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    completion options for existing completions or the completion currently
    being executed.

o   The `read' builtin has a new -i option which inserts text into the reply
    buffer when using readline.

o   A new `-E' option to the complete builtin allows control of the default
    behavior for completion on an empty line.

o   There is now limited support for completing command name words containing
    globbing characters.

o   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.

o   There is a new `mapfile' builtin to populate an array with lines from a
    given file.

o   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.

o   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.

o   There is a new shell option: `dirspell'.  When enabled, the filename
    completion code performs spelling correction on directory names during
    completion.

o   The `-t' option to the `read' builtin now supports fractional timeout
    values.

o   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.

o   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.

o   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.

o   There is a new >>& redirection operator, which appends the standard output
    and standard error to the named file.

o   The parser now understands `|&' as a synonym for `2>&1 |', which redirects
    the standard error for a command through a pipe.

o   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.

o   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.

o   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 `...'.

o   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.

o   The shell provides associative array variables, with the appropriate
    support to create, delete, assign values to, and expand them.

o   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.

o   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.

o   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.

o   CDPATH and GLOBIGNORE are ignored when the shell is running in privileged
    mode.

o   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.

o   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.

Bash-3.2 contained the following new features:

o Bash-3.2 now checks shell scripts for NUL characters rather than non-printing
  characters when deciding whether or not a script is a binary file.

o Quoting the string argument to the [[ command's  =~ (regexp) operator now
  forces string matching, as with the other pattern-matching operators.

Bash-3.1 contained the following new features:

o Bash-3.1 may now be configured and built in a mode that enforces strict
  POSIX compliance.

o The `+=' assignment operator, which appends to the value of a string or
  array variable, has been implemented.

o It is now possible to ignore case when matching in contexts other than
  filename generation using the new `nocasematch' shell option.

Bash-3.0 contained the following new features:

o Features to support the bash debugger have been implemented, and there
  is a new `extdebug' option to turn the non-default options on

o HISTCONTROL is now a colon-separated list of options and has been
  extended with a new `erasedups' option that will result in only one
  copy of a command being kept in the history list

o Brace expansion has been extended with a new {x..y} form, producing
  sequences of digits or characters

o Timestamps are now kept with history entries, with an option to save
  and restore them from the history file; there is a new HISTTIMEFORMAT
  variable describing how to display the timestamps when listing history
  entries

o The `[[' command can now perform extended regular expression (egrep-like)
  matching, with matched subexpressions placed in the BASH_REMATCH array
  variable

o A new `pipefail' option causes a pipeline to return a failure status if
  any command in it fails

o The `jobs', `kill', and `wait' builtins now accept job control notation
  in their arguments even if job control is not enabled

o The `gettext' package and libintl have been integrated, and the shell
  messages may be translated into other languages

Bash-2.05b introduced the following new features:

o support for multibyte characters has been added to both bash and readline

o the DEBUG trap is now run *before* simple commands, ((...)) commands,
  [[...]] conditional commands, and for ((...)) loops

o the shell now performs arithmetic in the largest integer size the machine
  supports (intmax_t)

o there is a new \D{...} prompt expansion; passes the `...' to strftime(3)
  and inserts the result into the expanded prompt

o there is a 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).

o `read' has a new `-u fd' option to read from a specified file descriptor

o 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

o 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

Bash-2.05a introduced the following new features:

o The `printf' builtin has undergone major work

o There is a new read-only `shopt' option: login_shell, which is set by
  login shells and unset otherwise

o New `\A' prompt string escape sequence; expanding to time in 24-hour
  HH:MM format

o New `-A group/-g' option to complete and compgen; goes group name
  completion

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

o ksh-like `ERR' trap

o `for' loops now allow empty word lists after the `in' reserved word

o new `hard' and `soft' arguments for the `ulimit' builtin

o Readline can be configured to place the user at the same point on the line
  when retrieving commands from the history list

o Readline can be configured to skip `hidden' files (filenames with a leading
  `.' on Unix) when performing completion

Bash-2.05 introduced the following new features:

o This version has once again reverted to using locales and strcoll(3) when
  processing pattern matching bracket expressions, as POSIX requires. 
o Added a new `--init-file' invocation argument as a synonym for `--rcfile',
  per the new GNU coding standards.
o The /dev/tcp and /dev/udp redirections now accept service names as well as
  port numbers.
o `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
o A new loadable builtin, realpath, which canonicalizes and expands symlinks
  in pathname arguments.
o 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.

