Learning grep and awk is good, but not always necessory for getting information about logged in users.
You can simply use "who" or "w" commands to get the list of users currently logged in to the system.
Meanwhile, grep and awk both are filters, and used to manipulate the output of some command. Grep is normally used to filter some "keyword" from stream of data, whereas awk is a multi-function interpreter launguage, commonly used to cut field (columns) of some data stream.
Last edited by shivaa; 10-15-2012 at 01:16 PM.