use OBO::Parser::OBOParser; my $my_parser = OBO::Parser::OBOParser->new(); my $ontology = $my_parser->work("my_obo_ontology.obo"); foreach my $term (@{$ontology->get_terms()}) { print $term->id(), "\t", $term->def()->text(), "\n" if (defined $term->id() && $term->def()->text() && $term->is_obsolete()); }