bash

Bash (Bourne Again Shell) is the free and enhanced version of the Bourne shell distributed with Linux and GNU operating systems. Bash is similar to the original, but has added features such as command-line editing. Created to improve on the earlier Bourne shell (named sh), Bash includes features from the Korn shell and the C shell. Bash is intended to conform to the shell standard specified as part of IEEE POSIX. A command language script written for the Bourne shell should also run in the bash shell. Bash is released under the GNU General Public License (GPL), and it is available for most versions of Unix and Linux and versions have been ported to MS-DOS and Windows. As explained in the Bash Reference Manual, the name bash is an acronym of "Bourne-again SHell" which is a pun on Stephen Bourne, author of the Bourne shell. Bash is a superset of the earlier shell, and generally compatible with Bourne shell programs.