I have tested it now on different machines and different distros - it all works fine, apart from:
Code:
Failed to initialize plugin: ISBNDB (1, 0, 0)
Failed to initialize plugin: <class 'calibre.ebooks.metadata.sources.isbndb.ISBNDB'>
but this doesn't seem to cause any problems?
I don't know if it has anything to do with the shell, or (more likely not?)
Would be nice if someone else could test it as well, but afaic it's a good one

thank you.