bash

The 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).
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Bash is ultimately intended to be a conformant implementation of the
IEEE POSIX Shell and Tools specification (IEEE Working Group 1003.2).
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The Programmable Completion Code, by Ian Macdonald, is now found in
the bash-completion package.