dbmopen %ORIG, "original", 0666 or die; dbmopen %NOVA, "new", 0666 or die; # -- race condition start for my $key (keys %ORIG) { $NOVA{$key} = $ORIG{$key}; } dbmclose %ORIG; dbmclose %NOVA; unlink "original" link "new", "original" # race condition end unlink "new";