Bash-4.2 available for FTP
Chet Ramey
============
The first public release of bash-4.2 is now available with the URLs
ftp://ftp.cwru.edu/pub/bash/bash-4.2.tar.gz
ftp://ftp.gnu.org/pub/gnu/bash/bash-4.2.tar.gz
and from the usual GNU mirror sites.
This tar file includes the formatted documentation (postscript, dvi, html,
and nroffed versions of the manual pages).
Diffs from bash-4.1 are not available.
Please use `bashbug' to report bugs with this version. It is built
and installed at the same time as bash.
Installation
============
Please read the README file first.
Installation instructions are provided in the INSTALL file.
New Features
============
This is the second revision to the fourth major release of bash.
This release fixes several outstanding bugs in bash-4.1 and introduces
several new features.
The most notable new features are \u and \U unicode character escapes
for the echo and printf builtins and $'...' quoting, a new mechanism
to declare variables with attributes in the global scope from a shell
function, and new word expansion features. There are also a number of
changes to accommodate recent Posix shell interpretations, changing the
bash posix-mode behavior to align with the newly-intepreted standard.
Read the file NEWS in the bash-4.2 distribution for a complete
description of the new features. A copy of the relevant portions
is included below.
Changes have been made to the Readline library being released at
the same time as bash-4.2, readline-6.2, so that Bash can be
linked against an already-installed Readline library rather than
the private version in lib/readline. Only readline-6.0 and later
versions are able to provide all of the symbols that bash-4.2
requires; earlier versions of the Readline library will not work
correctly.
A complete list of changes between bash-4.1 and bash-4.2 is
available in the file CHANGES; the complete list is too large to
include in this message.
Readline
========
Also available is a new release of the standalone Readline library,
version 6.2, with its own configuration scripts and Makefiles.
It can be retrieved with the URLs
ftp://ftp.cwru.edu/pub/bash/readline-6.2.tar.gz
ftp://ftp.gnu.org/pub/gnu/readline/readline-6.2.tar.gz
and from the usual GNU mirror sites.
Diffs from readline-6.1 are not available.
The formatted Readline documentation is included in the readline
distribution tar file.
A separate announcement listing the changes in Readline is being
distributed.
As always, thanks for your help.
Chet
+========== NEWS ==========+
This is a terse description of the new features added to bash-4.2 since
the release of bash-4.1. As always, the manual page (doc/bash.1) is
the place to look for complete descriptions.
1. New Features in Bash
a. `exec -a foo' now sets $0 to `foo' in an executable shell script without a
leading #!.
b. Subshells begun to execute command substitutions or run shell functions or
builtins in subshells do not reset trap strings until a new trap is
specified. This allows $(trap) to display the caller's traps and the
trap strings to persist until a new trap is set.
c. `trap -p' will now show signals ignored at shell startup, though their
disposition still cannot be modified.
d. $'...', echo, and printf understand \uXXXX and \UXXXXXXXX escape sequences.
e. declare/typeset has a new `-g' option, which creates variables in the
global scope even when run in a shell function.
f. test/[/[[ have a new -v variable unary operator, which returns success if
`variable' has been set.
g. Posix parsing changes to allow `! time command' and multiple consecutive
instances of `!' (which toggle) and `time' (which have no cumulative
effect).
h. Posix change to allow `time' as a command by itself to print the elapsed
user, system, and real times for the shell and its children.
j. $((...)) is always parsed as an arithmetic expansion first, instead of as
a potential nested command substitution, as Posix requires.
k. A new FUNCNEST variable to allow the user to control the maximum shell
function nesting (recursive execution) level.
l. The mapfile builtin now supplies a third argument to the callback command:
the line about to be assigned to the supplied array index.
m. The printf builtin has a new %(fmt)T specifier, which allows time values
to use strftime-like formatting.
n. There is a new `compat41' shell option.
o. The cd builtin has a new Posix-mandated `-e' option.
p. Negative subscripts to indexed arrays, previously errors, now are treated
as offsets from the maximum assigned index + 1.
q. Negative length specifications in the ${var:offset:length} expansion,
previously errors, are now treated as offsets from the end of the variable.
r. Parsing change to allow `time -p --'.
s. Posix-mode parsing change to not recognize `time' as a keyword if the
following token begins with a `-'. This means no more Posix-mode
`time -p'. Posix interpretation 267.
t. There is a new `lastpipe' shell option that runs the last command of a
pipeline in the current shell context. The lastpipe option has no
effect if job control is enabled.
u. History expansion no longer expands the `$!' variable expansion.
v. Posix mode shells no longer exit if a variable assignment error occurs
with an assignment preceding a command that is not a special builtin.
w. Non-interactive mode shells exit if -u is enabled and an attempt is made
to use an unset variable with the % or # expansions, the `//', `^', or
`,' expansions, or the parameter length expansion.
x. Posix-mode shells use the argument passed to `.' as-is if a $PATH search
fails, effectively searching the current directory. Posix-2008 change.
2. New Features in Readline
a. The history library does not try to write the history filename in the
current directory if $HOME is unset. This closes a potential security
problem if the application does not specify a history filename.
b. New bindable variable `completion-display-width' to set the number of
columns used when displaying completions.
c. New bindable variable `completion-case-map' to cause case-insensitive
completion to treat `-' and `_' as identical.
d. There are new bindable vi-mode command names to avoid readline's case-
insensitive matching not allowing them to be bound separately.
e. New bindable variable `menu-complete-display-prefix' causes the menu
completion code to display the common prefix of the possible completions
before cycling through the list, instead of after.
--
``The lyf so short, the craft so long to lerne.'' - Chaucer
``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, ITS, CWRU ch...@case.edu http://cnswww.cns.cwru.edu/~chet/