Google authenticator

google authenticator is a 2 factor authentication program.
You can use it on linux to enable 2FA PAM logins.
You cannot use it to obtain keycodes (you'll need the ios/android app, or something like authy on a desktop)

Tutorials

Arch Wiki

https://wiki.archlinux.org/index.php/Google_Authenticator

Install

pacman -S libpam-google-authenticator

Usage

google-authenticator  # setup configuration