ssh的密钥登录

ssh登录输入密码很麻烦，以前我是写一个expect脚本来登录，不过那比较土，安全的做法是用公钥、私钥的方法，参考这篇文章

   1.

      On the client run the following commands:

      $ mkdir -p $HOME/.ssh
      $ chmod 0700 $HOME/.ssh
      $ ssh-keygen -t dsa -f $HOME/.ssh/id_dsa -P ''

      This should result in two files, $HOME/.ssh/id_dsa (private key) and $HOME/.ssh/id_dsa.pub (public key).
   2.

      Copy $HOME/.ssh/id_dsa.pub to the server.
   3.

      On the server run the following commands:

      $ cat id_dsa.pub >> $HOME/.ssh/authorized_keys2
      $ chmod 0600 $HOME/.ssh/authorized_keys2

      Depending on the version of OpenSSH the following commands may also be required:

      $ cat id_dsa.pub >> $HOME/.ssh/authorized_keys
      $ chmod 0600 $HOME/.ssh/authorized_keys

      An alternative is to create a link from authorized_keys2 to authorized_keys:

      $ cd $HOME/.ssh && ln -s authorized_keys2 authorized_keys

   4.

      On the client test the results by ssh'ing to the server:

      $ ssh -i $HOME/.ssh/id_dsa server

   5.

      (Optional) Add the following $HOME/.ssh/config on the client:

      Host server
               IdentityFile ~/.ssh/id_dsa

      This allows ssh access to the server without having to specify the path to the id_dsa file as an argument to ssh each time.