tokens: This is a pretty obtuse answer , and definitely not a one-liner , but here is how it can be done in bash , with a little help from bc and tr ( works on osx ) :
ner_tags: O O O O O O O O O O O O O O O O O O O O O O B-Language O O O O O O B-Code_Block O B-Code_Block O O O B-Operating_System O O