$var = 0;
$UserInputDir = "<mydir>";
opendir DH, $UserInputDir or die "Cannot open $UserInputDir: $!";
@files = readdir DH;
foreach $file (@files) {
   next if $file=~/^\./;
   $OldFileName = $file;
   $file =~ s/.*.Log/ObjMgr_enu_$var.Log/;
   $var = $var + 1;
   rename ($OldFileName,$file);
     }
	 closedir DH;