#!/usr/bin/perl -w
use strict;
my @row;
my $separator=',';
open(INPUT,"< temp.txt") or die "could not open";
while(<INPUT>){ chomp; push @row,$_;};
foreach (@row) {
  s/(\\+)/$1$1/g;
}
print join($separator, @row);
print "\n";

##</code><code>##

aa
bb
\\c\c\
d\d