The year is 2009 and your minimalist CD ripper, let's say goobox hasn't multi-CD support. The ripped content of both CD 1 & 2 are numbered incrementally from 01 onwards, which isn't a problem if you organised your library by CD 1/2/etc, but you're rather flatten the directory because you used mongodb once.
The following is a shorthand for incrementing the numbers on disc 2 by 12:
perl-rename -n 's/(\d+)/($1 + 12)/e' *.ogg
The -n here makes it a dry run, which outputs the following for you to confirm:
01. Slave to Your Mind.ogg -> 13. Slave to Your Mind.ogg
02. Shortcut to Salvation.ogg -> 14. Shortcut to Salvation.ogg
03. The Man in the Iron Cage.ogg -> 15. The Man in the Iron Cage.ogg
04. The Road Called Home.ogg -> 16. The Road Called Home.ogg
05. Sloth.ogg -> 17. Sloth.ogg
06. Freedom Song.ogg -> 18. Freedom Song.ogg
07. I m Running.ogg -> 19. I m Running.ogg
08. The Mask.ogg -> 20. The Mask.ogg
09. Confrontation.ogg -> 21. Confrontation.ogg
10. The Battle.ogg -> 22. The Battle.ogg
11. Broken Sky Long Day (Reprise).ogg -> 23. Broken Sky Long Day (Reprise).ogg
Prima! Just drop the -n option to have it actually perform the operation on your files.
note
perl-rename is not to be confused with rename from util-linux, so make sure you have the right one installed.