An integer used by the Unix kernel to uniquely identify a process. PIDs are returned by the fork system call and can be passed to wait() or kill() to perform actions on the given process.

Shown in the heading of the ps command as PID. The unique number assigned to every process running in the system.

(in UNIX) that is native to a machine or operating system.

See PID

A numerical identifier that uniquely distinguishes a process while it runs. Use Task Manager to view PIDs. See also: Task Manager; process

In computing, the process identifier (normally referred to as the process ID or just PID) is a number used by some operating system kernels (such as that of UNIX, Mac OS X or Windows NT) to uniquely identify a process.