dash (short for Debian Almquist shell) is a Unix shell that is commonly used as the default /bin/sh interpreter on many Linux distributions, including Debian, Ubuntu, and some others. It is designed to be a lightweight, fast, and POSIX-compliant alternative to the traditional bash shell.
dash is a POSIX-compliant shell, which means that it adheres to the POSIX standards for Unix shells. This makes dash a reliable and predictable shell for scripting, as it behaves in a consistent way across different platforms.
dash is smaller and faster than bash, as it does not include many of the features and functionality that are specific to bash. For example, dash does not support the built-in history command, or the advanced command line editing features of bash.
While dash is a good choice for use in scripts due to its simplicity and POSIX compliance, it may not be the best choice for interactive use, as it lacks many of the features and convenience functions that are available in bash.
In summary, dash is a fast and lightweight shell that is well-suited for use in scripts and other automated processes, while bash is a more feature-rich shell that is better suited for interactive use.