Bash usually refers to a shell, a computer program that accepts commands and scripts (see below). Bash is also the command language used by Bash shell and by some other UNIX-like shells.

Bash was first released in 1989. Its name is short for Bourne Again SHell. It refers to the earlier Bourne shell (sh), which Bash was designed to replace and improve.

Commands are textual instructions (eg: echo "Hello world" ) that are commonly given to the shell using a terminal emulator. Technically shell and terminal emulator are very different things, even though colloquially they are used interchangeably.

Scripts are plain text files containing commands. Scripts are not programs, because they need a program to open them and execute them. A Bash script needs Bash shell, while others (eg: Fish scripts) need a different one (eg: Fish shell).

Bash scripts usually begin with a line like #!/usr/bin/env bash or #!/bin/bash. This line is called a shebang, and serves to tell the operating system to run the script with Bash.

Bash is free and open-source software created for the GNU Project.

• GNU/Linux: Bash is preinstalled in many Linux distributions, most of the time being the default shell.
• MacOS: Bash has been present since 2003, it's been the default shell from 2003 to 2019 (until Catalina).
• Windows: Bash can be run on Windows 10 and Windows 11 through Windows Subsystem for Linux.
• Other: Bash also exist for FreeBSD, NetBSD, Solaris, MINIX.

• Command-line interface
• Scripting language
• GNU Project
• Linux

• GNU Bash home page: https://www.gnu.org/software/bash/ Archived 2019-04-26 at the Wayback Machine
• GNU Bash Manual: https://www.gnu.org/software/bash/manual/ Archived 2026-06-20 at the Wayback Machine