while( defined(my $head = ) && defined(my $seq = ) && defined(my $qhead = ) && defined(my $quality = ) ){ substr($head, 0, 1, '>'); $extension = "\\.fastq"; $files =~ s/(.*)$extension(.*)/$1/; $file_name =$files; open OUTFILE, '>>', $file_name.".fasta"; print OUTFILE $head, $seq; }