$ PERL_HASH_SEED_DEBUG=1 perl -e1 HASH_SEED = 12018612040932336001 $ PERL_HASH_SEED_DEBUG=1 perl -e1 HASH_SEED = 4459772231957961225 ... #### #!/usr/bin/perl use Test::More; plan tests => 1; my %hash = ( "Zero","0","One","1","Two","2", "Three", "3", "Four", "4", "Five", "5", "Six", "6", ); print "$ENV{PERL_INVOCATION_COUNT}: "; # note: test string has been determined experimentally # (i.e. it might differ with your Perl) ok(join(' ', keys %hash) eq 'Five Four Three Zero Two Six One', q{same ordering}); if (++$ENV{PERL_INVOCATION_COUNT} < 100 ) { exec $0; }