mksh includes bug fixes and feature improvements, in order to produce a modern, robust shell good for interactive and especially script use. It has UTF-8 support (in substring operations and the Emacs editing mode) and, while R42b corresponds to OpenBSD 5.1-current ksh (without GNU bash-like PS1 and fancy character classes), adheres to SUSv4 and is much more robust. The code has been cleaned up and simplified, bugs fixed, standards compliance added, and several enhancements (for extended compatibility to other modern shells – as well as a couple of its own) are available. The build environment requirements are autoconfigured; mksh is portable to many unixoid operating systems and then some. It has sensible defaults as usual with BSD.

Online manual page: https://www.mirbsd.org/man1/mksh or (ISO A4 paper PDF) https://www.mirbsd.org/MirOS/dist/mir/mksh/mksh.pdf

For contributing, you may eMail to miros-mksh on the mirbsd.o®g domain, or if you prefer open up a bug at Launchpad against this project (NOT the package in Ubuntu or Debian, that is for packaging issues ONLY).