Assumptions:

• You have fprintd installed already, following the Arch wiki.
• You have enrolled your fingerprints.

Install polkit:

sudo pacman -S polkit

Create a polkit-1 file in pam.d:

sudo nano /etc/pam.d/polkit-1

#%PAM-1.0
auth       sufficient   pam_fprintd.so
auth       include      system-auth
account    include      system-auth
password   include      system-auth
session    include      system-auth

Testing:

pkexec whoami

You should see the system authentication prompt and it should prompt for your fingerprint as well.

To Bitwarden:

In Settings -> Security, check “Unlock with system authentication”. Then close the settings and lock the vault with either the menu item or Ctrl+L.

The following are my random thoughts during setting up NixOS. I already have Manjaro installations boiled down into a set of shell scripts that let me reinstall and configure the OS fairly quickly and repeatably. NixOS solves this in a much nicer way, so that appealed. The ability to rollback a bad configuration or update was also a big draw.

Rolling back doesn’t revert the broken configuration.nix, so should I make /etc/nixos a git repo?