Updated at 2022-05-08 04:47

TTY stands for "teletype". Also known to stand for "teletypewriter".

  • Teletypewriters are electromechanical devices that can send and receive messages down the wire. These devices were the way to use computers in mid 1900s.
  • The mechanical teletypewriters were replaced by virtual teletypewriters that emulated those machines using just electronics.
  • Nowadays, engineers mainly work through pseudo-teletypewriters which emulate the teletypewriters using software e.g. xterm.

This terminology is still used in modern Linux systems e.g. tty command prints the name of the terminal you are using.

$ tty
# means "pseudo-teletypewriter device number 1"

Linux servers are often configured without a graphical desktop environment, which means you don't have access to a mouse and other niceties.

Accessing a text-only TTY sessions is handy when your system freezes. You can switch between teletype sessions on your computer with Ctrl+Alt+<F-key>. These are virtual teletypewriters emulated in hardware; not pseudo-teletypewriters as your normal everyday terminals.

# the usual shortcuts on modern Linux distributions:
Ctrl+Alt+F1 = login screen
Ctrl+Alt+F2 = desktop when logged in
Ctrl+Alt+F3 = blank virtual terminal
Ctrl+Alt+F4 = blank virtual terminal
Ctrl+Alt+F5 = blank virtual terminal
Ctrl+Alt+F6 = blank virtual terminal