If you are running OSX 10.6.8 or later you can skip this step. The OSX 10.6.8 system asks for your connection parameters the first time you try to establish a SSH connection. Then, it automatically starts the ssh-agent for you. If you don't have OSX 10.6.8 or are running another Linux operating system, do the following:
Open a terminal window and enter the ps -e | grep [s]sh-agent command to see if the agent is running:
myhost:~ manthony$ ps -e | grep [s]sh-agent
9060 ?? 0:00.28 /usr/bin/ssh-agent -l
If the agent isn't running, start it manually with the following command:
myhost:~ manthony$ ssh-agent /bin/bash
Load your new identity into the ssh-agent management program using the ssh-add command.
$ ssh-add ~/.ssh/id_rsa
Enter passphrase for /Users/manthony/.ssh/id_rsa:
Identity added: /Users/manthony/.ssh/id_rsa (/Users/manthony/.ssh/id_rsa)
myhost:~ manthony$
Use the ssh-add command to list the keys that the agent is managing.
$ ssh-add -l
2048 7a:9c:b2:9c:8e:4e:f4:af:de:70:77:b9:52:fd:44:97 /Users/manthony/.ssh/id_rsa (RSA)