use strict; use warnings; use Tie::File::AnyData::Bio::Fasta; tie my @in,'Tie::File::AnyData::Bio::Fasta', shift @ARGV, or die $!; my $n = 0; for my $seq (@in){ tie my @out, 'Tie::File::AnyData::Bio::Fasta', "$n.fa" or die $!; $n++; @out = ($seq); untie @out; } untie @in;