Bash-4.0-rc1 available for FTP
Chet Ramey
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 ${array[@]: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 ch...@case.edu http://tiswww.tis.case.edu/~chet/
Matthew Woehlke
> 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.
Does this mean that
$ sleep 60 ; do-something
...will no longer run 'do-something' when ctrl-C'd?
--
Matthew
Please do not quote my e-mail address unobfuscated in message bodies.
--
Your eyes are weary from staring at the CRT. You feel sleepy. Notice how
restful it is to watch the cursor blink. Close your eyes. The opinions
stated above are yours. You cannot imagine why you ever felt otherwise.
-- Unknown
(found at http://goldmark.org/jeff/stupid-disclaimers/fun.html)
Chet Ramey
> Chet Ramey wrote:
>> 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.
>
> Does this mean that
> $ sleep 60 ; do-something
> ...will no longer run 'do-something' when ctrl-C'd?
Yes.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
Chet Ramey, ITS, CWRU ch...@case.edu http://cnswww.cns.cwru.edu/~chet/
Matthew Woehlke
> Matthew Woehlke wrote:
>> Chet Ramey wrote:
>>> 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.
>> Does this mean that
>> $ sleep 60 ; do-something
>> ...will no longer run 'do-something' when ctrl-C'd?
>
> Yes.
Cool :-). Thanks for that enhancement!