~/.ssh/config 配置格式

Host server1
　　HostName server1.cyberciti.biz
　　User nixcraft
　　Port 4242
　　IdentityFile /nfs/shared/users/nixcraft/keys/server1/id_rsa

如：

Host aliyun
　　HostName 123.123.123.123
　　User root
　　Port 22
　　IdentityFile /Users/ruby/.ssh/id_rsa