The hsklogin script uses the macOS ssh-agent with the yubikey, so that you don't have to type in the PIN for every git pull.

Set up your yubikey for github SSH and test that it works correctly.

git clone https://github.com/mrszymon/hsk
cd hsk
sudo cp hsklogin /usr/local/bin
chmod u+x /usr/local/bin/hsklogin

hsklogin -h

You will be prompted for your yubikey PIN:

• if keys are not installed
• if installed keys have expired
• following a reboot

hsklogin can be executed multiple times. Keys are replaced on each execution.

The script performs the following steps:

• ssh-add -e /usr/local/lib/libykcs11.dylib
  • removes any existing keys, with a specified duration (in seconds)
• ssh-add -s /usr/local/lib/libykcs11.dylib -t $life
  • prompts for your Yubikey PIN
  • adds Yubikey keys
• ssh-add -l
  • lists the installed keys

For more information, see man ssh-add.