1) Free software programmed in C 
tcsh (l `tee-cee-shell`, l `tee-shell`, or as an acronym `tee cee ess aitch`) is a Unix shell based on and compatible with the C shell (csh). It is essentially the C shell with programmable command-line completion, command-line editing, and a few other features. ==History== The `t” in tcsh comes from the `T” in TENEX, an operating sy...
Open a Turbo C shell, see Section 3.2.3.2.