$ ssh-add id_rsa_bitbucket
Could not open a connection to your authentication agent.
运行：
$ ssh-agent bash
然后：
$ ssh-add id_rsa_bitbucket
Identity added: id_rsa_bitbucket (id_rsa_bitbucket)
就ok了
Git Bash for Windows add ssh key时报Could not open a connection to your authentication agent.
原文：http://www.cnblogs.com/Joynic/p/6506090.html