The C shell, often abbreviated as Csh, is a Unix shell that provides an interface for users to interact with the operating system. It was developed by Bill Joy in the late 1970s and is known for its C-like syntax, which makes it easier for programmers familiar with the C programming language to use. The C shell supports features like command history, job control, and aliases, enhancing user productivity. C shell scripts can automate tasks and are commonly used for system administration and software development. While it has been popular, other shells like Bash and Zsh have gained favor due to their additional features and improved performance.