#!/usr/bin/perl

use warnings;
use strict;

my $substring = 'GATC';

while (<DATA>) {
    my (undef, @parts) = split /(?=$substring)/, $_, -1;
    pop @parts;

    my $distance = 0;
    $distance += length for @parts;

    printf "Average distance: %4.2f\n", $distance / @parts;
}

__END__
GAGAGACCCCGATCGAGAGACCCGATCFGAGAVCTGATCCCC
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