#!/usr/bin/perl

use strict;
use warnings;
use File::Find;

my $base = '/var/www/noc/calendarsPostCalendars';
my $s1   = 'POSTCALENDARN';
my $s2   = 'POSTCALENDARS';
my $s3   = 'postcalendarn_';
my $s4   = 'postcalendars_';
my $s5   = 'PostCalendarn';
my $s6   = 'PostCalendars';


find(\&wanted, $base);

sub wanted {

    if ((-f $File::Find::name) && ($File::Find::name !~ m/\.bak/)) {
        my $file = $File::Find::name;
        my $file_old = $file . '.bak';

        rename($file, $file_old);
        open(IN, $file_old) or die($!);
        open(OUT, '>' . $file) or die($!);
        while (<IN>) {
            s/$s1/$s2/;
            s/$s3/$s4/;
            s/$s5/$s6/;

            print OUT $_;
        }
        close(OUT);
        close(IN);
    }
}