Editing Unix shell (section)

===C shell===
The [[C shell]], ''csh'', was modeled on the C programming language, including the control structures and the expression grammar. It was written by [[Bill Joy]] as a graduate student at [[University of California, Berkeley]], and was widely distributed with [[Berkeley Software Distribution|BSD Unix]].<ref>Harley Hahn, [https://www.harley.com/unix-book/book/chapters/h.html Harley Hahn's Guide to Unix and Linux: Unix/Linux Timeline].</ref>{{better source|date=September 2023}}

The C shell also introduced many features for interactive work, including the [[C shell#History|history]] and [[C shell#Editing operators|editing]] mechanisms, [[C shell#Aliases|aliases]], [[C shell#Directory stack|directory stacks]], [[C shell#Tilde notation|tilde notation]], [[C shell#Cdpath|cdpath]], [[C shell#Job control|job control]] and [[C shell#Path hashing|path hashing]].  On many systems, csh may be a [[symbolic link]] or [[hard link]] to [[TENEX C shell]] (tcsh), an improved version of Joy's original version.  Although the interactive features of csh have been copied to most other shells, the language structure has not been widely copied.  The only work-alike is [[Hamilton C shell]], written by Nicole Hamilton, first distributed on [[OS/2]] in 1988 and on [[Windows]] since 1992.<ref>{{cite web|url=http://hamiltonlabs.com/ReleaseNotes.htm|title=Hamilton C shell for Windows Release Notes 4.0|access-date=20 September 2014}}</ref>