source: trunk/essentials/app-shells/bash/NEWS@ 3232

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.

1.  New Features in Bash

a.  Added support for DESTDIR installation root prefix, so you can do a
    `make install DESTDIR=bash-root' and do easier binary packaging.

b.  Added support for builtin printf "'" flag character as per latest POSIX
    drafts.

c.  Support for POSIX.2 printf(1) length specifiers `j', `t', and `z' (from
    ISO C99).

d.  New autoconf macro, RL_LIB_READLINE_VERSION, for use by other applications
    (bash doesn't use very much of what it returns).

e.  `set [-+]o nolog' is recognized as required by the latest POSIX drafts,
    but ignored.

f.  New read-only `shopt' option:  login_shell.  Set to non-zero value if the
    shell is a login shell.

g.  New `\A' prompt string escape sequence; expands to time in 24 HH:MM format.

h.  New `-A group/-g' option to complete and compgen; does group name
    completion.

i.  New `-t' option to `hash' to list hash values for each filename argument.

j.  New [-+]O invocation option to set and unset `shopt' options at startup.

k.  configure's `--with-installed-readline' option now takes an optional
    `=PATH' suffix to set the root of the tree where readline is installed
    to PATH.

l.  The ksh-like `ERR' trap has been added.  The `ERR' trap will be run
    whenever the shell would have exited if the -e option were enabled.
    It is not inherited by shell functions.

m.  `readonly', `export', and `declare' now print variables which have been
    given attributes but not set by assigning a value as just a command and
    a variable name (like `export foo') when listing, as the latest POSIX
    drafts require.

n.  `bashbug' now requires that the subject be changed from the default.

o.  configure has a new `--enable-largefile' option, like other GNU utilities.

p.  `for' loops now allow empty word lists after `in', like the latest POSIX
    drafts require.

q.  The builtin `ulimit' now takes two new non-numeric arguments:  `hard',
    meaning the current hard limit, and `soft', meaning the current soft  
    limit, in addition to `unlimited'
    
r.  `ulimit' now prints the option letter associated with a particular
    resource when printing more than one limit.

s.  `ulimit' prints `hard' or `soft' when a value is not `unlimited' but is
    one of RLIM_SAVED_MAX or RLIM_SAVED_CUR, respectively.

t.  The `printf' builtin now handles the %a and %A conversions if they're
    implemented by printf(3).

u.  The `printf' builtin now handles the %F conversion (just about like %f).

v.  The `printf' builtin now handles the %n conversion like printf(3).  The
    corresponding argument is the name of a shell variable to which the
    value is assigned.

2.  New Features in Readline

a.  Added extern declaration for rl_get_termcap to readline.h, making it a
    public function (it was always there, just not in readline.h).

b.  New #defines in readline.h:  RL_READLINE_VERSION, currently 0x0402,
    RL_VERSION_MAJOR, currently 4, and RL_VERSION_MINOR, currently 2.

c.  New readline variable:  rl_readline_version, mirrors RL_READLINE_VERSION.

d.  New bindable boolean readline variable:  match-hidden-files.  Controls
    completion of files beginning with a `.' (on Unix).  Enabled by default.

e.  The history expansion code now allows any character to terminate a
    `:first-' modifier, like csh.

f.  New bindable variable `history-preserve-point'.  If set, the history
    code attempts to place the user at the same location on each history
    line retrived with previous-history or next-history.

-------------------------------------------------------------------------------
This is a terse description of the new features added to bash-2.05 since
the release of bash-2.04.  As always, the manual page (doc/bash.1) is
the place to look for complete descriptions.

1.  New Features in Bash

a.  Added a new `--init-file' invocation argument as a synonym for `--rcfile',
    per the new GNU coding standards.

b.  The /dev/tcp and /dev/udp redirections now accept service names as well as
    port numbers.

c.  `complete' and `compgen' now take a `-o value' option, which controls some
    of the aspects of that compspec.  Valid values are:

        default - perform bash default completion if programmable
                  completion produces no matches
        dirnames - perform directory name completion if programmable
                   completion produces no matches
        filenames - tell readline that the compspec produces filenames,
                    so it can do things like append slashes to
                    directory names and suppress trailing spaces

d.  A new loadable builtin, realpath, which canonicalizes and expands symlinks
    in pathname arguments.
    
e.  When `set' is called without options, it prints function defintions in a
    way that allows them to be reused as input.  This affects `declare' and 
    `declare -p' as well.  This only happens when the shell is not in POSIX
    mode, since POSIX.2 forbids this behavior.

f.  Bash-2.05 once again honors the current locale setting when processing
    ranges within pattern matching bracket expressions (e.g., [A-Z]).

2.  New Features in Readline

a.  The blink timeout for paren matching is now settable by applications,
    via the rl_set_paren_blink_timeout() function.

b.  _rl_executing_macro has been renamed to rl_executing_macro, which means
    it's now part of the public interface.

c.  Readline has a new variable, rl_readline_state, which is a bitmap that
    encapsulates the current state of the library; intended for use by
    callbacks and hook functions.

d.  New application-callable function rl_set_prompt(const char *prompt):
    expands its prompt string argument and sets rl_prompt to the result.

e.  New application-callable function rl_set_screen_size(int rows, int cols):
    public method for applications to set readline's idea of the screen
    dimensions.

f.  New function, rl_get_screen_size (int *rows, int *columns), returns
    readline's idea of the screen dimensions.

g.  The timeout in rl_gather_tyi (readline keyboard input polling function)
    is now settable via a function (rl_set_keyboard_input_timeout()).

h.  Renamed the max_input_history variable to history_max_entries; the old
    variable is maintained for backwards compatibility.

i.  The list of characters that separate words for the history tokenizer is
    now settable with a variable:  history_word_delimiters.  The default
    value is as before.

-------------------------------------------------------------------------------
This is a terse description of the new features added to bash-2.04 since
the release of bash-2.03.  As always, the manual page (doc/bash.1) is
the place to look for complete descriptions.

1.  New Features in Bash

a.  The history builtin has a `-d offset' option to delete the history entry
    at position `offset'.

b.  The prompt expansion code has two new escape sequences: \j, the number of
    active jobs; and \l, the basename of the shell's tty device name.

c.  The `bind' builtin has a new `-x' option to bind key sequences to shell   
    commands.

d.  There is a new shell option, no_empty_command_completion, which, when
    enabled, disables command completion when TAB is typed on an empty line.

e.  The `help' builtin has a `-s' option to just print a builtin's usage
    synopsis.

f.  There are several new arithmetic operators:  id++, id-- (variable
    post-increment/decrement), ++id, --id (variable pre-increment/decrement),
    expr1 , expr2 (comma operator).

g.  There is a new ksh-93 style arithmetic for command:
        for ((expr1 ; expr2; expr3 )); do list; done

h.  The `read' builtin has a number of new options:
        -t timeout      only wait timeout seconds for input
        -n nchars       only read nchars from input instead of a full line
        -d delim        read until delim rather than newline
        -s              don't echo input chars as they are read