#!/usr/bin/perl
use 5.016;
use warnings;

# 1068826  

my $data = '>b_comp_seq1 ACGCGGGGGAATTT >b_comp_seq2 ACGGAATT >b_comp_seq3 GGGGGCTTTCACC >b_comp_seq4 TACCGGGAATT';

my @data1 = split /\s/, $data;

my $i=0;
my ($data1, $fh, $fn);

for $_(@data1) { 
    $_ =~ />(.*)/;
    $fn = $1;
    if ( $i%2 == 0 ) {
        open $fh, ">", $fn or warn "Can't open $fh for write, $!";
        ++$i;
        print $fh "$fn \t $data1[$i]";
        say "  DEBUG: \$fn, \$data1[$i]: $fn, $data1[$i]";
        close $fh;
    } else {
        ++$i;
        #ALSO -- 
        # consider how to revert to writing to the first file for comp_seq_5
        # if that's the way you wish to order the elements; otherwise, revise
        # the code above to put the first four sequences and their source 
        # id's into the first file written.
    }
}


=head output files contain...

b_comp_seq1 	 ACGCGGGGGAATTT
b_comp_seq2 	 ACGGAATT
b_comp_seq3 	 GGGGGCTTTCACC
b_comp_seq4 	 TACCGGGAATT

=cut