Announcing: KornShell 93u+m/1.0.8
https://github.com/ksh93/ksh

Here is the eighth ksh 93u+m/1.0 bugfix release. It fixes a bug that caused
an incorrect default exit status for 'exit' within a trap action, as well as
a race condition (introduced in 1.0.7) occurring on some systems when
running an external command with a redirection from a command substitution.

Further below is an overview of the main changes. For greater detail, see
the NEWS file in the distribution. For complete detail, see the git(1)
commit log, which has full documentation of every significant change.

### HOW TO GET IT ###

Please download the source code tarball from our GitHub releases page:
https://github.com/ksh93/ksh/releases
To build, follow the instructions in README.md or src/cmd/ksh93/README.

Or ask your distribution package manager to upgrade ksh to this version.

### ABOUT KSH ###

KornShell (ksh) is a full-featured and very fast shell script interpreter
and interactive command shell with a distinguished lineage: it is a direct
descendant of the Bourne shell and, like its ancestor, was developed at
AT&T, the birthplace of UNIX. ksh has been open source since 2000.

But when AT&T terminated development in 2020, ksh was left buggy and
unreliable. ksh 93u+m aims to fix this situation whilst maintaining and
growing the tradition. For now, we are focusing mostly on fixing bugs and
egregious flaws but we also prioritise backward compatibility, performance,
portability, and occasionally adding a feature. Work on ksh 93u+m started in
May 2020, based on the last AT&T stable release, ksh 93u+.

Unique ksh features include discipline functions (every variable expansion
or assignment can trigger a shell function call determining its value),
static scoping of local variables in functions, the ability to define your
own data types, customisable tilde expansion (new in 93u+m), a shell option
for file system case (in)sensitivity detection for pathname expansion and
file name completion (new in 93u+m), and much more.

### CONTRIBUTORS ###

Main ksh 93u+m developers: Martijn Dekker, Johnothan King, hyenias

Direct contributors: Andy Fiddaman, Anuradha Weeraman, atheik, Chase,
Cy Schubert, Govind Kamat, Harald van Dijk, K. Eugene Carlson, Lev
Kujawski, Marc Wilson, Phi, Ryan Schmidt, rymrg, Sterling Jensen,
Trey Valenta, Vincent Mihalkovic

Also includes backported contributions by: David Korn, Glenn Fowler,
Lefteris Koutsofios, Siteshwar Vashisht, Kurtis Rader, Roland Mainz,
Finnbarr P. Murphy, Lijo George, OpenSUSE ksh 93u+ patch authors, Red Hat
ksh 93u+ path authors, Solaris ksh 93u+ patch authors, Debian ksh 93u+
patch authors, Apple ksh 93u+ patch authors, Graphviz maintainers

Many fixes have also been backported from the AT&T 93v- beta as well as the
former AT&T ksh2020 project lead by Kurtis Rader and Siteshwar Vashisht; we
appreciate and benefit from their work. Many thanks also to Siteshwar for
graciously donating his 'ksh93' GitHub organisation account!

### HOW TO GET INVOLVED ###

To report a bug, please open an issue at our GitHub page (see above).
Alternatively, email me at martijn@inlv.org with your report.
To get involved in development, read the brief policy information in
README.md and then jump right in with a pull request or email a patch.
Feel free to use Discussions to introduce yourself to the community.

You can also join the mailing list/Google group at:
https://groups.google.com/g/korn-shell

### MAIN CHANGES between ksh 93u+m/1.0.7 and 93u+m/1.0.8 ###

- Fixed a regression in the behavior of 'exit' in a trap action. The exit
status used when no argument is given to 'exit' is now once again the exit
status of the last command executed *before* the trap action.
- Fixed a race condition, introduced in 1.0.7, that occurred on some systems
when running an external command with a standard output redirection from a
command substitution.
- Fixed an init-time crash on failure to trim the shell command history file
due to a non-writable parent directory; ksh now prints a warning instead.
- The 'kill' built-in command now correctly refuses to issue SIGSTOP to the
shell's own process if the shell is a login shell.

