Access other ttys

Linux normally has multiple terminals (ttys) running. You can switch between the different terminal sessions using keyboard shortcut. It's essentially the old-school version of having multiple terminal windows open.

In the world of desktop Linux, the login screen and the main desktop are usually run in terminals #1 and #2 respectively. This leaves terminals 3-6 free to still be used. You can use this to recover your system in the event of the desktop not starting, etc.