s. The command completion code skips whitespace and assignment statements
+ before looking for the command name word to be completed.
+
+t. The build process has a new mechanism for constructing separate help files
+ that better reflects the current set of compilation options.
+
+u. The -nt and -ot options to test now work with files with nanosecond
+ timestamp resolution.
+
+v. The shell saves the command history in any shell for which history is
+ enabled and HISTFILE is set, not just interactive shells.
+
+w. The shell has `nameref' variables and new -n(/+n) options to declare and
+ unset to use them, and a `test -R' option to test for them.
+
+x. The shell now allows assigning, referencing, and unsetting elements of
+ indexed arrays using negative subscripts (a[-1]=2, echo ${a[-1]}) which
+ count back from the last element of the array.
+
+y. The {x}<word redirection feature now allows words like {array[ind]} and
+ can use variables with special meanings to the shell (e.g., BASH_XTRACEFD).
+
+z. There is a new CHILD_MAX special shell variable; its value controls the
+ number of exited child statues the shell remembers.
+
+aa. There is a new configuration option (--enable-direxpand-default) that
+ causes the `direxpand' shell option to be enabled by default.
+
+bb. Bash does not do anything special to ensure that the file descriptor
+ assigned to X in {x}<foo remains open after the block containing it
+ completes.
+
+cc. The `wait' builtin has a new `-n' option to wait for the next child to
+ change status.
+
+dd. The `printf' %(...)T format specifier now uses the current time if no
+ argument is supplied.
+
+ee. There is a new variable, BASH_COMPAT, that controls the current shell
+ compatibility level.
+
+ff. The `popd' builtin now treats additional arguments as errors.
+
+gg. The brace expansion code now treats a failed sequence expansion as a
+ simple string and will continue to expand brace terms in the remainder
+ of the word.
+
+hh. Shells started to run process substitutions now run any trap set on EXIT.
+
+ii. The fc builtin now interprets -0 as the current command line.
+
+jj. Completing directory names containing shell variables now adds a trailing
+ slash if the expanded result is a directory.
+
+kk. `cd' has a new `-@' option to browse a file's extended attributes on
+ systems that support O_XATTR.
+
+ll. The test/[/[[ `-v variable' binary operator now understands array
+ references.
+
+2. New Features in Readline
+
+a. Readline is now more responsive to SIGHUP and other fatal signals when
+ reading input from the terminal or performing word completion but no
+ longer attempts to run any not-allowable functions from a signal handler
+ context.
+
+b. There are new bindable commands to search the history for the string of
+ characters between the beginning of the line and the point
+ (history-substring-search-forward, history-substring-search-backward)
+
+c. Readline allows quoted strings as the values of variables when setting
+ them with `set'. As a side effect, trailing spaces and tabs are ignored
+ when setting a string variable's value.
+
+d. The history library creates a backup of the history file when writing it
+ and restores the backup on a write error.
+
+e. New application-settable variable: rl_filename_stat_hook: a function called
+ with a filename before using it in a call to stat(2). Bash uses it to
+ expand shell variables so things like $HOME/Downloads have a slash
+ appended.
+
+f. New bindable function `print-last-kbd-macro', prints the most-recently-
+ defined keyboard macro in a reusable format.
+
+g. New user-settable variable `colored-stats', enables use of colored text
+ to denote file types when displaying possible completions (colored analog
+ of visible-stats).
+
+h. New user-settable variable `keyseq-timout', acts as an inter-character
+ timeout when reading input or incremental search strings.
+
+i. New application-callable function: rl_clear_history. Clears the history list
+ and frees all readline-associated private data.
+
+j. New user-settable variable, show-mode-in-prompt, adds a characters to the
+ beginning of the prompt indicating the current editing mode.
+
+k. New application-settable variable: rl_input_available_hook; function to be
+ called when readline detects there is data available on its input file
+ descriptor.
+
+l. Readline calls an application-set event hook (rl_event_hook) after it gets
+ a signal while reading input (read returns -1/EINTR but readline does not
+ handle the signal immediately) to allow the application to handle or
+ otherwise note it.
+
+m. If the user-settable variable `history-size' is set to a value less than
+ 0, the history list size is unlimited.
+
+n. New application-settable variable: rl_signal_event_hook; function that is
+ called when readline is reading terminal input and read(2) is interrupted
+ by a signal. Currently not called for SIGHUP or SIGTERM.
+
+o. rl_change_environment: new application-settable variable that controls
+ whether or not Readline modifies the environment (currently readline
+ modifies only LINES and COLUMNS).
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-4.2 since
+the release of bash-4.1. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. `exec -a foo' now sets $0 to `foo' in an executable shell script without a
+ leading #!.
