Bourne shell
also: sh, POSIX shell
The Bourne shell (sh) is the original Unix shell created by Stephen Bourne in 1979, serving as the standard command interpreter and scripting language for Unix and Unix-like systems including Linux.
The Bourne shell is the foundational shell that established many conventions still used in modern shells. It provides command-line interpretation, script execution, and basic programming constructs like loops, conditionals, and variable expansion.
Most modern shells—including bash, ksh, and zsh—are backward-compatible descendants of the Bourne shell, inheriting its syntax and behavior. You can write a simple script: #!/bin/sh followed by echo "Hello" to invoke it.
On modern Linux systems, /bin/sh typically points to bash or another POSIX-compliant shell rather than the original Bourne shell, but scripts written for the Bourne shell's features remain compatible due to standardization efforts like POSIX.