1 如果没有安装ssh，那么使用下面的指令
sudo apt-get install ssh
2 检查SSH公钥
cd ~/.ssh
看看存不存在.ssh，如果存在的话，掠过下一步；不存在的请看下一步
3 生成SSH公钥
$ ssh-keygen -t rsa -C "your_email@youremail.com"
# Creates a new ssh key using the provided email Generating public/private rsa key pair.
Enter file in which to save the key (/home/you/.ssh/id_rsa):
现在你可以看到，在自己的目录下，有一个.ssh目录，说明成功了
3.1 输入github密码（留空按回车键）
Enter passphrase (empty for no passphrase): [Type a passphrase]
Enter same passphrase again: [Type passphrase again]
这个时候输入你在github上设置的密码。
3.2 然后在.ssh中可以看到
Your identification has been saved in /home/you/.ssh/id_rsa.
# Your public key has been saved in /home/you/.ssh/id_rsa.pub.
# The key fingerprint is:
# 01:0f:f4:3b:ca:85:d6:17:a1:7d:f0:68:9d:f0:a2:db your_email@youremail.com
4 添加SSH公钥到github
打开github，找到账户里面添加SSH，把idrsa.pub内容复制到key里面。
5 测试是否生效
使用下面的命令测试
ssh -T git@github.com
当你看到这些内容放入时候，直接yes
The authenticity of host 'github.com (207.97.227.239)' can't be established.
RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
Are you sure you want to continue connecting (yes/no)?
看到这个内容放入时候，说明就成功了。
Hi username!
You've successfully authenticated, but GitHub does not provide shell access.