+
+b. Subshells begun to execute command substitutions or run shell functions or
+ builtins in subshells do not reset trap strings until a new trap is
+ specified. This allows $(trap) to display the caller's traps and the
+ trap strings to persist until a new trap is set.
+
+c. `trap -p' will now show signals ignored at shell startup, though their
+ disposition still cannot be modified.
+
+d. $'...', echo, and printf understand \uXXXX and \UXXXXXXXX escape sequences.
+
+e. declare/typeset has a new `-g' option, which creates variables in the
+ global scope even when run in a shell function.
+
+f. test/[/[[ have a new -v variable unary operator, which returns success if
+ `variable' has been set.
+
+g. Posix parsing changes to allow `! time command' and multiple consecutive
+ instances of `!' (which toggle) and `time' (which have no cumulative
+ effect).
+
+h. Posix change to allow `time' as a command by itself to print the elapsed
+ user, system, and real times for the shell and its children.
+
+j. $((...)) is always parsed as an arithmetic expansion first, instead of as
+ a potential nested command substitution, as Posix requires.
+
+k. A new FUNCNEST variable to allow the user to control the maximum shell
+ function nesting (recursive execution) level.
+
+l. The mapfile builtin now supplies a third argument to the callback command:
+ the line about to be assigned to the supplied array index.
+
+m. The printf builtin has a new %(fmt)T specifier, which allows time values
+ to use strftime-like formatting.
+
+n. There is a new `compat41' shell option.
+
+o. The cd builtin has a new Posix-mandated `-e' option.
+
+p. Negative subscripts to indexed arrays, previously errors, now are treated
+ as offsets from the maximum assigned index + 1.
+
+q. Negative length specifications in the ${var:offset:length} expansion,
+ previously errors, are now treated as offsets from the end of the variable.
+
+r. Parsing change to allow `time -p --'.
+
+s. Posix-mode parsing change to not recognize `time' as a keyword if the
+ following token begins with a `-'. This means no more Posix-mode
+ `time -p'. Posix interpretation 267.
+
+t. There is a new `lastpipe' shell option that runs the last command of a
+ pipeline in the current shell context. The lastpipe option has no
+ effect if job control is enabled.
+
+u. History expansion no longer expands the `$!' variable expansion.
+
+v. Posix mode shells no longer exit if a variable assignment error occurs
+ with an assignment preceding a command that is not a special builtin.
+
+w. Non-interactive mode shells exit if -u is enabled and an attempt is made
+ to use an unset variable with the % or # expansions, the `//', `^', or
+ `,' expansions, or the parameter length expansion.
+
+x. Posix-mode shells use the argument passed to `.' as-is if a $PATH search
+ fails, effectively searching the current directory. Posix-2008 change.
+
+2. New Features in Readline
+
+a. The history library does not try to write the history filename in the
+ current directory if $HOME is unset. This closes a potential security
+ problem if the application does not specify a history filename.
+
+b. New bindable variable `completion-display-width' to set the number of
+ columns used when displaying completions.
+
+c. New bindable variable `completion-case-map' to cause case-insensitive
+ completion to treat `-' and `_' as identical.
+
+d. There are new bindable vi-mode command names to avoid readline's case-
+ insensitive matching not allowing them to be bound separately.
+
+e. New bindable variable `menu-complete-display-prefix' causes the menu
+ completion code to display the common prefix of the possible completions
+ before cycling through the list, instead of after.
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-4.1 since
+the release of bash-4.0. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. Here-documents within $(...) command substitutions may once more be
+ delimited by the closing right paren, instead of requiring a newline.
+
+b. Bash's file status checks (executable, readable, etc.) now take file
+ system ACLs into account on file systems that support them.
+
+c. Bash now passes environment variables with names that are not valid
+ shell variable names through into the environment passed to child
+ processes.
+
+d. The `execute-unix-command' readline function now attempts to clear and
+ reuse the current line rather than move to a new one after the command
+ executes.
+
+e. `printf -v' can now assign values to array indices.
+
+f. New `complete -E' and `compopt -E' options that work on the "empty"
+ completion: completion attempted on an empty command line.
+
+g. New complete/compgen/compopt -D option to define a `default' completion:
+ a completion to be invoked on command for which no completion has been
+ defined. If this function returns 124, programmable completion is
+ attempted again, allowing a user to dynamically build a set of completions
+ as completion is attempted by having the default completion function
+ install individual completion functions each time it is invoked.
+
+h. When displaying associative arrays, subscripts are now quoted.
+
+i. Changes to dabbrev-expand to make it more `emacs-like': no space appended
+ after matches, completions are not sorted, and most recent history entries
+ are presented first.
+
+j. The [[ and (( commands are now subject to the setting of `set -e' and the
+ ERR trap.
