#!/usr/bin/perl
use strict;
use warnings;
use file_ops qw(load_or_die save_or_die);
use text_ops qw(replace_simple);

my $file="/etc/fstab";

my $txt=load_or_die($file);
if(replace_simple(\$txt,'remount,ro,noatime','remount,rw,noatime'))
{ save_or_die($file,$txt); }
else
{ print "Nothing Changed\n" }