The C shell (csh) is a Unix shell developed by William Joy for the BSD Unix system. Its syntax is modeled after the C programming language. The C shell added many feature improvements over the Bourne shell, such as aliases and command history. Today, the C shell is not in wide use; it has been superseded by other shells such as tcsh, the Korn shell (ksh), and the GNU Bourne-Again shell (bash).

External Links

C Shell programming considered harmful (by Tom Christiansen) (http://www.faqs.org/faqs/unix-faq/shell/csh-whynot/)