How to Use ssh-add to Avoid Typing Passphrase Over and Over Again

To avoid typing passphrase for a specific key over and over again, like when git pull from github, can use this command

ssh-add path/to/the/key

It will store the key as long as the session is live. Using ps command, we can see the process of /usr/bin/ssh-agent, the ssh-agent will handle passphrase for us.