sudo ln /bin/zsh /bin/kshThis must be a hard link to function correctly. The zsh page suggests a soft link, which on other UNIX systems seems to work, but Darwin apparently requires a hard link for it to function properly. Like bash, zsh "senses" how you invoke it (ksh vs. zsh; sh vs. bash) and sets defaults for the shell session accordingly.
You can also install ksh93 via fink unstable and then hard link it in the same way. Using zsh, however, is much more straightforward.

