Updated ksh packages that fix several bugs and add various enhancements are now available for Red Hat Enterprise Linux 6.
KornShell (KSH) is a Unix shell developed by AT&T Bell Laboratories, which is backward-compatible with the Bourne shell (Bash) and includes many features of the C shell. The most recent version is KSH-93. KornShell complies with the POSIX.2 standard (IEEE Std 1003.2-1992).
The ksh package has been upgraded to upstream version 20120801, which provides a number of bug fixes and enhancements over the previous version. (BZ#840568)
- Previously, the ksh shell did not set any editing mode as default, which caused various usability problems in interactive mode and with shell auto-completion. This update sets emacs editing mode as default for new users. As a result, the usability is significantly improved and the shell auto-completion works as expected.
- Previously, the ksh internal counter of jobs was too small. Consequently, when a script used a number of subshells in a loop, a counter overflow could occur causing the ksh shell to terminate unexpectedly with a segmentation fault. This update modifies ksh to use bigger types for counter variables. As a result, ksh no longer crashes in the described scenario.
- Previously, the ksh shell did not compute an offset for fixed size variables correctly. As a consequence, when assigning a right-justified variable with a fixed width to a smaller variable, the new variable could have an incorrect content. This update applies a patch to fix this bug and the assignment now proceeds as expected.
- Previously, the output of command substitutions was not always redirected properly. Consequently, the output in a here-document could be lost. This update fixes the redirection code for command substitutions and the here-document now contains the output as expected.
- BZ#921455, BZ#982142
- Using arrays inside of ksh functions, command aliases, or automatically loaded functions caused memory leaks to occur. The underlying source code has been modified to fix this bug and the memory leaks no longer occur in the described scenario.
- Previously, the ksh SIGTSTP signal handler could trigger another SIGTSTP signal. Consequently, ksh could enter an infinite loop. This updated version fixes the SIGTSTP signal processing and ksh now handles the signal without any problems.
- Previously, the ksh shell did not resize the file descriptor list every time it was necessary. This could lead to memory corruption when several file descriptors were used. As a consequence, ksh terminated unexpectedly. This updated version resizes the file descriptor list every time it is needed, and ksh no longer crashes in the described scenario.
- Previously, the ksh shell ignored the "-m" argument specified by the command line. As a consequence, ksh did not enable monitor mode and the user had to enable it in a script. With this update, ksh no longer ignores the argument so that the user is able to enable monitor mode from the command line as expected.
- The ksh shell did not handle I/O redirections from command substitutions inside a pipeline correctly. Consequently, the output of certain commands could be lost. With this update, the redirections have been fixed and data is no longer missing from the command outputs.
Users of ksh are advised to upgrade to these updated packages, which fix these bugs and add these enhancements.