set up zsh to use gpg to sign commits for github

gpg-zsh.md

# Install GnuPG
% brew install gnupg
% gpg --full-generate-key
# RSA and DSA/4096 bytes/Never expires
# enter name
# noreply from emails settings in gh if anon commits, otherwise primary email
# empty comment
# secure passphrase
# bang on keyboard to randomize key
# output will be:
# -------------------------------------
# sec   rsa4096/AAAABBBBCCCCDDDD 2020-01-01 [SC]
#      096D86C5034E2DB9543C40BFB53551D684FCD7C4
# uid                 [ultimate] Your Name <12345678+gh-user@users.noreply.github.com>
# ssb   rsa4096/EEEEFFFF00001111 2020-01-01 [E]
# export command with key from 'sec' line after 'rsa4096/'
% gpg --armor --export AAAABBBBCCCCDDDD
# -----BEGIN PGP PUBLIC KEY BLOCK-----
# husxjijsijJIJ762378 etc.
# -----END PGP PUBLIC KEY BLOCK-----
# copy all including the ----- tags
# go to settings ssh and gpg keys in gh
# paste into a new gpg key there!
# return to terminal
% git config --global commit.gpgsign true
% git config --global user.signingkey AAAABBBBCCCCDDDD # same thing as used in above gpg --export statement
% echo 'export GPG_TTY=$(tty)' >> ~/.zprofile # add export to ~/.zprofile
% . ~/.zprofile # reload profile
# now go and change some stuff in a repo. when you commit...
% git commit -S -m 'Change Message.' # note using new flag -S which indicates "Secure"
# go to gh commits for that branch and see new "Verified" box appear next to your username for that commit in the commit list!!!