my @k1=sort keys %h1; my @k2=sort keys %h2; my $k1; my $k2; while((scalar @k1 > 0)&&(scalar @k2 > 0)){ if(!defined $k1){ $k1=shift @k1; } if(!defined $k2){ $k2=shift @k2; } if($k1 eq $k2){ if($h1{$k1} ne $h2{$k2}){ # .. keys match but contents dont } undef $k1; undef $k2; }elsif($k1 lt $k2){ # .. key in k1 and not in k2 undef $k1; }else{ # .. key in k2 and not in k1 undef $k2; } } if(defined $k1){ foreach ($k1,@k1){ # .. key in k1 and not in k2 } } if(defined $k2){ foreach ($k2,@k2){ # .. key in k2 and not in k1 } }