Get multiple cursors (ctrl-d) working in atom on Ubuntu 14.04 LTS

1. Open your keymap file. Press ctrl-shift-p and type keymap. Select the option Application: Open Your Keymap

2. Now, add the following to keymap.cson

   '.editor':
     'ctrl-d': 'find-and-replace:select-next'

3. That's it!

Reference: https://github.com/atom/atom/issues/2002