Bash is a Unix shell and command language written by Brian Fox as a free software replacement for the Bourne shell.
The shell's name is an acronym for Bourne-again shell. It was first released in 1989 and is the default login shell for many Linux distributions, and likely the most popular shell used overall. It is also the shell used for Apple's macOS. A version is also available for Windows 10. The Bash command syntax is a superset of the Bourne shell command set.
There are numerous ways you can install or use Bash. Below are several: