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tcsh ( , , or as an acronym, ) 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 system which inspired Ken Greer at Carnegie Mellon University, the author of tcsh, with its command-completion feature. Ken Greer began working on his code to implement Tenex-style file name completion in September 1975, finally merging it into the C shell in December 1981.
Mike Ellis at Fairchild A.I. Labs a...