+
+k. The source/. builtin now removes NUL bytes from the file before attempting
+ to parse commands.
+
+l. There is a new configuration option (in config-top.h) that forces bash to
+ forward all history entries to syslog.
+
+m. A new variable $BASHOPTS to export shell options settable using `shopt' to
+ child processes.
+
+n. There is a new confgure option that forces the extglob option to be
+ enabled by default.
+
+o. New variable $BASH_XTRACEFD; when set to an integer bash will write xtrace
+ output to that file descriptor.
+
+p. If the optional left-hand-side of a redirection is of the form {var}, the
+ shell assigns the file descriptor used to $var or uses $var as the file
+ descriptor to move or close, depending on the redirection operator.
+
+q. The < and > operators to the [[ conditional command now do string
+ comparison according to the current locale if the compatibility level
+ is greater than 40.
+
+r. Programmable completion now uses the completion for `b' instead of `a'
+ when completion is attempted on a line like: a $(b c.
+
+s. Force extglob on temporarily when parsing the pattern argument to
+ the == and != operators to the [[ command, for compatibility.
+
+t. Changed the behavior of interrupting the wait builtin when a SIGCHLD is
+ received and a trap on SIGCHLD is set to be Posix-mode only.
+
+u. The read builtin has a new `-N nchars' option, which reads exactly NCHARS
+ characters, ignoring delimiters like newline.
+
+v. The mapfile/readarray builtin no longer stores the commands it invokes via
+ callbacks in the history list.
+
+w. There is a new `compat40' shopt option.
+
+2. New Features in Readline
+
+a. New bindable function: menu-complete-backward.
+
+b. In the vi insertion keymap, C-n is now bound to menu-complete by default,
+ and C-p to menu-complete-backward.
+
+c. When in vi command mode, repeatedly hitting ESC now does nothing, even
+ when ESC introduces a bound key sequence. This is closer to how
+ historical vi behaves.
+
+d. New bindable function: skip-csi-sequence. Can be used as a default to
+ consume key sequences generated by keys like Home and End without having
+ to bind all keys.
+
+e. New application-settable function: rl_filename_rewrite_hook. Can be used
+ to rewite or modify filenames read from the file system before they are
+ compared to the word to be completed.
+
+f. New bindable variable: skip-completed-text, active when completing in the
+ middle of a word. If enabled, it means that characters in the completion
+ that match characters in the remainder of the word are "skipped" rather
+ than inserted into the line.
+
+g. The pre-readline-6.0 version of menu completion is available as
+ "old-menu-complete" for users who do not like the readline-6.0 version.
+
+h. New bindable variable: echo-control-characters. If enabled, and the
+ tty ECHOCTL bit is set, controls the echoing of characters corresponding
+ to keyboard-generated signals.
+
+i. New bindable variable: enable-meta-key. Controls whether or not readline
+ sends the smm/rmm sequences if the terminal indicates it has a meta key
+ that enables eight-bit characters.
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-4.0 since
+the release of bash-3.2. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. When using substring expansion on the positional parameters, a starting
+ index of 0 now causes $0 to be prefixed to the list.
+
+b. The `help' builtin now prints its columns with entries sorted vertically
+ rather than horizontally.
+
+c. There is a new variable, $BASHPID, which always returns the process id of
+ the current shell.
+
+d. There is a new `autocd' option that, when enabled, causes bash to attempt
+ to `cd' to a directory name that is supplied as the first word of a
+ simple command.
+
+e. There is a new `checkjobs' option that causes the shell to check for and
+ report any running or stopped jobs at exit.
+
+f. The programmable completion code exports a new COMP_TYPE variable, set to
+ a character describing the type of completion being attempted.
+
+g. The programmable completion code exports a new COMP_KEY variable, set to
+ the character that caused the completion to be invoked (e.g., TAB).
+
+h. If creation of a child process fails due to insufficient resources, bash
+ will try again several times before reporting failure.
+
+i. The programmable completion code now uses the same set of characters as
+ readline when breaking the command line into a list of words.
+
+j. The block multiplier for the ulimit -c and -f options is now 512 when in
+ Posix mode, as Posix specifies.
+
+k. Changed the behavior of the read builtin to save any partial input received
+ in the specified variable when the read builtin times out. This also
+ results in variables specified as arguments to read to be set to the empty
+ string when there is no input available. When the read builtin times out,
+ it returns an exit status greater than 128.
+
+l. The shell now has the notion of a `compatibility level', controlled by
+ new variables settable by `shopt'. Setting this variable currently
+ restores the bash-3.1 behavior when processing quoted strings on the rhs
+ of the `=~' operator to the `[[' command.
+
+m. The `ulimit' builtin now has new -b (socket buffer size) and -T (number
+ of threads) options.
