>perl -wle "print abc;"
Unquoted string "abc" may clash with future reserved word at -e line 1.
Name "main::abc" used only once: possible typo at -e line 1.
print() on unopened filehandle abc at -e line 1.

>perl -wle "print -abc;"
-abc

##</code><code>##

>perl -wle "print -90.0.0.1"
-Z^@^@^A

>perl -wle "print -91.0.0.1"
Argument "[\0\0^A" isn't numeric in negation (-) at -e line 1.
0

##</code><code>##

$uint32_ip = unpack 'N', 90.0.0.1;