This script may be the most important one. It basically compares two sets of transcripts and keeps those from the first set which overlap with the second one. The first set is considered as the query set (basically, your data) and the second one is the reference set (RefSeq data, for example).
It is vital to understand that it will output the elements of the first file which overlap with the elements of the second one.
Various modifiers are also available:
-Invert selection (report those which do not overlap).
-Restrict to collinear / anti-sense overlapping data.
-Keep the query data even if they do not strictly overlap with the reference data, but are located not further away than n nucleotide from some reference data.
Some option reverses the selection. Put in other words, it performs the comparison as usual, and outputs all those query data which do not overlap.