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