You can also list different information about each process. The --forest option makes it easy to see the process hierarchy, which will give you an indication of how the various processes on your system interrelate. When a process starts a new process, that new process is called a "child" process. In a --forest listing, parents appear on the left, and children appear as branches to the right:

$ ps x --forest
  PID TTY      STAT   TIME COMMAND
  927 pts/1    S      0:00 bash
 6690 pts/1    S      0:00  \_ bash
26909 pts/1    R      0:00      \_ ps x --forest
19930 pts/4    S      0:01 bash
25740 pts/4    S      0:04  \_ vi processes.txt