alakaboo is right. In your code,

$temp =~ eval $out
[download]

is just checking to see if $_ matches the "regex" in $out, which yields a null string if it doesn't, to which you then apply the binding operator with $temp, which simply succeeds -- dunno why, but it does. Thus your test is true every time or false every time depending on how $_ matches up with the $out regex. If it matches, it is false (binding to an integer 1 fails); if it doesn't match, it is true (binding to a null string succeeds).