The first beta release of bash-5.0 is now available with the URL ftp://ftp.cwru.edu/pub/bash/bash-5.0-beta.tar.gz
and from the bash-5.0-testing branch in the bash git repository (http://git.savannah.gnu.org/cgit/bash.git/log/?h=bash-5.0-testing). This tar file includes the formatted documentation (you should be able to generate updated versions yourself). This release fixes several outstanding bugs in bash-4.4 and introduces several new features. The most significant bug fixes are an overhaul of how nameref variables resolve and a number of potential out-of-bounds memory errors discovered via fuzzing. There are a number of changes to the expansion of $@ and $* in various contexts where word splitting is not performed to conform to a Posix standard interpretation. The most notable new features are several new shell variables: BASH_ARGV0, EPOCHSECONDS, and EPOCHREALTIME. The `history' builtin can remove ranges of history entries and understands negative arguments as offsets from the end of the history list. There is an option to allow local variables to inherit the value of a variable with the same name at a preceding scope. There is a new shell option that, when enabled, causes the shell to attempt to expand associative array subscripts only once (this is an issue when they are used in arithmetic expressions). The `globasciiranges' shell option is now enabled by default; it can be set to off by default at configuration time. There are a few incompatible changes between bash-4.4 and bash-5.0. The changes to how nameref variables are resolved means that some uses of namerefs will behave differently, though I have tried to minimize the compatibility issues. By default, the shell only sets BASH_ARGC and BASH_ARGV at startup if extended debugging mode is enabled; it was an oversight that it was set unconditionally and caused performance issues when scripts were passed large numbers of arguments. `bashbug' may be used to report bugs with this version. It will send mail to chet.ra...@case.edu if the shell's `release status' is alpha or beta. As always, thanks for your help. Chet +========== CHANGES ==========+ This document details the changes between this version, bash-5.0-beta, and the previous version, bash-5.0-alpha. 1. Changes to Bash a. Fixed a bug that allowed subshells to "inherit" enclosing loops -- this is where POSIX says the subshell is not "enclosed" by the loop. b. Added more UTF-8-specific versions of multibyte functions, and optimized existing functions if the current locale uses UTF-8 encoding. c. In POSIX mode, assignments preceding regular builtins should not persist when the builtin completes. d. Added additional checks to special array assignment (e.g., BASH_ALIASES) so it can't be used to bypass validity checks performed in other places. e. The `!!' history expansion now refers to the previous history entry as expected, even if used on the second or subsequent line of a multi-line history entry. f. Fixed a bug that could cause the shell to dereference a NULL pointer if the environment (`environ') is set to NULL. g. Bash uses slightly better integer overflow handling for brace sequence expansion on systems where ints are 32 bits and intmax_t is 64 bits. h. Fixed a bug setting attributes for a variable named as an argument to `declare' that also appears as a nameref in the temporary environment. i. Fixed several bugs that could cause assignments to namerefs to create variables with invalid names. j. Fixed a bug that could result in the SIGINT handler being set incorrectly in asynchronous subshells. k. Fixed a bug that could cause `bash -t' to not execute the specified command. l. Fixed several bugs that caused the shell to operate on the wrong variable when using namerefs with the same name as a global variable in shell functions. m. Internal changes to how the shell handles variables with invalid names in the initial environment and to prevent variables with invalid names from being added to the environment instead of passing them on to children. n. Changes to make sure that an expansion that results in a quoted null string is reflected in the expansion, even if the word expands to nothing. o. Changes to make sure that $* and ${array[*]} (and $@/${array[@]}) expand the same way after the recent changes for POSIX interpretation 888. p. Saving and restoring the positional parameters at function entry and exit is considerably more efficient; noticeably so when there are large numbers of positional parameters. q. Fixed a bug that caused `lastpipe' and `pipefail' to return an incorrect status for the pipeline if there was more than one external command in a loop body appearing in the last pipeline element. r. Fixed a bug that caused value conversion errors with the printf builtin's %u and %f conversion specifications and invalid constants. 2. Changes to Readline a. Added more UTF-8-specific versions of multibyte functions, and optimized existing functions if the current locale uses UTF-8 encoding. b. Fixed a problem with bracketed-paste inserting more than one character and interacting with other readline functions. c. Fixed a bug that caused the history library to attempt to append a history line to a non-existent history entry. d. If using bracketed paste mode, output a newline after the \r that is the last character of the mode disable string to avoid overwriting output. e. Fixes to the vi-mode `b', `B', `w', `W', `e', and `E' commands to better handle multibyte characters. f. Fixed a redisplay problem that caused an extra newline to be generated on accept-line when the line length is exactly the screenwidth. 3. New Features in Bash a. Bash no longer allows variable assignments preceding a special builtin that changes variable attributes to propagate back to the calling environment unless the compatibility level is 44 or lower. b. You can set the default value for $HISTSIZE at build time in config-top.h. c. The `complete' builtin now accepts a -I option that applies the completion to the initial word on the line. d. The internal bash malloc now uses mmap (if available) to satisfy requests greater than 128K bytes, so free can use mfree to return the pages to the kernel. e. The shell doesn't automatically set BASH_ARGC and BASH_ARGV at startup unless it's in debugging mode, as the documentation has always said, but will dynamically create them if a script references them at the top level without having enabled debugging mode. f. The localvar_inherit option will not attempt to inherit a value from a variable of an incompatible type (indexed vs. associative arrays, for example). g. The `globasciiranges' option is now enabled by default; it can be set to off by default at configuration time. 4. New Features in Readline a. The history expansion library now understands command and process substitution and extended globbing and allows them to appear anywhere in a word. b. The history library has a new variable that allows applications to set the initial quoting state, so quoting state can be inherited from a previous line. -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, UTech, CWRU c...@case.edu http://tiswww.cwru.edu/~chet/
