#!/usr/bin/perl
use warnings;
use v5.14;

{
  no warnings 'uninitialized';
  if ('ssd' ne undef) {
    say "The strings are not equal";
  }
}

{
  no warnings 'uninitialized';
  if ('' eq undef) {
    say "The strings seem equal";
  }
}

##</code><code>##

The strings are not equal
The strings seem equal