Fix for SSH passphrases on MacOS Sierra

Since updating to MacOS Sierra, GitHub asks me for my SSH passphrase every single time I try to pull or push.

The benefit of SSH over HTTPS is specifically that you don’t have to enter your credentials every time. From my research, this appears to be a change to how the MacOS keychain handles things in Sierra.

Fortunately, I also stumbled onto an easy fix from Josh Buchea:

1. In terminal, run cd ~/.ssh.
2. Next, run open . to open the .ssh directory.
3. In the config file, add the snippet below. If no config file exists, create one first.

Host *
  UseKeychain yes
  AddKeysToAgent yes
  IdentityFile ~/.ssh/id_rsa

This tells MacOS to use the credentials stored in your Keychain for SSH. If your token is named something other than id_rsa (the default), naturally you’ll want to change that in the snippet above.