The MirBSD Korn Shell (mksh) is an actively developed successor of pdksh (the Public Domain Korn Shell), aimed at producing a shell good for interactive use, but with the primary focus on scripting. It is intended to be portable to most *nix-like operating systems as long as they're not too obscure. mksh incorporates improvements from OpenBSD and Debian, as well as bugfixes and enhancements developed for the MirOS, FreeWRT, and MidnightBSD projects and Android. The emacs command line editing mode is UTF-8 capable, and Byte Order Marks are ignored in scripts. The shell supports large files, as well as all pdksh and some csh, AT&T ksh, zsh, and GNU bash features, is compatible with the Bourne shell and POSIX (within limits), has no limit on array sizes, and incorporates some other useful builtins and features. While being already fast and small (without losing functionality), flags to make it even smaller can be given at compile time. An interactive shell reads "~/.mkshrc" on startup.
The d command runs a command in the background and redirects its output to a file. The output file is annotated with start and end time, the actual command used, cwd, host, etc. You can ask the d command to extract the last command from the output file and run it again, you can ask it to append to the file or not, and other goodies. It comes with handy little programs to look at the output, tail it, etc. It is sort of trivial, but has been streamlined over many years.
PyDSH is a toolset to help simplify the administration of remote systems. The pydsh command enables running of a command on multiple hosts in parallel over RSH, SSH, or telnet, and manages your SSH public and private keys. The pydcp command enables SCP-like functions to and from multiple hosts in parallel.
Iron Bars SHell is a restricted Unix shell. The user can not step out of, nor access, files outside the home directory. Two ASCII configuration files are used for more control. The system administrator can define which commands may be executed by the user. No other executables are allowed. The admin also has the opportunity to define what kind of files the user may create. If a file has a certain extension (such as .mp3, .c, etc.), ibsh automatically erases it.
BUSH (Business Shell) combines the capabilities of BASH, PHP, GCC, and databases into a uniform design for rapidly building secure, reliable Web sites. Based on an ISO standard, it promotes code reuse: scripts and templates can be compiled with GCC or ported to JVM or .Net using third party tools with only minor changes. It can also replace BASH as an interactive command shell with SQL support, and is a general purpose scripting language.