NOTE: I cannot offer support for this script. I got some reports from users that it does not work correctly in some situations, especially in Xcode 6 (please check the Issues).
Shell script to automatically extract translatable strings from Xcode storyboards and update .strings files. Original version by MacRumors forum user mikezang. Slightly updated by Ole Begemann.
See my accompanying blog post for details and usage instructions.
Until August 2014, this script lived as a Gist at https://gist.github.com/ole/5007019. Please refer to that page for earlier issues and comments.