Linux processes

To find a process

Use pgrep command. pgrep looks through the currently running processes and lists the process IDs which matches the selection criteria to screen. For example display firefox process id:
# pgrep firefox
Sample outputs:

3356

or

# pidof firefox

3356  

Following command will list the process called sshd which is owned by a user called root:
$ pgrep -u root sshd


# ps 3356
Sample outputs:

PID   TTY  STAT   TIME   COMMAND

3356  ?    ..     ..     /path/to/executable

pstree shows running processes as a tree.  If a user name is specified, all process trees rooted at processes owned by that user are shown.
$ pstree

ps -u user  will show all processes of the user "user"
 $ ps -u user