> my $seqin = Bio::SeqIO->new(-format => $informat, $file ? -fh > => \*ARGV); In that way, you have the same magic as the > diamond/pulp fiction operator <> > Of course, this should be (some copy/paste remnants): my $seqin = Bio::SeqIO->new(-format => $informat, -fh => \*ARGV); ML