When you created your first user on your host, centos1 and centos2, you made them an administrator. This allowed them to (when they request it) run commands with root priveleges. But you won't always know in advance if a user is going to be an administrator (what if someone gets promoted, or changes jobs?), so you can't always do that in advance. Checking that box also allows them to run ''any'' command with root priveleges by using sudo. In many cases, administrators won't be allowed to do ''everything'', but instead be restricted to certain tasks (e.g. managing user accounts, managing software, managing services, etc.). Sudo will allow us this detailed control, so we can pick and choose who gets to run which commands as root.

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