SSH免密码登录

一、原理

使用公钥登录服务器，而非密码

二、使用命令

ssh-keygen：生成密钥对(一路回车),执行结果如下：

Generating public/private rsa key pair.
Enter file in which to save the key (/home/test/.ssh/id_rsa):
Created directory '/home/test/.ssh'.
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/test/.ssh/id_rsa.
Your public key has been saved in /home/test/.ssh/id_rsa.pub.
The key fingerprint is:
c4:d0:12:79:bb:4b:f3:b9:2a:6b:9f:a0:8c:b7:35:40 test@localhost

将会在默认目录（当前用户家目录的.ssh目录）生成密钥对（公钥：id_rsa.pub，私钥：id_rsa）

ssh-copy-id -i ~/.ssh/id_rsa test@192.168.1.2 ：将公钥复制到远程服务器，写入授权列表文件

The authenticity of host '192.168.1.2 (192.168.1.2)' can't be established.
RSA key fingerprint is b3:01:50:26:e0:3f:33:dc:63:a2:7b:3e:46:03:46:bd.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.1.2' (RSA) to the list of known hosts.
test@192.168.1.2's password:
Now try logging into the machine, with "ssh '192.168.1.2'", and check in:

.ssh/authorized_keys

to make sure we haven't added extra keys that you weren't expecting.

第一次需要输入密码，密码认证成功后，将会把本地服务器的id_rsa.pub内容添加到远程服务器的authorized_keys文件中。

三、应用

ssh -i ~/.ssh/id_rsa -p 1234 test@192.168.1.2 "ls -al"
scp -i ~/.ssh/id_rsa -P 1234 uploadFile test@192.168.1.2:/home/test/dir

01：使用ssh命令登录到远程服务器执行指定的命令，远程服务器的端口为1234，如果为默认的22，则无需指定。

02：使用scp命令拷贝文件到远程服务器的指定目录，远程服务器的端口为1234，如果为默认的22，则无需指定。