ssh无密码登录

>ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (~/.ssh/id_rsa):
~/.ssh/id_rsa already exists.
Overwrite (y/n)? y
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in ~/.ssh/id_rsa.
Your public key has been saved in ~/.ssh/id_rsa.pub.
The key fingerprint is:
03:5f:cd:46:00:53:85:f4:1d:b7:b7:5f:cd:56:43:5b cbs@localhost
The key's randomart image is:
+--[ RSA 2048]----+
|        o+++o ..E|
|         ..= ..o+|
|      .   . = .+o|
|       o . .   .*|
|        S      .=|
|         .     .o|
|                .|
|                 |
|                 |
+-----------------+

ssh user@host "cat >>~/.ssh/authorized_keys" < ~/.ssh/id_rsa.pub