Bash-2.04 introduced the following new features:

o Programmable word completion with the new `complete' and `compgen' builtins;
  examples are provided in examples/complete/complete-examples
o `history' has a new `-d' option to delete a history entry
o `bind' has a new `-x' option to bind key sequences to shell commands
o The prompt expansion code has new `\j' and `\l' escape sequences
o The `no_empty_cmd_completion' shell option, if enabled, inhibits
  command completion when TAB is typed on an empty line
o `help' has a new `-s' option to print a usage synopsis
o New arithmetic operators: var++, var--, ++var, --var, expr1,expr2 (comma)
o New ksh93-style arithmetic for command:
	for ((expr1 ; expr2; expr3 )); do list; done
o `read' has new options: `-t', `-n', `-d', `-s'
o The redirection code handles several filenames specially:  /dev/fd/N,
  /dev/stdin, /dev/stdout, /dev/stderr
o The redirection code now recognizes /dev/tcp/HOST/PORT and
  /dev/udp/HOST/PORT and tries to open a TCP or UDP socket, respectively,
  to the specified port on the specified host
o The ${!prefix*} expansion has been implemented
o A new FUNCNAME variable, which expands to the name of a currently-executing
  function
o The GROUPS variable is no longer readonly
o A new shopt `xpg_echo' variable, to control the behavior of echo with
  respect to backslash-escape sequences at runtime
o The NON_INTERACTIVE_LOGIN_SHELLS #define has returned

The version of Readline released with Bash-2.04, Readline-4.1, had several
new features as well:

o Parentheses matching is always compiled into readline, and controllable
  with the new `blink-matching-paren' variable
o The history-search-forward and history-search-backward functions now leave
  point at the end of the line when the search string is empty, like
  reverse-search-history, and forward-search-history
o A new function for applications:  rl_on_new_line_with_prompt()
o New variables for applications:  rl_already_prompted, and rl_gnu_readline_p


Bash-2.03 had very few new features, in keeping with the convention
that odd-numbered releases provide mainly bug fixes.  A number of new
features were added to Readline, mostly at the request of the Cygnus
folks.

A new shopt option, `restricted_shell', so that startup files can test
	whether or not the shell was started in restricted mode
Filename generation is now performed on the words between ( and ) in
	compound array assignments (this is really a bug fix)
OLDPWD is now auto-exported, as POSIX.2 requires
ENV and BASH_ENV are read-only variables in a restricted shell
Bash may now be linked against an already-installed Readline library,
	as long as the Readline library is version 4 or newer
All shells begun with the `--login' option will source the login shell
	startup files, even if the shell is not interactive

There were lots of changes to the version of the Readline library released
along with Bash-2.03.  For a complete list of the changes, read the file
CHANGES in the Bash-2.03 distribution.

Bash-2.02 contained the following new features:

a new version of malloc (based on the old GNU malloc code in previous
	bash versions) that is more page-oriented, more conservative
	with memory usage, does not `orphan' large blocks when they
	are freed, is usable on 64-bit machines, and has allocation
	checking turned on unconditionally
POSIX.2-style globbing character classes ([:alpha:], [:alnum:], etc.)
POSIX.2-style globbing equivalence classes
POSIX.2-style globbing collating symbols
the ksh [[...]] extended conditional command
the ksh egrep-style extended pattern matching operators
a new `printf' builtin
the ksh-like $(<filename) command substitution, which is equivalent to
	$(cat filename)
new tilde prefixes that expand to directories from the directory stack
new `**' arithmetic operator to do exponentiation
case-insensitive globbing (filename expansion)
menu completion a la tcsh
`magic-space' history expansion function like tcsh
the readline inputrc `language' has a new file inclusion directive ($include)