echo "foo hold" | dpkg --set-selections 
  -- place package "foo" on hold, i.e. don't upgrade this package, even if it means holding back loads of 
     upgrades that depend on the upgraded version. This is the same as Synaptic's "Package->Lock Version" 

     Note that apt-get dist-upgrade will override this, but will warn you first. Also, if you want to use 
     this with sudo, you need 
       'echo "foo hold" | sudo dpkg --set-selections' 
     and not 
       'sudo echo "foo hold" | dpkg --set-selections'