转载：https://my.oschina.net/lieefu/blog/469337
ssh链接git服务器，解决Agent admitted failure to sign using，错误信息如下：
Agent admitted failure to sign using the key.
git@git.oschina.net's password:
Permission denied, please try again.
git@git.oschina.net's password:
Permission denied, please try again.
git@git.oschina.net's password:
Permission denied (publickey,password,keyboard-interactive).
fatal: Could not read from remote repository.
原因是ssh-agent服务没把新产生的/home/you/.ssh/id_rsa 包含进去，解决方法如下：
start the ssh-agent in the background
eval "$(ssh-agent -s)"
Agent pid 59566
ssh-add
Enter passphrase for /home/you/.ssh/id_rsa: [tippy tap]
Identity added: /home/you/.ssh/id_rsa (/home/you/.ssh/id_rsa)
如果你的私钥文件已经改名，不是默认的id_rsa,请输入你的正确的私钥文件路径：
start the ssh-agent in the background
eval "$(ssh-agent -s)"
Agent pid 59566
ssh-add ~/.ssh/my_other_key
