title: How to permanently add a private key with ssh-add on Ubuntu?
body: <p>I have a private key protected with a password to access a server via SSH. </p>
  
  <p>I have 2 linux (ubuntu 10.04) machines and the behavior of ssh-add command is different in both of them. </p>
  
  <p>In one machine, once I use "ssh-add .ssh/identity" and entered my password, the key was added permanently, i.e., every time I shutdown the computer and login again, the key is already added.</p>
  
  <p>In the other one, I have to add the key every time I login. </p>
  
  <p>As far as I remember, I did the same thing on both. The only difference is that the key was created on the one that is added permanently.</p>
  
  <p>Does anyone know how to add it permanently to the other machine as well?</p>