#!/usr/bin/perl -i.bak
# in-place editing; save the original file with a .bak extension

use Win32::Console;
use strict;


open(STDERR, ">error.log") or die "Can't open error log: $!\n";

my $con = Win32::Console->new();

$con->Mode(ENABLE_WINDOW_INPUT | ENABLE_PROCESSED_INPUT |
           ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT |
           ENABLE_PROCESSED_OUTPUT | ENABLE_WRAP_AT_EOL_OUTPUT);

$con->Display;

$con->Write("Please enter the agent ID number: ");

chomp(my $port = <STDIN>);

$con->Write("The port number to use is $port.\n"); #Debug stuff, this works

{
  local @ARGV = "c:\\blah.txt";
  # set up a temporary @ARGV for in-place editing

  while (<>) {
    s/serverport 111$/serverport $port/;
    print;
  }
}