ssh without password

我们经常通过ssh访问服务器，每一次都要输入密码，为了避免这一环节，我们进行一下操作：
1、输入：

ssh-keygen -t rsa

这样你的~/.ssh/目录中就有两个新文件了，id_rsa和id_rsa.pub,分别为private/public key；

[eva@Eva ~]$ ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/eva/.ssh/id_rsa): 
/home/eva/.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 /home/eva/.ssh/id_rsa.
Your public key has been saved in /home/eva/.ssh/id_rsa.pub.
The key fingerprint is:
f6:b1:f1:38:8c:41:31:c6:53:01:7f:7d:53:d9:4e:c7 eva@Eva
The key's randomart image is:
+--[ RSA 2048]----+
|       .=oo.   .+|
|       .o+   . .E|
|        ... . .+o|
|       .   .   .o|
|        S o      |
|       . = *     |
|        . * .    |
|           .     |
|                 |
+-----------------+
[eva@Eva ~]$ cd /home/eva/.ssh
[eva@Eva .ssh]$ ls
id_rsa  id_rsa.pub

注意：每次执行"ssh-keygen -t rsa"产生的私钥文件都会不同
2、把public key拷贝到服务器上，放在~/.ssh/目录中，首先登陆服务器，看看有没有该目录，没有就新建一个：

ssh [e-mail]
mkdir ~/.ssh

把刚才生成的public key文件拷贝到服务器上

scp ~/.ssh/id_rsa.pub [e-mail]:~/.ssh/

3、在服务器上把刚传过来的id_rsa.pub累加到authorized_keys文件末尾

ssh [e-mail]
cd ~/.ssh
cat id_rsa.pub >> authorized_keys

密钥不是人人可读的，所以要设置一下权限：

chmod 700 ~/.ssh
chmod 600 ~/.ssh/authorized_keys

4、每次登陆都需要输入[e-mail]是不是很烦，下面做一个alias就可以了：

echo 'alias sshsss="ssh [e-mail]"' >> .bashrc
source .bashrc
sshsss