一、检查SSH key是否存在
在终端输入：
ls -al ~/.ssh
如果没有，终端显示如下：
No such file or directory
如果已经存在，则会显示id_rsa和id_rsa.pub
二、生成新的SSH key
在终端输入：
ssh-keygen -t rsa -C "[email protected]"
其中[email protected]为你在Github注册时的邮箱
成功后终端显示如下：
Generating public/private rsa key pair.
Enter file in which to save the key (/Users/xxx/.ssh/id_rsa):
提示你保存.ssh/id_rsa的路径，这里直接enter
Created directory '/Users/xxx/.ssh'.
Enter passphrase (empty for no passphrase):
提示输入passphrase，每次与Github通信都会要求输入passphrase，以避免某些“失误”，建议输入
成功后终端显示：
Your identification has been saved in /Users/xxx/.ssh/id_rsa.
Your public key has been saved in /Users/xxx/.ssh/id_rsa.pub.
The key fingerprint is:
16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48 [email protected]
The key's randomart image is:（后面图形省略）
三、添加key到SSH
输入命令：
ssh-add ~/.ssh/id_rsa
此时会要求输入passphrase，输入步骤二中填的passphrase
成功后，终端显示：
Identity added: /Users/xxx/.ssh/id_rsa (/Users/xxx/.ssh/id_rsa)
最后，在/Users/xxx/.ssh/生成两个文件，id_rsa和id_rsa.pub
此时，SSH key已经生成成功
四、添加SSH key到Github
1.复制id_rsa.pub中的所有内容
打开id_rsa.pub，终端命令：
vim ~/.ssh/id_rsa.pub
手动复制以ssh-rsa到以[email protected]结尾的所有内容
或者直接输入命令复制id_rsa.pub中的所有内容，终端命令：
pbcopy < ~/.ssh/id_rsa.pub
2.登录Github
打开个人Settings-->SSH keys-->Add SSH key
Title 随便写
Key 粘贴之前复制的内容
这样SSH key就添加的Github
五、检测SSH key
输入命令：
此时会验证SSH key是否可以访问Gitbub
成功显示如下：
Hi your_name! You've successfully authenticated, but GitHub does not provide shell access.
Connection to github.com closed.