+
+n. The -p option to `declare' now displays all variable values and attributes
+ (or function values and attributes if used with -f).
+
+o. There is a new `compopt' builtin that allows completion functions to modify
+ completion options for existing completions or the completion currently
+ being executed.
+
+p. The `read' builtin has a new -i option which inserts text into the reply
+ buffer when using readline.
+
+q. A new `-E' option to the complete builtin allows control of the default
+ behavior for completion on an empty line.
+
+r. There is now limited support for completing command name words containing
+ globbing characters.
+
+s. Changed format of internal help documentation for all builtins to roughly
+ follow man page format.
+
+t. The `help' builtin now has a new -d option, to display a short description,
+ and a -m option, to print help information in a man page-like format.
+
+u. There is a new `mapfile' builtin to populate an array with lines from a
+ given file. The name `readarray' is a synonym.
+
+v. If a command is not found, the shell attempts to execute a shell function
+ named `command_not_found_handle', supplying the command words as the
+ function arguments.
+
+w. There is a new shell option: `globstar'. When enabled, the globbing code
+ treats `**' specially -- it matches all directories (and files within
+ them, when appropriate) recursively.
+
+x. There is a new shell option: `dirspell'. When enabled, the filename
+ completion code performs spelling correction on directory names during
+ completion.
+
+y. The `-t' option to the `read' builtin now supports fractional timeout
+ values.
+
+z. Brace expansion now allows zero-padding of expanded numeric values and
+ will add the proper number of zeroes to make sure all values contain the
+ same number of digits.
+
+aa. There is a new bash-specific bindable readline function: `dabbrev-expand'.
+ It uses menu completion on a set of words taken from the history list.
+
+bb. The command assigned to a key sequence with `bind -x' now sets two new
+ variables in the environment of the executed command: READLINE_LINE_BUFFER
+ and READLINE_POINT. The command can change the current readline line
+ and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT,
+ respectively.
+
+cc. There is a new &>> redirection operator, which appends the standard output
+ and standard error to the named file.
+
+dd. The parser now understands `|&' as a synonym for `2>&1 |', which redirects
+ the standard error for a command through a pipe.
+
+ee. The new `;&' case statement action list terminator causes execution to
+ continue with the action associated with the next pattern in the
+ statement rather than terminating the command.
+
+ff. The new `;;&' case statement action list terminator causes the shell to
+ test the next set of patterns after completing execution of the current
+ action, rather than terminating the command.
+
+gg. The shell understands a new variable: PROMPT_DIRTRIM. When set to an
+ integer value greater than zero, prompt expansion of \w and \W will
+ retain only that number of trailing pathname components and replace
+ the intervening characters with `...'.
+
+hh. There are new case-modifying word expansions: uppercase (^[^]) and
+ lowercase (,[,]). They can work on either the first character or
+ array element, or globally. They accept an optional shell pattern
+ that determines which characters to modify. There is an optionally-
+ configured feature to include capitalization operators.
+
+ii. The shell provides associative array variables, with the appropriate
+ support to create, delete, assign values to, and expand them.
+
+jj. The `declare' builtin now has new -l (convert value to lowercase upon
+ assignment) and -u (convert value to uppercase upon assignment) options.
+ There is an optionally-configurable -c option to capitalize a value at
+ assignment.
+
+kk. There is a new `coproc' reserved word that specifies a coprocess: an
+ asynchronous command run with two pipes connected to the creating shell.
+ Coprocs can be named. The input and output file descriptors and the
+ PID of the coprocess are available to the calling shell in variables
+ with coproc-specific names.
+
+ll. A value of 0 for the -t option to `read' now returns success if there is
+ input available to be read from the specified file descriptor.
+
+mm. CDPATH and GLOBIGNORE are ignored when the shell is running in privileged
+ mode.
+
+nn. New bindable readline functions shell-forward-word and shell-backward-word,
+ which move forward and backward words delimited by shell metacharacters
+ and honor shell quoting.
+
+oo. New bindable readline functions shell-backward-kill-word and shell-kill-word
+ which kill words backward and forward, but use the same word boundaries
+ as shell-forward-word and shell-backward-word.
+
+2. New Features in Readline
+
+a. A new variable, rl_sort_completion_matches; allows applications to inhibit
+ match list sorting (but beware: some things don't work right if
+ applications do this).
+
+b. A new variable, rl_completion_invoking_key; allows applications to discover
+ the key that invoked rl_complete or rl_menu_complete.
+
+c. The functions rl_block_sigint and rl_release_sigint are now public and
+ available to calling applications who want to protect critical sections
+ (like redisplay).
+
+d. The functions rl_save_state and rl_restore_state are now public and
+ available to calling applications; documented rest of readline's state
+ flag values.
