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Bash-4.0-rc1 available for FTP


From: Chet Ramey
Subject: Bash-4.0-rc1 available for FTP
Date: Mon, 12 Jan 2009 16:40:11 -0500

The first public release candidate of bash-4.0 is now available with the URL

ftp://ftp.cwru.edu/pub/bash/bash-4.0-rc1.tar.gz

This tar file does not include the formatted documentation (you
should be able to generate it yourself).

This release fixes the remaining serious bugs in the bash version 3 branch
and introduces significant new features.

The most notable new features are associative arrays, improvements to the
programmable completion functionality, case-modifying word expansions,
co-processes, support for the `**' special glob pattern, and additions to
the shell syntax and redirections.  The shell has been changed to be more
rigorous about parsing commands inside command substitutions, fixing one
piece of Posix non-compliance.

`bashbug' may be used to report bugs with this version.

As always, thanks for your help.

Chet

+========== CHANGES ==========+
This document details the changes between this version, bash-4.0-rc1,
and the previous version, bash-4.0-beta2.

1.  Changes to Bash

a.  Fixed a bug that caused parsing errors when a $()-style command
    substitution was follwed immediately by a quoted newline.

b.  Fixed a bug that caused extended shell globbing patterns beginning with
    `*(' to not work when used with pattern substitution word expansions.
 
------------------------------------------------------------------------------
This document details the changes between this version, bash-4.0-beta2,
and the previous version, bash-4.0-beta.

1.  Changes to Bash

a.  Fixed a bug that caused failed word expansions to set $? but not
    PIPESTATUS.

b.  Changed filename completion to quote the tilde in a filename with a
    leading tilde that exists in the current directory.

c.  Fixed a bug that caused a file descriptor leak when performing
    redirections attached to a compound command.

d.  Fixed a bug that caused expansions of $@ and $* to not exit the shell if
    the -u option was enabled and there were no posititional parameters.

e.  Fixed a bug that resulted in bash not terminating immediately if a
    terminating signal was received while performing output.

f.  Fixed a bug that caused the shell to crash after creating 256 process
    substitutions during word completion.

2.  Changes to Readline

a.  Fixed a bug that caused redisplay errors when using prompts with invisible
    characters and numeric arguments to a command in a multibyte locale.

b.  Fixed a bug that caused redisplay errors when using prompts with invisible
    characters spanning more than two physical screen lines.

------------------------------------------------------------------------------
This document details the changes between this version, bash-4.0-beta,
and the previous version, bash-4.0-alpha.

1.  Changes to Bash

a.  Fixed a typo that caused a variable to be used before initialization
    while parsing Posix-style command substitutions.

b.  Fixed a bug that caused stray ^? when the expansion of a parameter used
    as part of a pattern removal expansion is empty, but part of a non-
    empty string.

c.  Fixed a bug that could cause strings not converted to numbers by strtol
    to be treated as if the conversion had been successful.

d.  The `return' builtin now accepts no options and requires a `--' before
    a negative return value, as Posix requires.

e.  Fixed a bug that caused local variables to be created with the empty
    string for a value rather than no value.

f.  Changed behavior so the shell now acts as if it received an interrupt
    when a pipeline is killed by SIGINT while executing a list.

g.  Fixed a bug that caused `declare var' and `typeset var' to initialize
    `var' to the empty string.

h.  Changed `bind' builtin to print a warning but proceed if invoked when
    line editing is not active.

i.  Fixed a bug that caused the shell to exit when the `errexit' option is
    set and a command in a pipeline returns a non-zero exit status.

j.  Fixed a bug that caused the shell to not run the exit trap in a command
    run with `bash -c' under some circumstances.

k.  Fixed a bug that caused parser errors to occasionally not set $? when
    running commands with `eval'.

l.  Fixed a bug that caused stray control characters when evaluating compound
    array assignments containing $'\x7f' escapes.

m.  Fixed a bug that caused redirections involving file descriptor 10 as the
    target to behave incorrectly.

n.  Fixed a bug that could cause memory to be freed multiple times when
    assigning to COMP_WORDBREAKS.

o.  Fixed a bug that could cause NULL pointer dereferences when COMP_WORDBREAKS
    was unset.

