How to avoid being asked "Enter passphrase for key ..." when doing git operations

• Start the ssh-agent in the background.

$ eval "$(ssh-agent -s)"
Agent pid 78736

• If you’re using macOS Sierra 10.12.2 or later, you will need to modify your ~/.ssh/config file to automatically load keys into the ssh-agent and store passphrases in your keychain.

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

• Add your SSH private key to the ssh-agent and store your passphrase in the keychain.

$ ssh-add -K ~/.ssh/id_rsa

• And now you can try to connect to your git server.

$ ssh git.example.com

Maybe you should change ~/.ssh/id_rsa to your private key file.

You can find more details on this page : Adding ssh key to the ssh-agent