I have some .bdc files which I run on babylon dictionary on windows. but I can't run them on Goldendict (I have to say I run .bgl on Goldendict). Is there any other dictionary on Ubuntu to run .bdc files or Is there any way to convert .bdc to .BGL?
Same question here https://superuser.com/questions/852663/using-bdc-files-in-goldendict/1315601
The project https://github.com/ilius/pyglossary tried to do that conversion but the developer seems to have abandoned the idea
BDC files are encrypted and proprietary files so it's even illegal to convert them
What i advice you is to search google with the file you want to convert and add bgl to your search request, you will probably find what you look for because most dictionary are old and they have been in bgl format before being distributed as bdc
Also there is a huge catalog of free bdc dic on http://www.babylon-software.com/free-dictionaries i guess you will find most of your bdc there in bgl format.
Use pyglossary -- I think that tool might be able to convert BDC to BGL.