+
+e. A new user-settable variable, `history-size', allows setting the maximum
+ number of entries in the history list.
+
+f. There is a new implementation of menu completion, with several improvements
+ over the old; the most notable improvement is a better `completions
+ browsing' mode.
+
+g. The menu completion code now uses the rl_menu_completion_entry_function
+ variable, allowing applications to provide their own menu completion
+ generators.
+
+h. There is support for replacing a prefix of a pathname with a `...' when
+ displaying possible completions. This is controllable by setting the
+ `completion-prefix-display-length' variable. Matches with a common prefix
+ longer than this value have the common prefix replaced with `...'.
+
+i. There is a new `revert-all-at-newline' variable. If enabled, readline will
+ undo all outstanding changes to all history lines when `accept-line' is
+ executed.
+
+j. If the kernel supports it, readline displays special characters
+ corresponding to a keyboard-generated signal when the signal is received.
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-3.2 since
+the release of bash-3.1. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. Changed the parameter pattern replacement functions to not anchor the
+ pattern at the beginning of the string if doing global replacement - that
+ combination doesn't make any sense.
+
+b. When running in `word expansion only' mode (--wordexp option), inhibit
+ process substitution.
+
+c. Loadable builtins now work on MacOS X 10.[34].
+
+d. Shells running in posix mode no longer set $HOME, as POSIX requires.
+
+e. The code that checks for binary files being executed as shell scripts now
+ checks only for NUL rather than any non-printing character.
+
+f. Quoting the string argument to the [[ command's =~ operator now forces
+ string matching, as with the other pattern-matching operators.
+
+2. New Features in Readline
+
+a. Calling applications can now set the keyboard timeout to 0, allowing
+ poll-like behavior.
+
+b. The value of SYS_INPUTRC (configurable at compilation time) is now used as
+ the default last-ditch startup file.
+
+c. The history file reading functions now allow windows-like \r\n line
+ terminators.
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-3.1 since
+the release of bash-3.0. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. Bash now understands LC_TIME as a special variable so that time display
+ tracks the current locale.
+
+b. BASH_ARGC, BASH_ARGV, BASH_SOURCE, and BASH_LINENO are no longer created
+ as `invisible' variables and may not be unset.
+
+c. In POSIX mode, if `xpg_echo' option is enabled, the `echo' builtin doesn't
+ try to interpret any options at all, as POSIX requires.
+
+d. The `bg' builtin now accepts multiple arguments, as POSIX seems to specify.
+
+e. Fixed vi-mode word completion and glob expansion to perform tilde
+ expansion.
+
+f. The `**' mathematic exponentiation operator is now right-associative.
+
+g. The `ulimit' builtin has new options: -i (max number of pending signals),
+ -q (max size of POSIX message queues), and -x (max number of file locks).
+
+h. A bare `%' once again expands to the current job when used as a job
+ specifier.
+
+i. The `+=' assignment operator (append to the value of a string or array) is
+ now supported for assignment statements and arguments to builtin commands
+ that accept assignment statements.
+
+j. BASH_COMMAND now preserves its value when a DEBUG trap is executed.
+
+k. The `gnu_errfmt' option is enabled automatically if the shell is running
+ in an emacs terminal window.
+
+l. New configuration option: --single-help-strings. Causes long help text
+ to be written as a single string; intended to ease translation.
+
+m. The COMP_WORDBREAKS variable now causes the list of word break characters
+ to be emptied when the variable is unset.
+
+n. An unquoted expansion of $* when $IFS is empty now causes the positional
+ parameters to be concatenated if the expansion doesn't undergo word
+ splitting.
+
+o. Bash now inherits $_ from the environment if it appears there at startup.
+
+p. New shell option: nocasematch. If non-zero, shell pattern matching ignores
+ case when used by `case' and `[[' commands.
+
+q. The `printf' builtin takes a new option: -v var. That causes the output
+ to be placed into var instead of on stdout.
+
+r. By default, the shell no longer reports processes dying from SIGPIPE.
+
+s. Bash now sets the extern variable `environ' to the export environment it
+ creates, so C library functions that call getenv() (and can't use the
+ shell-provided replacement) get current values of environment variables.
+
+t. A new configuration option, `--enable-strict-posix-default', which will
+ build bash to be POSIX conforming by default.
+
+u. If compiled for strict POSIX conformance, LINES and COLUMNS may now
+ override the true terminal size.
+
+2. New Features in Readline
+
+a. The key sequence sent by the keypad `delete' key is now automatically
+ bound to delete-char.
+
+b. A negative argument to menu-complete now cycles backward through the
+ completion list.
+
+c. A new bindable readline variable: bind-tty-special-chars. If non-zero,
+ readline will bind the terminal special characters to their readline
+ equivalents when it's called (on by default).