2.  Changes to Readline

3.  New Features in Bash

a.  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.

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

c.  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.

d.  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.

4.  New Features in Readline

a.  If the kernel supports it, readline displays special characters
    corresponding to a keyboard-generated signal when the signal is received.

------------------------------------------------------------------------------
This document details the changes between this version, bash-4.0-alpha,
and the previous version, bash-3.2-release.

1.  Changes to Bash

a.  Fixed several bugs in old-style `` command substitution parsing, including
    comment parsing and quoted string handling.

b.  Fixed problems parsing arguments to the [[ command's =~ regular expression
    matching operator:  metacharacter and whitespace parsing.

c.  Fixed a bug that caused the shell to inappropriately reuse high-numbered
    file descriptors it used internally.

d.  Fixed a bug in pattern replacement word expansions that caused a `/' as
    the first character of an expanded pattern to be mistaken for a global
    replacement specifier.

e.  Fixed several problems with the asprintf and snprintf replacement functions
    that caused hangs and crashes.

f.  Fixed a bug in the calculation of the current and previous job that caused
    it to refer to incorrect jobs.

g.  Fixed a bug in the check for the validity of a hashed command pathname that
    caused unnecessary hash table deletions and additions.

h.  Fixed a bug that caused child processes to inherit the wrong value for $!.

i.  Fixed a bug that caused `.' to fail to read and execute commands from non-
    regular files such as devices or named pipes.

j.  Fixed a bug in printf formatting for the %x and %X expansions that occurred
    on some systems.

k.  Fixed a bug that caused the shell to crash when creating temporary files if
    $TMPDIR named a non-writable directory.

l.  Fixed a bug that caused the shell to ignore $TMPDIR when creating temporary
    files under some circumstances.

m.  Fixed a bug that caused named pipes created by process substitution to not
    be cleaned up.

n.  Fixed a bug that caused HISTTIMEFORMAT to not be honored when it appeared
    in the initial shell environment.

o.  Fixed several bugs in the expansion of $* and $@ (quoted and unquoted)
    when IFS is null or contains non-whitespace characters; the same changes
    apply to arrays subscripted with * or @.

p.  Fixed several problems with pattern substitution expansions on the
    positional parameters and arrays subscripted with * or @ that occurred
    when $IFS was set to the empty string.

q.  Made a change to the default locale initialization code that should
    result in better behavior from the locale-aware library functions.

r.  Fixed a bug that caused compacting the jobs list to drop jobs.

s.  Fixed a bug that caused jumps back to the top-level processing loop from
    a builtin command to leave the shell in an inconsistent state.

t.  Fixed a bug that caused characters that would be escaped internally to be
    doubled when escaped with a backslash.

u.  Fixed the initialization of mailboxes to not cause maildirs to be read
    (and stat(2) called for every message file) at shell startup.

v.  Fixed a bug that caused the shell to not display $PS2 when the read builtin
    reads a line continued with a backslash.

w.  Fixed a bug that caused errors in word splitting when $IFS contained
    characters used for internal quoting.

x.  Fixed bugs that caused problems with output from shell builtins not being
    completely displayed on some systems.

y.  Fixed a bug that caused output to be lost when a redirection is acting on
    the shell's output file descriptor.

z.  Fixed bugs caused by shell builtins not checking for all write errors.

aa. Fixed a problem that caused the shell to dump core if expansions on the
    pattern passed to the pattern removal word expansions resulted in expansion
    errors.

bb. Fixed a bug that caused bash to loop infinitely after creating and
    waiting for 4096 jobs.

cc. Fixed a bug that caused bash to lose the status of a background job under
    certain circumstances.

dd. Fixed a bug that caused bash to not look in the temporary environment
    when performing variable lookup under certain circumstances.

ee. Fixed a bug that caused bash to close file descriptors greater than 10
    when they were used in redirections.

ff. Fixed a problem that caused the shell to attempt to read from the standard
    input when called as `bash -i script'.

gg. Fixed a memory leak and variable initialization problems when the -v option
    was supplied to `printf' that could cause incorrect results.

