This is GNU Bash, version 3.0. 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