Most common system shell in Unix/Linux environments. Integrates very well with other softwares having a command line interface. Widely used in CI scripts and buildscripts.
The shell is developed since 1988 by the Free Software Foundation.
In the decades, it has got most features of a high-level programming language, including exception handling, high-level data structures inculding dictionary and arrays, while it still preserved its close connection to the low-level OS functionality.
Its main purpose in the CI/DevOps world is to integrate the command-line interfaces of different softwares to each other.