GNU Bourne Again SHell
Bash is an sh-compatible command language interpreter that executes
commands read from the standard input or from a file. Bash also
incorporates useful features from the Korn and C shells (ksh and csh).
Bash is ultimately intended to be a conformant implementation of the
IEEE POSIX Shell and Tools specification (IEEE Working Group 1003.2).
The Programmable Completion Code, by Ian Macdonald, is now found in
the bash-completion package.