#!/usr/bin/perl
use warnings;
use strict;

my $infile = 'orders.txt';
my $output = 'orders_today.txt';

open my $IN, '<', $infile or die "ERROR: Cannot open '$infile': $!";

my @out;
while (<$IN>) {
    chomp;
    my @text = split /\t/;
    push @out, [@text];
}

open my $OUT, '>', $output or die "Cannot open '$output': $!";
print {$OUT} map "@$_\n", sort { $a->[10] cmp $b->[10] } @out;