Good stuff but I just want to say .. IOTA seeds are not 12+ words. They are 81 characters, only A-Z and the number 9.

Methods to generate such a seed are as follows:

Linux 
cat /dev/urandom |tr -dc A-Z9|head -c${1:-81} 

Mac 
cat /dev/urandom |LC_ALL=C tr -dc 'A-Z9' | fold -w 81 | head -n 1