#! perl -slw
use strict;
use constant {
    CHROM => 'chromosome.txt',
    PROBES => 'probes.txt',
};

my $chrom;
open C, '<', CHROM or die CHROM . ": $!";
sysread C, $chrom, -s( CHROM ) or die $!;
close C;
$chrom = uc $chrom;

my %probes;
open P, '<', PROBES or die $!;
chomp, undef $probes{ $_ } while <P>;
close P;

warn time;
my $p;
for ( 0 .. length( $chrom ) - 10 ) {
    exists $probes{ $p = substr( $chrom, $_, 10 ) } and print "$p : $_";
}
warn time;