Bash, though typically not capitalized, is an acronym for "Bourne-Again Shell" and is named after Stephen Bourne, the creator of the Unix shell "sh." It is a command language interpreter derived from sh that can execute commands entered at a command prompt and process text file input.
Bash (bash) supports all the commands of the original Bourne shell (sh), as well as many others. It also includes features from the Korn shell (ksh) and C shell (csh), such as command line editing, command substitution syntax, and command history. Bash also supports "brace expansion," which is used to generate related text strings. This operation provides an efficient way to search for filenames and rename multiple files. Newer versions of Bash support regular expressions (Bash 3.0) and associative arrays (Bash 4.0).
Bash was originally developed by Brian Fox for the GNU Project and was released in 1989. The bash shell was initially distributed with the GNU operating system and later became the default shell for multiple Linux distributions and Mac OS X. Recent versions of Bash (versions 3 and 4) were developed by Chet Ramey and are currently published by the Free Software Foundation, the same organization that distributes the GNU operating system.