pgrep: grep of processes

pgrep searches in the currently running processes for processes that match the search criterion passed as the argument.
For e.g. If we want to view all the processes that are being run by user1 we can use pgrep with the option -u i.e.

pgrep -u user1

This will the pids of all the processes being run by user1. To list the pid as well as the process name add the option "-l". i.e.

pgrep -l -u user1