#! perl -slw
use strict;

my %cache;
my $u = sprintf("%0.8x",rand()*0xffffffff);

until( exists $cache{ $u } ) {
    $cache{ $u } = undef;
    $u = sprintf("%0.8x",rand()*0xffffffff);
}

printf "Produced %d unique keys before duplicating\n", scalar keys %cache;
printf "between %s and %s\n", (sort keys %cache)[ 0, -1 ];
__END__
P:\test>junk
Produced 454 unique keys before duplicating
between 00bdffff and ff89ffff

P:\test>junk
Produced 273 unique keys before duplicating
between 013dffff and feb5ffff

P:\test>junk
Produced 84 unique keys before duplicating
between 0183ffff and fe5bffff

P:\test>junk
Produced 94 unique keys before duplicating
between 001bffff and fbc1ffff