+
+d. New bindable command: vi-rubout. Saves deleted text for possible
+ reinsertion, as with any vi-mode `text modification' command; `X' is bound
+ to this in vi command mode.
+
+e. A new external application-controllable variable that allows the LINES
+ and COLUMNS environment variables to set the window size regardless of
+ what the kernel returns: rl_prefer_env_winsize
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-3.0 since
+the release of bash-2.05b. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. ANSI string expansion now implements the \x{hexdigits} escape.
+
+b. There is a new loadable `strftime' builtin.
+
+c. New variable, COMP_WORDBREAKS, which controls the readline completer's
+ idea of word break characters.
+
+d. The `type' builtin no longer reports on aliases unless alias expansion
+ will actually be performed.
+
+e. HISTCONTROL is now a colon-separated list of values, which permits
+ more extensibility and backwards compatibility.
+
+f. HISTCONTROL may now include the `erasedups' option, which causes all lines
+ matching a line being added to be removed from the history list.
+
+g. `configure' has a new `--enable-multibyte' argument that permits multibyte
+ character support to be disabled even on systems that support it.
+
+h. New variables to support the bash debugger: BASH_ARGC, BASH_ARGV,
+ BASH_SOURCE, BASH_LINENO, BASH_SUBSHELL, BASH_EXECUTION_STRING,
+ BASH_COMMAND
+
+i. FUNCNAME has been changed to support the debugger: it's now an array
+ variable.
+
+j. for, case, select, arithmetic commands now keep line number information
+ for the debugger.
+
+k. There is a new `RETURN' trap executed when a function or sourced script
+ returns (not inherited child processes; inherited by command substitution
+ if function tracing is enabled and the debugger is active).
+
+l. New invocation option: --debugger. Enables debugging and turns on new
+ `extdebug' shell option.
+
+m. New `functrace' and `errtrace' options to `set -o' cause DEBUG and ERR
+ traps, respectively, to be inherited by shell functions. Equivalent to
+ `set -T' and `set -E' respectively. The `functrace' option also controls
+ whether or not the DEBUG trap is inherited by sourced scripts.
+
+n. The DEBUG trap is run before binding the variable and running the action
+ list in a `for' command, binding the selection variable and running the
+ query in a `select' command, and before attempting a match in a `case'
+ command.
+
+o. New `--enable-debugger' option to `configure' to compile in the debugger
+ support code.
+
+p. `declare -F' now prints out extra line number and source file information
+ if the `extdebug' option is set.
+
+q. If `extdebug' is enabled, a non-zero return value from a DEBUG trap causes
+ the next command to be skipped, and a return value of 2 while in a
+ function or sourced script forces a `return'.
+
+r. New `caller' builtin to provide a call stack for the bash debugger.
+
+s. The DEBUG trap is run just before the first command in a function body is
+ executed, for the debugger.
+
+t. `for', `select', and `case' command heads are printed when `set -x' is
+ enabled.
+
+u. There is a new {x..y} brace expansion, which is shorthand for {x.x+1,
+ x+2,...,y}. x and y can be integers or single characters; the sequence
+ may ascend or descend; the increment is always 1.
+
+v. New ksh93-like ${!array[@]} expansion, expands to all the keys (indices)
+ of array.
+
+w. New `force_fignore' shopt option; if enabled, suffixes specified by
+ FIGNORE cause words to be ignored when performing word completion even
+ if they're the only possibilities.
+
+x. New `gnu_errfmt' shopt option; if enabled, error messages follow the `gnu
+ style' (filename:lineno:message) format.
+
+y. New `-o bashdefault' option to complete and compgen; if set, causes the
+ whole set of bash completions to be performed if the compspec doesn't
+ result in a match.
+
+z. New `-o plusdirs' option to complete and compgen; if set, causes directory
+ name completion to be performed and the results added to the rest of the
+ possible completions.
+
+aa. `kill' is available as a builtin even when the shell is built without
+ job control.
+
+bb. New HISTTIMEFORMAT variable; value is a format string to pass to
+ strftime(3). If set and not null, the `history' builtin prints out
+ timestamp information according to the specified format when displaying
+ history entries. If set, bash tells the history library to write out
+ timestamp information when the history file is written.
+
+cc. The [[ ... ]] command has a new binary `=~' operator that performs
+ extended regular expression (egrep-like) matching.
+
+dd. `configure' has a new `--enable-cond-regexp' option (enabled by default)
+ to enable the =~ operator and regexp matching in [[ ... ]].
+
+ee. Subexpressions matched by the =~ operator are placed in the new
+ BASH_REMATCH array variable.
+
+ff. New `failglob' option that causes an expansion error when pathname
+ expansion fails to produce a match.
