Note: “Sudo” is short for “Substitute User Do” or “Superuser Do”

This may come as a shock if you’re new to Mac and ever used a *nix system before.. but the sudo password, is your password! If you’re administrator anyway, if not, ask your *rents, instructor or local admin to help you out. 😉

/etc/sudoers contains the permissions for who can use it, and once you have it, it is very powerful indeed.

If for any reason you need to have access to the full root account, this is actually not enabled on a Mac by default, for good reason.

To Enable Root User (see Apple KB below for reference):
1) From the Apple menu choose System Preferences….
2) From the View menu choose Accounts.
3) Click on the lock and authenticate with an administrator account.
4) Click Login Options….
5) Click the “Edit…” or “Join…” button at the bottom right.
6) Click the “Open Directory Utility…” button.
7) Click the lock in the Directory Utility window.
8) Enter an administrator account name and password, then click OK.
9) Choose Enable Root User from the Edit menu.
10) Enter the root password you wish to use in both the Password and Verify fields, then click OK.

References
Apple KBase, http://support.apple.com/kb/ht1528
Wikipedia (Sudo), http://en.wikipedia.org/wiki/Sudo
Wikipedia (SU), http://en.wikipedia.org/wiki/Su_%28Unix%29