Shell

In computing, a shell is a user interface for access to an operating system's services. In general, operating system shells use either a command-line interface (CLI) or graphical user interface (GUI), depending on a computer's role and particular operation. It is named a shell because it is a layer around the operating system kernel.

OS/2 CONFIG.SYS statements

PROTSHELL - CONFIG.SYS command to define protected mode shell

Example: PROTSHELL=C:\OS2\PMSHELL.EXE

SHELL - CONFIG.SYS command to define DOS command interpreter

Example: SHELL=C:\OS2\MDOS\COMMAND.COM C:\OS2\MDOS /P

OS2_SHELL - Environment variable

Example: SET OS2_SHELL=C:\OS2\CMD.EXE