A useful thing that some distros have started doing is setting the color of your shell prompt differently if you're logged in as root. This gives you an additional visual cue that helps avoid doing ...

A vulnerability in the Linux sudo command has been discovered that could allow unprivileged users to execute commands as root. Thankfully, this vulnerability only works in non-standard configurations ...

The 'sudo' keyword in Unix and Linux allows users to execute certain commands with special-access privileges that cannot otherwise run on a given machine by a user with a lower level of clearance.