Shell A shell is a command line interpreter, forked off by the login program. After initializing itself, the shell types a prompt and waits for the user commands. The standard shell is sh or Bourne shell. There are also many others. Pipe A pipe connects two processes so that the output of one can be used as the input to the other.
Pipes are available on many operating systems.
Getting out Listing Files and Directories. Creating and Removing a Directory. Copying, Moving, and Renaming Files. Other Commands Remote login Use the command rlogin for logging onto a computer when you're not sitting at its console. UNIX is a multi-user system, which means more than one user can log on to a machine.