Replace the [username] with the required username
If you want to use ps then
ps -u [username]
OR
ps -ef | grep <username>
OR
ps -efl | grep <username>
Answers for everything
Replace the [username] with the required username
If you want to use ps then
ps -u [username]
OR
ps -ef | grep <username>
OR
ps -efl | grep <username>