If you go to the wwPDB ftp site https://ftp.wwpdb.org/ in your browser you can find the biological unit structures (and anything else available in the PDB). The caveat of course is that a biounit structure has to have been generated for your structure.
By way of some examples, to get all biological units you could do (note the
ftp instead of
https in front of the URL):
or to get a version organized in directories:
Note that this would take a few days to download everything, though. After the first download, you can add a
-N to the
wget command to just download new files.
For getting just one file:
Hope this helps.