The Bash command-line interpreter

The bash command-line interpreter (a.k.a., a shell) is one of the many command-line interpreters available. It is mostly present by default in most Linux distributions.

bash means Bourne-Again Shell. It is a complete GNU rewrite of the original UNIX shell, the Bourne Shell, named sh.

When starting a session on Unix or opening a terminal, the system runs the bash interpreter, which then waits for instructions from the user.