In functionality bash goes well beyond the original Bourne shells and closely matches the extensions of David Korn's "Korn Shell" (ksh), though bash and ksh use different syntax to create a coprocess or an associative array. bash also adds a number of interactive features drawn from Bill Joy's C Shell (including the many "bang expansion operators" for things like !! (expand to entire previous command), !-2 (expand to penultimate command), !$ (expand to last argument of previous command) etc).
(Redirected from Bourne Again Shell)
Unix shell which is intended to be compatible with the original UNIX Bourne Shell (/bin/sh) by Stephen R. Bourne. bash was primarily written and is maintained by Brian Fox and Chet Ramey. The name follows a Free Software Foundation tradition for whimsical and pun-referential names.