In computer science, an anonymous pipe is a simplex FIFO communication channel that may be used for one-way interprocess communication (IPC). An implementation is often integrated into the operating system's file IO subsystem. Typically a parent program opens anonymous pipes, and creates a new process that inherits the other ends of the pipes, or creates several new processes and arranges them in a pipeline.
Full-duplex (two-way) communication normally requires two anonymous pipes.
Pipelines are supported in most popular operating systems, from Unix and DOS onwards, and are created using the "|" character in many shells.