Use gunzip instead of zcat; zcat expects input files to have a .Z suffix on a Mac with no option switch to ignore the requirement.
Use gunzip instead of zcat; zcat expects input files to have a .Z suffix on a Mac with no option switch to ignore the requirement.

pegasus-isi/pegasus-gtfar,pegasus-isi/pegasus-gtfar,pegasus-isi/pegasus-gtfar,pegasus-isi/pegasus-gtfar