我有两个github帐号，一个是个人所用，一个是为公司项目所用。如果是单用户(single-user)，很方便，默认拿id_rsa与你的github服务器的公钥对比；如果是多用户（multi-user）如user1,user2,那么就不能用在user2的身上了，这个时候就要配置一下了：
1、新建user2的SSH Key
#新建SSH key：
$ cd ~/.ssh # 切换到C:\Users\Administrator\.ssh
ssh-keygen -t rsa -C "mywork@email.com" # 新建工作的SSH key
# 设置名称为id_rsa_work
Enter file in which to save the key (/c/Users/Administrator/.ssh/id_rsa): id_rsa_work
2、新密钥添加到SSH agent中
因为默认只读取id_rsa，为了让SSH识别新的私钥，需将其添加到SSH agent中：
ssh-add ~/.ssh/id_rsa_work
如果出现Could not open a connection to your authentication agent的错误，就试着用以下命令：
ssh-agent bash 或 ssh-ahent sh
ssh-add ~/.ssh/id_rsa_work
3、修改config文件
在~/.ssh目录下找到config文件，如果没有就创建：
touch config # 创建config
然后修改如下： 我的config配置如下：
Host github.com_camps
HostName github.com
User git
IdentityFile C:/Users/username/.ssh/id_rsa
Host github.com_mvc
HostName github.com
User git
IdentityFile C:/Users/username/.ssh/id_rsa_femvc
如果存在的话，其实就是往这个config中添加一个Host：
#建一个github别名，新建的帐号使用这个别名做克隆和更新
Host github.com_mvc
HostName github.com
User git
IdentityFile ~/.ssh/id_rsa_femvc
其规则就是：从上至下读取config的内容，在每个Host下寻找对应的私钥。这里将GitHub SSH仓库地址中的git@github.com替换成新建的Host别名如：github.com_mvc，那么原地址是：
git@github.com:funpeng/Mywork.git
替换后应该是：
git@github.com_mvc:funpeng/Mywork.git
4、打开新生成的 ~/.ssh/id_rsa_femvc.pub 文件，将里面的内容添加到GitHub后台。
可不要忘了添加到你的另一个github帐号下的SSH Key中。
5、测试：
Administrator@FANGPENG /e/work
$ ssh -T git@github.com_camps
Hi fecamps! You've successfully authenticated, but GitHub does not provide shel
l access.
Administrator@FANGPENG /e/work
$ ssh -T git@github.com_mvc
Hi femvc! You've successfully authenticated, but GitHub does not provide shell access.
6、应用
测试成功，那么我尝试在我的work目录下克隆我账号下的远程仓库。如下：
username@WIN-8BNSQDEB70D:/C/baiduyun/fecampus $ git clone git@github.com_camps:fecamps/nodejs-text-db.git
Cloning into 'nodejs-text-db'...
remote: Counting objects: 9, done.
remote: Compressing objects: 100% (8/8), done.
remote: Total 9 (delta 1), reused 5 (delta 0)
Receiving objects: 100% (9/9), done.
Resolving deltas: 100% (1/1), done.
Checking connectivity... done.
username@WIN-8BNSQDEB70D:/C/baiduyun/fecampus/nodejs-text-db [master]$ git push
Counting objects: 3, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (2/2), done.
Writing objects: 100% (2/2), 225 bytes | 0 bytes/s, done.
Total 2 (delta 1), reused 0 (delta 0)
To git@github.com_camps:fecamps/nodejs-text-db.git
bd4be9d..f886fa8 master -> master
username@WIN-8BNSQDEB70D:/C/baiduyun/fecampus $ git clone git@github.com_mvc:fe
mvc/HTMLParser.git
Cloning into 'HTMLParser'...
remote: Counting objects: 21, done.
remote: Total 21 (delta 0), reused 0 (delta 0)
Receiving objects: 100% (21/21), 6.56 KiB | 0 bytes/s, done.
Resolving deltas: 100% (8/8), done.
Checking connectivity... done.
username@WIN-8BNSQDEB70D:/C/baiduyun/fecampus/HTMLParser [master]$ git push
Counting objects: 3, done.
Delta compression using up to 2 threads.
Compressing objects: 100% (1/1), done.
Writing objects: 100% (2/2), 226 bytes | 0 bytes/s, done.
Total 2 (delta 1), reused 1 (delta 1)
To git@github.com_mvc:femvc/HTMLParser.git
e7149b6..ffca602 master -> master
克隆修改上传成功，大功告成了！