1.打开Git Bash命令行窗口

2.检查是否已有SSH

如果没有，会返回如下信息，继续第三步创建SSH

    $ cd ~/.ssh
    bash: cd: /c/Users/Him/.ssh: No such file or directory

如果本地已经有创建SSH，会返回如下信息，表示本地已经有创建过SSH了，跳过第三步，直接看第四步

    $ cd ~/.ssh
     
    $ ls
    id_rsa  id_rsa.pub  known_hosts

3.创建SSH key

最后一个参数替换成你自己的GitHub注册邮箱

    $ ssh-keygen -t rsa -C "your_email@example.com"
    Generating public/private rsa key pair.

接下来会提示你输入生成的key存放的路径，不设置直接回车的话会默认创建在C:/Users/你的用户账号/.ssh文件夹下

    Enter file in which to save the key (/c/Users/Him/.ssh/id_rsa):
    Created directory '/c/Users/userpath/.ssh'.

再接下来会提示你输入密码，这个密码是用来每次提交的时候输入确认，可以不设置，直接回车两次

    Enter passphrase (empty for no passphrase):
    Enter same passphrase again:

最后成功后会看到类似如下的输出，表示成功生成SSH key了，可以到C:/Users/你的用户账号/.ssh文件夹下看下

    Your identification has been saved in /c/Users/Him/.ssh/id_rsa.
    Your public key has been saved in /c/Users/Him/.ssh/id_rsa.pub.
    The key fingerprint is:
    SHA256:RwvBINgH8CEt2KniltmykeyDsOseUYcwMzehFeyT86s 1225723686@qq.com
    The key's randomart image is:
    +---[RSA 2048]----+
    | o+%OO+o.        |
    |..=+%*+ ..       |
    | ..+o+o.. .      |
    |o.  o=.  o .     |
    |o oolalala S o      |
    | +.+.. . .       |
    |. .o    .        |
    |  . .  .         |
    |   . E.          |
    +----[SHA256]-----+

4.添加SSH key到GitHub

首先复制.ssh文件夹下id_rsa.pub文件的内容，可以直接用文本编辑器打开复制，也可以用如下命令行复制

    $ clip < ~/.ssh/id_rsa.pub

然后进入https://github.com/settings/keys设置，如果没有登录要先登录

或者登录后依次点击右上角Settings，然后再点击SSH and GPG keys

然后点击New SSH key按钮，然后输入Title和我们刚才复制的Key，Title的话表示这个key来自哪里，比如说可以叫“家里的笔记本”

最后点击Add SSH key按钮保存

5.测试SSH连接

输入如下命令

    $ ssh -T git@github.com

会得到如下输出，询问是否确认连接，输入yes回车确认

    The authenticity of host 'github.com (13.229.188.59)' can't be established.
    RSA key fingerprint is SHA256:nThbg6kXUpJWGl7mykeyCspRomTxdCARLviKw6E5SY8.
    Are you sure you want to continue connecting (yes/no)? yes

最后连接成功会看到如下输出

    Warning: Permanently added 'github.com,13.229.188.59' (RSA) to the list of known hosts.
    Hi ghxiaoxiao! You've successfully authenticated, but GitHub does not provide shell access.

参考
Connecting to GitHub with SSH