以 ssh-key 代替密碼登入遠端機器

muchu@glory:~$ ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/muchu/.ssh/id_rsa): /home/muchu/id_rsa
Enter passphrase (empty for no passphrase): #直接按 enter
Enter same passphrase again: #直接按 enter
Your identification has been saved in /home/muchu/id_rsa.
Your public key has been saved in /home/muchu/id_rsa.pub.
The key fingerprint is:
21:02:7e:b1:7d:11:85:26:e7:4b:16:ae:39:d5:79:ed muchu@glory
The key's randomart image is:
+--[ RSA 2048]----+
| . . o+. |
| . . +. =. |
| . + o*oo . . |
| . . o*.o . . |
| *S. . . |
| + . E |
| . |
| |
| |
+-----------------+
muchu@glory:~$ ls /home/muchu | grep id_rsa
id_rsa id_rsa.pub

id_rsa 是私錀，id_rsa.pub 是公錀。
將 "公錀的內容" 附加在 "對方" 主機的 ~/.ssh/authorized_keys 下。
並將私錀以 id_rsa 的名稱放在 ~/.ssh/ 下。就可以不用密碼 ssh 登入 "對方" 主機。

在 debian 系統，放公錀到對方主機的動作可以透過以下命令完成，先將公錀放在 ~/.ssh/ 下
ssh-copy-id muchu@www