By now, we've already used sudo quite a few times in this book. At this point, you should already be aware of the fact that sudo allows you to execute commands as if you were logged in as root. However, we haven't had any formal discussion about it, yet nor have we discussed how to actually modify which of your user accounts are able to utilize sudo.
On all Linux systems, you should protect your root account with a strong password and limit it to be used by as few people as possible. Using sudo is an alternative to using root, so you can give your administrators access to perform root tasks with sudo without actually giving them your root password. In fact, sudo allows you to be a bit more granular. Using root is basically all or nothing—if someone knows the root password and the root account is enabled, that person is not limited and can do whatever they want. With sudo, that can also be true, but you can actually restrict some users to use only...