+
+gg. New `set -o pipefail' option that causes a pipeline to return a failure
+ status if any of the processes in the pipeline fail, not just the last
+ one.
+
+hh. printf builtin understands two new escape sequences: \" and \?.
+
+ii. `echo -e' understands two new escape sequences: \" and \?.
+
+jj. The GNU `gettext' package and libintl have been integrated; the shell's
+ messages can be translated into different languages.
+
+kk. The `\W' prompt expansion now abbreviates $HOME as `~', like `\w'.
+
+ll. The error message printed when bash cannot open a shell script supplied
+ as argument 1 now includes the name of the shell, to better identify
+ the error as coming from bash.
+
+mm. The parameter pattern removal and substitution expansions are now much
+ faster and more efficient when using multibyte characters.
+
+nn. The `jobs', `kill', and `wait' builtins now accept job control notation
+ even if job control is not enabled.
+
+oo. The historical behavior of `trap' that allows a missing `action' argument
+ to cause each specified signal's handling to be reset to its default is
+ now only supported when `trap' is given a single non-option argument.
+
+2. New Features in Readline
+
+a. History expansion has a new `a' modifier equivalent to the `g' modifier
+ for compatibility with the BSD csh.
+
+b. History expansion has a new `G' modifier equivalent to the BSD csh `g'
+ modifier, which performs a substitution once per word.
+
+c. All non-incremental search operations may now undo the operation of
+ replacing the current line with the history line.
+
+d. The text inserted by an `a' command in vi mode can be reinserted with
+ `.'.
+
+e. New bindable variable, `show-all-if-unmodified'. If set, the readline
+ completer will list possible completions immediately if there is more
+ than one completion and partial completion cannot be performed.
+
+f. There is a new application-callable `free_history_entry()' function.
+
+g. History list entries now contain timestamp information; the history file
+ functions know how to read and write timestamp information associated
+ with each entry.
+
+h. Four new key binding functions have been added:
+
+ rl_bind_key_if_unbound()
+ rl_bind_key_if_unbound_in_map()
+ rl_bind_keyseq_if_unbound()
+ rl_bind_keyseq_if_unbound_in_map()
+
+i. New application variable, rl_completion_quote_character, set to any
+ quote character readline finds before it calls the application completion
+ function.
+
+j. New application variable, rl_completion_suppress_quote, settable by an
+ application completion function. If set to non-zero, readline does not
+ attempt to append a closing quote to a completed word.
+
+k. New application variable, rl_completion_found_quote, set to a non-zero
+ value if readline determines that the word to be completed is quoted.
+ Set before readline calls any application completion function.
+
+l. New function hook, rl_completion_word_break_hook, called when readline
+ needs to break a line into words when completion is attempted. Allows
+ the word break characters to vary based on position in the line.
+
+m. New bindable command: unix-filename-rubout. Does the same thing as
+ unix-word-rubout, but adds `/' to the set of word delimiters.
+
+n. When listing completions, directories have a `/' appended if the
+ `mark-directories' option has been enabled.
+
+-------------------------------------------------------------------------------
+This is a terse description of the new features added to bash-2.05b since
+the release of bash-2.05a. As always, the manual page (doc/bash.1) is
+the place to look for complete descriptions.
+
+1. New Features in Bash
+
+a. If set, TMOUT is the default timeout for the `read' builtin.
+
+b. `type' has two new options: `-f' suppresses shell function lookup, and
+ `-P' forces a $PATH search.
+
+c. New code to handle multibyte characters.
+
+d. `select' was changed to be more ksh-compatible, in that the menu is
+ reprinted each time through the loop only if REPLY is set to NULL.
+ The previous behavior is available as a compile-time option.
+
+e. `complete -d' and `complete -o dirnames' now force a slash to be
+ appended to names which are symlinks to directories.
+
+f. There is now a bindable edit-and-execute-command readline command,
+ like the vi-mode `v' command, bound to C-xC-e in emacs mode.
+
+g. Added support for ksh93-like [:word:] character class in pattern matching.
+
+h. The $'...' quoting construct now expands \cX to Control-X.
+
+i. A new \D{...} prompt expansion; passes the `...' to strftime and inserts
+ the result into the expanded prompt.
+
+j. The shell now performs arithmetic in the largest integer size the
+ machine supports (intmax_t), instead of long.
+
+k. If a numeric argument is supplied to one of the bash globbing completion
+ functions, a `*' is appended to the word before expansion is attempted.
+
+l. The bash globbing completion functions now allow completions to be listed
+ with double tabs or if `show-all-if-ambiguous' is set.
+
+m. New `-o nospace' option for `complete' and `compgen' builtins; suppresses
+ readline's appending a space to the completed word.
+
+n. New `here-string' redirection operator: <<< word.
