+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.
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.
+ 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
and cursor position by modifying READLINE_LINE_BUFFER and READLINE_POINT,
respectively.
-cc. There is a new >>& redirection operator, which appends the standard output
+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
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