git ssh-add 报错 ssh-add Could not open a connection to your authentication agent

$ ssh-add ~/.ssh/id_rsa.pub
Could not open a connection to your authentication agent.

启动ssh-agent服务

eval `ssh-agent -s`

再运行

$ ssh-add
Identity added: /c/Users/name/.ssh/id_rsa (/c/Users/name/.ssh/id_rsa)

参考链接：http://stackoverflow.com/questions/17846529/could-not-open-a-connection-to-your-authentication-agent