The ps command with the -o etime or etimes option can be used to display how long a process has been running for (elapsed time).

• etime will display elapsed time in the mm:ss format
• etimes will display how many seconds a process has been running

In this example, the process associated with process ID number (PID) 12345 has been running for 20 seconds.

~]$ ps -p 12345 -o etime
    ELAPSED
      00:20

Often, you will want to know more about the process. The command option can be included to get an idea of what command the process is associated with.

~]$ ps -p 12345 -o etime,command
    ELAPSED COMMAND
      00:20 /usr/bin/foo