step1: gitlab

$ ssh-keygen -t rsa -C xxx.yy@zzz.com
Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/xxx/.ssh/id_rsa): id_rsa_gitlab
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in id_rsa_gitlab
Your public key has been saved in id_rsa_gitlab.pub

step2: github

$ ssh-keygen -t rsa -C xxx@163.com
Generating public/private rsa key pair.
Enter file in which to save the key (/c/Users/zzz/.ssh/id_rsa): id_rsa_github
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in id_rsa_github
Your public key has been saved in id_rsa_github.pub

step3: 将得到的id_rsa/id_rsa.pub文件保存在git默认访问的.ssh的目录；

$ ls
config  id_rsa_github  id_rsa_github.pub  id_rsa_gitlab  id_rsa_gitlab.pub  known_hosts  known_hosts.old

step4: 将github/gitlab的公钥分别上传到对应的服务器；

github：setting / SSH and GPG keys；

gitlab：setting / SSH keys

step5: 在.ssh目录创建config文本文件，完成对应的git配置；

每个账号单独配置一个Host，每个Host要取一个别名，每个Host主要配置HostName和IdentityFile两个属性即可

Host的名字可以取为自己喜欢的名字，不过这个会影响git相关命令，例如：
Host mygithub 这样定义的话，命令如下，即git@后面紧跟的名字改为mygithub；

HostName 　　　　　　　      这个是真实的域名地址
IdentityFile 　　　　　　　  这里是id_rsa的地址
PreferredAuthentications   配置登录时用什么权限认证--可设为publickey,password publickey,keyboard-interactive等
User 　　　　　　　　　　     配置使用用户名

example：git clone git@mygithub:happyamyhope/IPM.git

# GitLab.xxx.yy
Host gitlab.xxx.yy
    HostName gitlab.xxx.yy
    IdentityFile  C:\Users\zzz\.ssh\id_rsa_gitlab 
    RSAAuthentication yes
    PreferredAuthentications publickey
    User aaa.bbb@ccc.com
# Github.com
Host github.com
    HostName github.com
    IdentityFile /c/Users/zzz/.ssh/id_rsa_github
    RSAAuthentication yes
    PreferredAuthentications publickey
    User ddd@163.com

step6：测试；

$ ssh -T git@github.com
/c/Users/zzz/.ssh/config line 6: Unsupported option "rsaauthentication"
/c/Users/zzz/.ssh/config line 13: Unsupported option "rsaauthentication"
Enter passphrase for key '/c/Users/zzz/.ssh/id_rsa_github':
Hi happyamyhope! You've successfully authenticated, but GitHub does not provide shell access.

参考

1. Windows下Git多账号配置，同一电脑多个ssh-key的管理；

完