$ perl -T -MScalar::Util=tainted -wle 'print tainted $0 ? "Taint mode on" : "Taint mode off"' 
Taint mode on
$ perl    -MScalar::Util=tainted -wle 'print tainted $0 ? "Taint mode on" : "Taint mode off"' 
Taint mode off
$