python3 script that takes a bib file and outputs a new bibfile with the DOIs it finds. I'm not using bibtool or taking any aux files. The requirements are bibtexparser and unidecode. This is based on : http://tex.stackexchange.com/questions/6810/automatically-adding-doi-fields-to-a-hand-made-bibliography/300474#300474
You can use it as such :
python3 searchdoi.py test.bib
And it will look like this :
Reading Bibliography...
Looking for Dois...
161/162 entries processed, please wait...
We added 49 DOIs !
Before: 42/162 entries had DOI
Now: 91/162 entries have DOI
Writing result to test.bib_doi.bib
You can now just check test.bib_doi.bib.