Bashs

Bash, short for Bourne Again SHell, is a Unix shell and command language that serves as the default interactive shell on many Linux distributions and is widely used for scripting on Unix-like systems. It provides a programmable interface for launching programs, managing processes, and performing text processing, with features such as command-line editing, history, and tab completion.

Origin and development: Bash was created by Brian Fox for the Free Software Foundation and first released in 1989 as a free software replacement for the Bourne shell. It was later maintained by Chet Ramey, with ongoing development that has produced many versions compatible with the POSIX standard.

Key features: As a superset of the original Bourne shell, Bash includes interactive features from Readline, a robust scripting language with variables, functions, and control structures, and support for arrays, associative arrays, arithmetic evaluation, command substitution, and process substitution. It supports here documents, brace and pathname expansions, and programmable completion through the Readline library.

Usage and compatibility: Bash scripts commonly start with a shebang such as #!/bin/bash and can run in POSIX sh-compatible mode or in non-POSIX extensions. It is the default on many Linux systems and is available on macOS, BSDs, and Windows environments through projects like WSL, Cygwin, and Git Bash. Bash remains widely documented and interoperable with other shells, though POSIX mode can affect behavior.

Note on terminology: The form Bashs is not standard English; Bash is a proper noun. When referring to multiple instances, many writers use Bash shells or simply Bash in the plural. This article uses Bash to denote the program family, with Bashs treated as a nonstandard plural.