Command Interpreter is the interface between
the user and the operating System. It is
usually separate from the kernel because it
treat the command interpreter as a special
program that is running when a job is
initiated or when a user first logs on the time
sharing systems.
Many Commands are given to the OS by
control statements, when a new job is started
in a batch system, or when a user logs on to a
time shared system. The program that reads
and interprets control statements is executed
automatically.