perl true/false

perl treat 0 false, non 0 ture.

print "false\n" if 0;
print "false\n" if 0;

------------------------
ture

perl treat string empty is false.

my $temp = "";
print "This is $temp\n" if $temp; 
$temp = "HelloWorld";
print "This is $temp\n" if $temp;

--------------------------------------------
This is HelloWorld