Network, Computer and Programming Resources

Linux top 50 cmd - Su

su enables a user to temporarily become another user. If a user ID is not given, the computer thinks you want to be the superuser, or root. In either case, a shell is spawned that makes you the new user, complete with that user ID, group ID, and any supplemental groups of that new user. If you are not root and the user has a password (and the user should!), su prompts for a password. Root can become any user at any time without knowing passwords. Technically, the user just needs to have a user ID of 0 (which makes a user a superuser) to log on as anyone else without a password.