noun Technical meaning of c shell (operating system) (csh) The Unix command-line interpreter shell and script language by William Joy, originating from Berkeley Unix. Presumably, csh's C-like syntax was intended to endear it to programmers but sadly it lacks some sh features which are useful for writing shell scripts so you need to know two different syntaxes for every shell construct. A plethora of different shells followed csh, e.g. tcsh, ksh, bash, rc, but sh and csh are the only ones which are provided with most versions of Unix. 1
