The Linux IPC (Inter-process communication) facilities provide a method for multiple processes to communicate with one another.

five types of interprocess communication:
n Shared memory permits processes to communicate by simply reading and writing to a specified memory location.
n Mapped memory is similar to shared memory, except that it is associated with a file in the filesystem.
n Pipes permit sequential communication from one process to a related process.
n FIFOs are similar to pipes, except that unrelated processes can communicate because the pipe is given a name in the filesystem.
n Sockets support communication between unrelated processes even on different computers.