Bash is the GNU Project's Bourne
Again SHell, an interactive shell with Bourne shell syntax (/bin/sh);
but also with interactive command line editing, job control on
architectures that support it, Csh-like history features and brace
expansion, and a slew of other stuff.  For more information on the
features of Bash that are new to this type of shell, see the file
`documentation/features.texi'.  There is also a processed DVI file
there, as well as a large man page.

WWW: http://www.gnu.org/software/bash/
