If you have a bunch of folders with multiple volumes archive in them, there is a simple way to extract the information using bash.
First, let's assume we have a structure like this (folders):
Some.TVSeries.S02E01.DVDRip.XviD Some.TVSeries.S02E02.DVDRip.XviD Some.TVSeries.S02E03.DVDRip.XviD
and each of them follow the pattern (files):
$ ls Some.TVSeries.S02E01.DVDRip.XviD sometv-201.r01 sometv-201.r02 sometv-201.r03 ... sometv-201.rar
The extract command is:
unrar e Some.TVSeries.S02E01.DVDRip.XviD/sometv-201.rar /folder/extracted/content
but you try to avoid doing so for each folder you have. So, the solution is (we assume that we have 12 identical pattern folders):
for r in $(seq 1 12); do a=`printf '%.02d' $r`; unrar e Some.TVSeries.S02E$a.DVDRip.XviD/sometv-2$a.rar /folder/extracted/content; done
Note: We're using here printf to get numbers as 01, 02 … 12 (with the leading 0).