<Description xml:lang="en">bash (sh-compatible shell) The GNU Bourne-Again SHell. Bash is a sh-compatible command interpreter that executes commands read from the standard input or from a file. Bash also incorporates useful features from the Korn and C shells (ksh and csh). Bash is ultimately intended to be a conformant implementation of the IEEE Posix Shell and Tools specification (IEEE Working Group 1003.2). Bash must be present for the system to boot properly.