+
+o. When displaying variables, function attributes and definitions are shown
+ separately, allowing them to be re-used as input (attempting to re-use
+ the old output would result in syntax errors).
+
+p. There is a new configuration option `--enable-mem-scramble', controls
+ bash malloc behavior of writing garbage characters into memory at
+ allocation and free time.
+
+q. The `complete' and `compgen' builtins now have a new `-s/-A service'
+ option to complete on names from /etc/services.
+
+r. `read' has a new `-u fd' option to read from a specified file descriptor.
+
+s. Fix the completion code so that expansion errors in a directory name
+ don't cause a longjmp back to the command loop.
+
+t. Fixed word completion inside command substitution to work a little more
+ intuitively.
+
+u. The `printf' %q format specifier now uses $'...' quoting to print the
+ argument if it contains non-printing characters.
+
+v. The `declare' and `typeset' builtins have a new `-t' option. When applied
+ to functions, it causes the DEBUG trap to be inherited by the named
+ function. Currently has no effect on variables.
+
+w. The DEBUG trap is now run *before* simple commands, ((...)) commands,
+ [[...]] conditional commands, and for ((...)) loops.
+
+x. The expansion of $LINENO inside a shell function is only relative to the
+ function start if the shell is interactive -- if the shell is running a
+ script, $LINENO expands to the line number in the script. This is as
+ POSIX-2001 requires.
+
+y. The bash debugger in examples/bashdb has been modified to work with the
+ new DEBUG trap semantics, the command set has been made more gdb-like,
+ and the changes to $LINENO make debugging functions work better. Code
+ from Gary Vaughan.
+
+z. New [n]<&word- and [n]>&word- redirections from ksh93 -- move fds (dup
+ and close).
+
+aa. There is a new `-l' invocation option, equivalent to `--login'.
+
+bb. The `hash' builtin has a new `-l' option to list contents in a reusable
+ format, and a `-d' option to remove a name from the hash table.
+
+cc. There is now support for placing the long help text into separate files
+ installed into ${datadir}/bash. Not enabled by default; can be turned
+ on with `--enable-separate-helpfiles' option to configure.
+
+dd. All builtins that take operands accept a `--' pseudo-option, except
+ `echo'.
+
+ee. The `echo' builtin now accepts \0xxx (zero to three octal digits following
+ the `0') in addition to \xxx (one to three octal digits) for SUSv3/XPG6/
+ POSIX.1-2001 compliance.
+
+
+2. New Features in Readline
+
+a. Support for key `subsequences': allows, e.g., ESC and ESC-a to both
+ be bound to readline functions. Now the arrow keys may be used in vi
+ insert mode.
+
+b. When listing completions, and the number of lines displayed is more than
+ the screen length, readline uses an internal pager to display the results.
+ This is controlled by the `page-completions' variable (default on).
+
+c. New code to handle editing and displaying multibyte characters.
+
+d. The behavior introduced in bash-2.05a of deciding whether or not to
+ append a slash to a completed name that is a symlink to a directory has
+ been made optional, controlled by the `mark-symlinked-directories'
+ variable (default is the 2.05a behavior).
+
+e. The `insert-comment' command now acts as a toggle if given a numeric
+ argument: if the first characters on the line don't specify a
+ comment, insert one; if they do, delete the comment text
+
+f. New application-settable completion variable:
+ rl_completion_mark_symlink_dirs, allows an application's completion
+ function to temporarily override the user's preference for appending
+ slashes to names which are symlinks to directories.
+
+g. New function available to application completion functions:
+ rl_completion_mode, to tell how the completion function was invoked
+ and decide which argument to supply to rl_complete_internal (to list
+ completions, etc.).
+
+h. Readline now has an overwrite mode, toggled by the `overwrite-mode'
+ bindable command, which could be bound to `Insert'.
+
+i. New application-settable completion variable:
+ rl_completion_suppress_append, inhibits appending of
+ rl_completion_append_character to completed words.
+
+j. New key bindings when reading an incremental search string: ^W yanks
+ the currently-matched word out of the current line into the search
+ string; ^Y yanks the rest of the current line into the search string,
+ DEL or ^H deletes characters from the search string.
+
+-------------------------------------------------------------------------------
This is a terse description of the new features added to bash-2.05a since
the release of bash-2.05. As always, the manual page (doc/bash.1) is
the place to look for complete descriptions.
f. The NEWLINE character (^J) is now treated as a search terminator by the
incremental search functions.
+-------------------------------------------------------------------------------
+
+Copying and distribution of this file, with or without modification,
+are permitted in any medium without royalty provided the copyright
+notice and this notice are preserved. This file is offered as-is,
+without any warranty.
projects / platform / upstream / bash.git / blobdiff