What is Bash
Bash, the Bourne-Again Shell, refers to both a specific UNIX shell and an associated scripting language. It was initially written for the GNU project and first released in 1989 and is the default shell of Linux and Apple’s macOS as well as now is distributed in the Windows 10 Anniversary Update! Just as a note, the name of the shell ‘Bourne-again shell’ is punned on the name of the Bourne shell that it replaced and also on the term ‘born again’, point to the spiritual re-birthing in the American Christianity.
Due to the fact that it is a commanding language and processor, it runs inside text windows where the commands are needed to be typed. Along with that, Bash also reads comments from any file and supports globbing, command substitution and control structures, and so on. It is mainly a POSIX (Portable Operating System Interface) shell with a number of extensions and is also Unix’s sh-compatible, which incorporates the important features from C shell (csh) or Korn shell (ksh).
Let's do a simple "Hello world!" with Bash shell.