hh. Fixed a bug that caused the `read' builtin to count bytes when the -n option
    was supplied, rather than (possibly multibyte) characters.

ii. Fixed a bug when displaying a function due to not converting the function
    to an external form.

jj. Changed job control initialization to ensure that the shell has a tty
    as its controlling terminal before enabling job control.

kk. Fixed a bug with the `test' builtin that caused it to misinterpret
    arguments beginning with `-' but containing more than one character.

ll. Fixed bug that could cause the shell to dump core in certain cases where
    a command sets the SIGINT disposition to the default.

mm. Fixed a bug in the pattern replacement (affecting both word expansion
    and the `fc' builtin) that occurred when the pattern and replacement
    strings were empty.

nn. Fixed a bug that caused an arithmetic evaluation error to disable all
    further evaluation.

oo. Fixed a bug in pathname expansion that caused it to interpret backslashes
    in the pathname as quoting characters.

pp. Fixed a bug in the replacement getcwd() implementation that could cause
    memory to be overwritten.

qq. When in Posix mode, the `ulimit' builtin now uses a block size of 512 for
    the `-c' and `-f' options.

rr. Brace expansion now allows process substitutions to pass through unchanged.

ss. Fixed a problem in the command name completion code to avoid quoting
    escaped special characters twice when the command name begins with a tilde.

tt. Fixed a problem in the printf builtin that resulted in single-byte
    output for the "'" escape, even when using multibyte characters.

uu. Fixed a bug that caused the failure exit status to be lost when redirections
    attached to a compound command failed.

vv. Fixed a bug that caused the internal random number generator to not be
    re-seeded correctly when creating a subshell.

ww. Fixed a bug that could cause the bash replacement getcwd to overwrite
    memory.

xx. Fixed a bug that caused the shell to not receive SIGINT if it was sent
    while the shell was waiting for a command substitution to terminate, and
    make sure the exit status is correct when it does.

yy. Fixed a bug that resulted in the second and subsequent children spawned
    by a shell begun to run a command substitution being placed into the
    wrong process group.

zz. Fixed a bug that caused the results of successful tilde expansion to be
    subject to pathname expansion and word splitting.

aaa. Fixed a bug that could cause the shell to hang if it encountered an
     error that caused it to jump back to the top processing loop during a
     command substitution or `eval' command.

bbb. Fixed a bug that caused the `read' builtin to use the tty's attributes
     instead of those of the file descriptor passed with the -u option when
     processing the -n and -d options.

ccc. Fixed a bug that caused incorrect expansion of address@hidden:foo} if the
     first character of $IFS was not whitespace.

ddd. Fixed a bug that occurred when scanning for the ending delimiter of a
     ${parameter/pat/sub} expansion.

eee. Fixed a bug that caused the shell to inappropriately expand command
     substitutions in words when expanding directory names for completion.

fff. Fixed a bug that caused the `fc' builtin to look too far back in the
     history list under certain circumstances.

ggg. Fixed a bug that caused a shell running in Posix mode to search $PWD for
     a file specified as an argument to source/. when the file was not found
     in $PATH.

hhh. Fixed a bug that caused the shell to modify the case of a command word
     found via command completion when the shell was performing case-
     insensitive completion.

iii. Fixed a bug that caused the shell to search $PATH for an argument to
     source/. even when it contained a `/'.

jjj. Fixed a bug that caused brace expansion to misorder expansions when the
     locale did not have a collating order like aAbBcC...zZ.

kkk. Fixed a bug that did not allow `set +o history' to have any effect when
     run in a startup file or from a sourced file.

lll. Fixed a bug with the precedence of the ?: conditional arithmetic operator.

mmm. Fixed a bug that caused side effects of temporary variable assignments
     to persist in the shell environment.

nnn. Fixed a bug that caused the terminal to be left in non-canonical mode
     when using editing commands that invoke the an editor on the current
     command line.

ooo. Fixed a bug that caused globbing characters and characters in $IFS to not
     be quoted appropriately when displaying assignment statements.

ppp. Fixed a bug that caused the `-e' option to be inherited when sourcing a
     file or evaluating a command with `eval' even if the return value of the
     command was supposed to be ignored.

qqq. Fixed a bug that caused the shell to attempt to created variables with
     invalid names if such names appeared in the initial environment.

rrr. Fixed a bug with quote removal in strings where the final character is a
     backslash.

sss. Fixed a bug that caused the effects of special variables to persist even
     when the variables were unset as part of the shell reinitializing itself
     to execute a shell script.

ttt. Fixed a bug that caused the history to not be saved after `history -c' or
     `history -d' was executed until a sufficient number of commands had been
     saved to the history.

uuu. Bash now parses command substitutions according to Posix rules: parsing
     the command contained in $() to find the closing delimiter.

vvv. Fixed a bug that caused traps on SIGCHLD set in a SIGCHLD handler to
     not persist.

www. Fixed a bug that didn't allow SIGCHLD to interrupt the `wait' builtin
     as Posix specifies.

xxx. Invalid numeric arguments to shell builtins no longer cause the shell to
     short-circuit any executing compound command.

yyy. Fixed a bug that caused the exit status to be lost when `break' was
     used to short-circuit a loop's execution.

zzz. Fixed a bug that caused stray ^? characters to be left in expansions of
     "${array[*]}".

aaaa. Bash now prints better error messages for here documents terminated by
      EOF and for identifying the incorrect token in an invalid arithmetic
      expression.

bbbb. Fixed a bug in the variable length word expansion that caused it to
      incorrectly calculate the number of multibyte characters.

cccc. Fixed a race condition that could result in the top-level shell setting
      the terminal's process group to an incorrect value if the process
      group was changed by a child of a child of the shell.

dddd. Fixed a bug that caused here documents belonging to commands within a
      compound command to be displayed in a syntactially-incorrect form, which
      prevented them from being re-read as input.

eeee. The shell displays more warnings about failures to set the locale.

ffff. Fixed a bug that caused the body of a here-document to not be saved to
      the history list.

gggg. Fixed a bug that caused configure to incorrectly conclude that FreeBSD
      had /dev/fd available, resulting in problems with process substitution.

2.  Changes to Readline

a.  Fixed a number of redisplay errors in environments supporting multibyte 
    characters.

b.  Fixed bugs in vi command mode that caused motion commands to inappropriately
    set the mark.

c.  When using the arrow keys in vi insertion mode, readline allows movement
    beyond the current end of the line (unlike command mode).

d.  Fixed bugs that caused readline to loop when the terminal has been taken
    away and reads return -1/EIO.

e.  Fixed bugs in redisplay occurring when displaying prompts containing
    invisible characters.

f.  Fixed a bug that caused the completion append character to not be reset to
    the default after an application-specified completion function changed it.

g.  Fixed a problem that caused incorrect positioning of the cursor while in
    emacs editing mode when moving forward at the end of a line while using
    a locale supporting multibyte characters.

h.  Fixed an off-by-one error that caused readline to drop every 511th
    character of buffered input.

i.  Fixed a bug that resulted in SIGTERM not being caught or cleaned up.

j.  Fixed redisplay bugs caused by multiline prompts with invisible characters
    or no characters following the final newline.

k.  Fixed redisplay bug caused by prompts consisting solely of invisible
    characters.

l.  Fixed a bug in the code that buffers characters received very quickly in
    succession which caused characters to be dropped.

m.  Fixed a bug that caused readline to reference uninitialized data structures
    if it received a SIGWINCH before completing initialzation.

n.  Fixed a bug that caused the vi-mode `last command' to be set incorrectly
    and therefore unrepeatable.

o.  Fixed a bug that caused readline to disable echoing when it was being used
    with an output file descriptor that was not a terminal.

p.  Readline now blocks SIGINT while manipulating internal data structures
    during redisplay.

q.  Fixed a bug in redisplay that caused readline to segfault when pasting a
    very long line (over 130,000 characters).

r.  Fixed bugs in redisplay when using prompts with no visible printing
    characters.

3.  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.

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.

4.  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.

-- 
``The lyf so short, the craft so long to lerne.'' - Chaucer

Chet Ramey, ITS, CWRU    address@hidden    http://tiswww.tis.case.edu/~chet/




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