Users and sudo

Many users, one computer

• Linux was built for many people to share one machine safely.
• Each person has a user account. whoami tells you who you currently are:

whoami

• Your files are yours; other users cannot read or change them unless you allow it.

The superuser: root

• One special user, root, can do anything — change any file, install software, manage other users.
• With great power comes great danger: a wrong command as root can break the whole system.
• So you normally work as an ordinary user, and only become root when you must.

sudo — borrow root for one command

• sudo runs a single command as root (it asks for your password first):

sudo apt install git

• Think of it as "do this super-user do". Use it only when a task truly needs admin rights — and read the command twice before you press Enter.