Previous chapters covered aspects of the GUI and the Shell. The third built- in Amiga interface is ARexx.
Like the Shell, ARexx is a text-based facility for giving commands to the Amiga, but while the Shell operates externally to programs (copy, delete, etc.), ARexx can operate internally with programs.
ARexx has two main uses: as a scripting lanauguage and for Inter-Process Communication (IPC). With the latter, ARexx acts as the standard hub for programs to communicate with each other by sending command and data messages.