前提：已安装git。

1、输入以下命令生成ssh key，一路回车即可。（xxxx@xxx.com为你注册GitHub的邮箱）（注意，Gitee只需这一步，然后复制密码就好）

GitHub：ssh-keygen -t rsa -C "xxxx@xxx.com"

Gitee：ssh-keygen -t ed25519 -C "xxxx@xxx.com"

$ ssh-keygen -t rsa -C  "xxxx@xxx.com"
Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/Administrator/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /c/Users/Administrator/.ssh/id_rsa
Your public key has been saved in /c/Users/Administrator/.ssh/id_rsa.pub
The key fingerprint is:
SHA256:/ydX+AEdhH+HOukbM2knJNHjaa+vPhctxE70hDJv4ys  "xxxx@xxx.com"
The key's randomart image is:
+---[RSA 3072]----+
|              oo |
|           .o.o..|
|          . o*o+.|
|           o +Oo+|
|        S . =O.+o|
|         . ++o*.o|
|          ..B.o*.|
|           oEB= .|
|           .*@.  |
+----[SHA256]-----+

2、输入命令：eval "ssh-agent -s"

$ eval "ssh-agent -s"
SSH_AUTH_SOCK=/tmp/ssh-pdrfl8Q4DvbK/agent.585; export SSH_AUTH_SOCK;
SSH_AGENT_PID=586; export SSH_AGENT_PID;
echo Agent pid 586;

3、继续输入命令：ssh-add ~/.ssh/id_rsa

$ ssh-add ~/.ssh/id_rsa
Identity added: /c/Users/Administrator/.ssh/id_rsa (xxxx@xxx.com)

如果报错（Could not open a connection to your authentication agent.），则需要先执行命令：ssh-agent bash，再执行上述命令

4、复制生成的key到GitHub

查看key：cat ~/.ssh/id_rsa.pub（Gitee：$ cat .ssh/id_ed25519.pub）

$ cat ~/.ssh/id_rsa.pub
ssh-rsa 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 "xxxx@xxx.com"

GitHub位置如下：

5、检查是否成功：

ssh -T "git@github.com" （Gitee：ssh -T git@gitee.com）

GitHub的连不上，Gitee倒是连上了

$ ssh -T git@gitee.com
The authenticity of host 'gitee.com (212.64.63.215)' can't be established.
ED25519 key fingerprint is SHA256:+ULzij2u99B9eWYFTw1Q4ErYG/aepHLbu96PAUCoV88.
This key is not known by any other names
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'gitee.com' (ED25519) to the list of known hosts.
Hi mikasama! You've successfully authenticated, but GITEE.COM does not provide shell access.