#!/usr/bin/perl
use strict;
use warnings;

while (<DATA>)
        {
        chomp;

        # remove the pesky quotes at the beginning and end
        s/^"//;
        s/"$//;

        # change all doubled quotes into just singles
        s/""/"/g;

        print $_ . "\n";
        }
__DATA__
""
"a"""""
"a""b""c""d""f"
"This is a ""test"""
"Here we have """"a nested set of double-quoted quotes"" or whatever."""
"Harvey ""the Screwdriver"" Ledbetter"