What is Bash Script?

Bash (Bourne-Again SHell) is a Linux and Unix-like system shell or command language interpreter.Bash scripts an extension of .sh (an.sh for example).
Bash is useful when most of what you’re doing is communicating and piping between various programs (many of which are also standard). And there are many environments where bash (or at least a POSIX shell) is available but Perl and Python are not.