A PID (i.e., process identification number) is an identification number that is automatically assigned to each process when it is created on a Unix-like operating system.

A process is an executing (i.e., running) instance of a program.

Each process is guaranteed a unique PID, which is always a non-negative integer.

How do I find the PID of a process in Linux?

Procedure to find process by name on Linux

• Open the terminal application.
• Type the pidof command as follows to find PID for firefox process: pidof firefox.
• Or use the ps command along with grep command as follows: ps aux | grep -i firefox.
• To look up or signal processes based on name use:

What is PID in operating system?

In computing, the process identifier (normally referred to as the process ID or PID) is a number used by most operating system kernels—such as those of UNIX, macOS and Microsoft Windows—to uniquely identify an active process.