C shell is a common UnixShell, whose command language is alleged to resemble CeeLanguage. In truth, it bears only a superficial resemblance to the C language.
C shell is a very popular interactive shell; one of the common Unix HolyWars is C shell vs KornShell. (The BourneShell, at least traditional implementations of it, is often regarded as a lesser shell for interactive purposes; kept around mainly for root to use when bootstrapping or repairing a system; many initialization utilities and scripts depend on the BourneShell).
As a ScriptingLanguage, however, the CeeShell is widely regarded as terrible. It has been the subject of at least one ConsideredHarmful paper; its flaws are legendary. Its syntax is unforgiving; the diagnostics are terrible, and many of its semantics are baroque or just plain broken.