Originally Posted By: hybrid8
So, would it be "-2 1" for the first field in the second file? And does it matter that the first file has more than just the one field per row?

Yes, and no respectively.

Quote:
join: invalid file number in field spec: `auto'

Oh dear, what does "join --version" say? Mine is 8.15. If you miss out the "-o auto" you'll get a less helpful (but probably still usable) output.

Peter