brew install gpg.
Follow the GitHub guide to generate a new gpg key.
Add the gpg key to your GitHub account.
Get around this issue by doing the following
echo 'export GPG_TTY=$(tty)' >> ~/.bash_profile
Test that gpg works through
echo "test" | gpg --clearsign
(Optional) If you want to enable signing on every commit
git config --global commit.gpgsign true
Test a commit. You need to provide the
-Sflag if you didn't do step 7:
git commit -S -m "This is a signed commit"