The file I am reading from contain the following :

c:\\tmp\\05152003.Log
c:\\tmp\\d25573786-.Log

c:\\tmp\\drwtsn32.log
c:\\tmp\\nbenv10
c:\\tmp\\nbenv11
c:\\tmp\\nbenv12

Here  a snippet of my script which I ran in the c:\ drive :

use strict;
use File::Find;
use Sys::Hostname;

my $fileupdate;
my $old_hostname = "d25573786-";
my ($orig,$concat,$new_hostname,$answer);
my @lines = " ";
my $new_hostname = "";
## Create new hostname based on physical address ###
$new_hostname = shift;
if ($new_hostname eq "" )
{
    $new_hostname = "css12345";
   print "Current host name of machine is :$old_hostname \n";
   print "The new host name is going to be: $new_hostname\n";
}

 if ( $old_hostname ne $new_hostname )
   {
     &personalization;
   }
 else
  {
    print "System already personlized\n";
   }
  chmod( 0777, $orig );

#---------------------------------------------------------------------------------------------
sub personalization
{    
   
   open(FH,"<c:\\person.txt") || die "Can't open arp.txt: $!\n";
    while(my $line = <FH>)
     {  
       
         if( $line =~ /(.*)$old_hostname(.*)/i ) # any files that contain the substring of the old hostname
        {    
             print "file that match $line\n";
             $orig = $line;
             $concat = $line;
             $concat =~ s/(.*)$old_hostname(.*)/$1$new_hostname$2/gi;

             #CALL UPDATE SUBROUTINE
             
             rename($orig, $concat) || print "error can't rename $orig to $concat: $!";
             
              &modified_file($concat);
             
         }
        else
           {
             &modified_file($orig );
           }
    }
}
#---------------------------------------------------------------------------------------------
sub modified_file
{  
          $fileupdate = shift;
         
   
          open (IN,"<$fileupdate");
         @lines = <IN>;
         close IN;
       
          my $change_count = 0;
         @lines = map { $change_count++ if s/$old_hostname/$new_hostname/sgi; $_ } @lines;
         next unless $change_count;
         open (OUT,">$fileupdate") || "can't open $fileupdate for writing :$! ";
         print OUT @lines;
          close OUT;
     
}