### MAIN CHANGES between ksh 93u+m/1.0.6 and 93u+m/1.0.7 ###

- Fixed a hang in command substitutions (introduced in 93u+m/1.0.0) that was
triggered when redirecting standard output within a command substitution,
in combination with other factors. E.g., the following no longer hangs:
{ v=$(redirect 2>&1 1>&9); } 9>&1
- Fixed a crash on trying to append an indexed array value to an unset name
reference, e.g.: nameref unsetref; unsetref+=(foo bar). This now produces
a "removing nameref attribute" warning before performing the assignment.
- Fixed: assignments like name=(...) to arrays did not preserve the array
and variable types; similarly, assigning an empty set () to a compound
indexed array caused the -C attribute to be lost.
- Fixed incorrect rejection of the tab key while reading input using the
'read' built-in command.
- Fixed a bug in printf %T: when using dates and times in the past, time
zones for the present were incorrectly used, ignoring historical changes.

### MAIN CHANGES between ksh 93u+m/1.0.5 and 93u+m/1.0.6 ###

- Fixed a serious regression in pathname expansion where quoted wildcard
characters were incorrectly expanded if a pattern contains both a brace
expansion and a variable expansion.
- Fixed a bug where the command to launch a full-screen editor (^X^E in
emacs and 'v' in vi) could cause the wrong command line to be edited
if two shell sessions share a .sh_history file.

### MAIN CHANGES between ksh 93u+m/1.0.4 and 93u+m/1.0.5 ###

- Fixed various bugs causing crashes.
- Fixed many bugs in the emacs and vi line editors, in command completion,
and in file name completion.
- Fixed various bugs in the handling of quotes, backslash escapes and braces
when processing shell glob patterns (e.g. in pathname expansion and 'case').
- ksh now throws a panic and exits if a read error (such as an I/O error)
occurs while trying to read the next command(s) from a running script.
- Fixed many bugs in 'printf' and 'print -f' built-in commands, including:
. Multiple bugs causing incorrect output for relative date specifications,
e.g., printf %T\\n 'exactly 20 months ago' now outputs a correct result.
. More printf bugs with mix and match of % and %x$.
. A data corruption bug when using %B with 'printf -v varname'.
. A bug causing double evaluation of arithmetic expressions.
- Fixed a bug where 'unset -f commandname', executed in a subshell, hides
any built-in command by the same name for the duration of that subshell.
- Fixed ${var/#/string} and ${var/%/string} (with anchored empty pattern)
to work as on mksh, bash and zsh; these are no longer ineffective.
- Fixed incorrect result of array slicing ${array[@]:offset:length} where
'length' is a nested expansion involving an array.
- Command names can now end in ':' as they can on other shells.
- Fixed a spurious syntax error in compound assignments upon encountering a
pair of repeated opening parentheses '(('.
- Fixed spurious syntax error in ${parameter:offset:length}: the arithmetic
expressions 'offset' and 'length' may now contain the operators ( ) & |.
- Fixed a parsing bug in the declaration of .sh.math.* arithmetic functions.
- Fixed nameref self-reference loop detection for more than two namerefs.
- Several improvements to the POSIX compatibility mode.
- Many more minor and/or esoteric bugfixes.

### MAIN CHANGES between ksh 93u+m/1.0.3 and 93u+m/1.0.4 ###

- Fixed multiple scoping-related bugs in the += additive assignment operator.
- A number of crashing bugs have been fixed.
- Various fixes for the Haiku operating system, notably 'ulimit -a' now works.
- Fixed the expansion of out-of-range \n back references in the string part of
${parameter//pattern/string}. For example: v=AB; echo "${v/@(A)B/\0:\1:\2}"
now yields 'AB:A:' instead of 'AB:A:\2'.
- Fixed quoted '!', '^' and '-' within [bracket] expressions in glob patterns;
single or double quotes failed to disable their operator behaviour.
- Fixed a bug introduced on 2021-04-04 that incorrectly allowed 'typeset' to
turn off the readonly and export attributes on a readonly variable.
- In the emacs line editor, the Ctrl+R reverse-search prompt is now visually
distinct from a literal control character ("^R: " instead of "^R").
- In the vi line editor, fixed the behaviour of 'C', 'c$' and 'I' to be
consistent with standard vi(1) and with Bolsky & Korn (1995, p. 121).
- Aliases for many GNU long options have been added to the /opt/ast/bin
built-in commands. Additionally, 'kill -s' now has a --signal long option
alias compatible with the util-linux option.
- Backported support for 'print -u p' from ksh 93v- for compatibility with
scripts written for 93v-/ksh2020 (this is equivalent to 'print -p').