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Diffstat (limited to 'NEWS')
| -rw-r--r-- | NEWS | 321 |
1 files changed, 321 insertions, 0 deletions
@@ -1,3 +1,318 @@ +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. @@ -1212,3 +1527,9 @@ e. There are new library functions and variables available to application 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. |