ssh无需密码登录linux服务器使用下例中ssky-keygen和ssh-copy-id，仅需通过3个步骤的简单设置而无需输入密码就能登录远程Linux主机。ssh-keygen 创建公钥和密钥。ssh-copy-id 把本地主机的公钥复制到远程主机的authorized_keys文件上。ssh-copy-id 也会给远程主机的用户主目录（home）和~/.ssh, 和~/.ssh/authorized_keys设置合适的权限 。
步骤1: 用 ssh-key-gen 在本地主机上创建公钥和密钥
ligh@local-host$ ssh-keygen -t rsaEnter file in which to save the key (/home/jsmith/.ssh/id_rsa):[Enter key] Enter passphrase (empty for no passphrase): [PRess enter key]Enter same passphrase again: [Pess enter key]Your identification has been saved in /home/jsmith/.ssh/id_rsa.Your public key has been saved in /home/jsmith/.ssh/id_rsa.pub. The key fingerprint is: 33:b3:fe:af:95:95:18:11:31:d5:de:96:2f:f2:35:f9 ligh@local-host
步骤2: 用 ssh-copy-id 把公钥复制到远程主机上
ligh@local-host$ ssh-copy-id -i ~/.ssh/id_rsa.pub root@192.168.0.3ligh@remote-host‘s passWord:Now try logging into the machine, with ―ssh ?remote-host‘‖, and check in: .ssh/authorized_keys to make sure we haven‘t added extra keys that you weren‘t expecting.
[注: ssh-copy-id 把密钥追加到远程主机的 .ssh/authorized_key 上.]
ligh@local-host$ ssh remote-host Last login: Sun Nov 16 17:22:33 2008 from 192.168.1.2 ligh@remote-host$
[注: 你现在已经登录到了远程主机上]