Noun Synonyms in WordNet
Given that the format of wn_s.pl is
s(112947045,1,'usance',n,1,0).s(200001742,1,'breathe',v,1,25).A very raw way of doing that would be to execute the following in your terminal to only take the lines from that file that have the ',n,' string.
grep ",n," wn_s.pl > wn_s_nouns_only.plThe file wn_s_nouns_only.pl will only have the entries that are marked as nouns.