csh:tldr:9726b

The command "csh" refers to the C shell, which is a Unix command-line interpreter or shell. It is a command processor that provides users with a way to interact with the underlying operating system.

When you run the "csh" command, it launches the C shell and presents you with a command prompt, where you can enter various commands to perform different tasks such as navigating the file system, executing programs, managing processes, setting environment variables, etc.

The C shell, often abbreviated as "csh," is one of the several available Unix shells, and it provides different features and syntax compared to other shells like the Bourne shell (sh), Bourne Again shell (bash), or Z shell (zsh). Each shell has its own set of commands, variables, and syntax, so the behavior and capabilities of "csh" may differ from other shells.

If you are familiar with the C shell or using a system that utilizes it as the default shell, running the "csh" command will open a new shell session where you can interact with the system.