Find all running processes of a program

Find the pids of all instances/processes of a given program running on your system

Open a terminal and enter ps ax | grep "firefox" ...replacing 'firefox' with the name of the program you are looking for.

The columns in the output are as follows: (1) pid 'process id' (2) tty (3) process state - see man ps (4) process runtime (5) process command.