This is GNU Bash.  Bash is the GNU Project's Bourne Again SHell,
a complete implementation of the POSIX.2 shell spec, but also
with interactive command line editing, job control on architectures
that support it, csh-like features such as history substitution and
brace expansion, and a slew of other features. 

WWW: http://cnswww.cns.cwru.edu/~chet/bash/bashtop.html