I'm restarting (and updating) the Gem of the Week Series 
that highlights a new ruby library every week on Thursdays.
Let's welcome the hexapdf gem / library and command line tools [2a][2b] -
read and write PDF documents; start from zero or merge, extract,
optimize and much more.
Thanks to Thomas Leitner for the write-up (and the great gem).
Happy coding with ruby. Cheers. Prost.