Interix provides two shells: the Korn shell and the C shell. The Korn shell, which is the binary file /bin/ksh, is a POSIX.2-conforming shell. (The file /bin/sh is a copy of /bin/ksh.) The C shell, which is the binary file /bin/csh, is an implementation of the Tenex C shell (the binary tcsh). They both support all standard shell features, such as job control, command pipelines, and #! script interpretation.
The Bourne shell is the default shell on most UNIX platforms. It is incompatible with the C shell in some important ways, such as in the syntax of its scripting language. The Korn shell contains many of the best features from both the Bourne and C shells, and is backwards compatible with almost all Bourne-shell scripts. Many people prefer the C shell as their interactive shell, but use the Bourne shell or Korn shell as their script processor. If portability is a concern, it is recommended that you use the Korn shell.
For information about starting a shell, see To start the Interix Korn shell, or To start the Interix C shell.