Linux is a multi-user operating system. What does that mean? Like all good operating systems, you can have multiple user accounts on one machine. You can also have more than one user logged in at once ...

Linux, renowned for its robustness and security, is a powerful multi-user operating system that allows multiple people to interact with the same system resources without interfering with each other.

Sudo lets you run any terminal command as another user — hence "substitute user" — but the default and most common use for it ...