#!/usr/bin/perl
use strict;
use warnings;
use 5.016;

chomp (my @data_lines = <DATA>);

# Sort the data lines according to the "Company Name" field and then the "Invoice ID" field.
@data_lines = sort {
    my ($company_name_a, $invoice_ID_a) = (split /\t/, $a)[1, 0];
    my ($company_name_b, $invoice_ID_b) = (split /\t/, $b)[1, 0];
    fc($company_name_a) cmp fc($company_name_b)
        or $invoice_ID_a <=> $invoice_ID_b
} @data_lines;

print "$_\n" for @data_lines;

__DATA__
1	SEBASTIAN COMMUNICATIONS
2	MASQUE SOUND
3	SEALEVEL SYSTEMS
4	MASSTECH, INC
5	SE INTERNATIONAL
6	SOUTHEAST SERVO, LLC
7	SEALEVEL SYSTEMS, INC.
8	MASTERBILT

##</code><code>##

2	MASQUE SOUND
4	MASSTECH, INC
8	MASTERBILT
5	SE INTERNATIONAL
3	SEALEVEL SYSTEMS
7	SEALEVEL SYSTEMS, INC.
1	SEBASTIAN COMMUNICATIONS
6	SOUTHEAST SERVO, LLC

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use 5.016;

# Open the file for input, discard all the header lines, but stop on and save the column names in an array.
# Read all the remaining lines in to an array and close the file.
my $column_line = "";
$column_line = <DATA> while defined $column_line && !($column_line =~ /Invoice ID/i);
chomp(my @columns = split /\t/, $column_line);
chomp(my @data_lines = <DATA>);

# Sort the data lines according to the "Company Name" field and then the "Invoice ID" field.
my ($company_name_index) = grep { $columns[$_] eq "Company Name" } (0..$#columns);
my ($invoice_ID_index) = grep { $columns[$_] eq "Invoice ID" } (0..$#columns);
@data_lines = sort
{
	my($company_name_a, $invoice_ID_a) = (split /\t/, $a)[$company_name_index, $invoice_ID_index];
	my($company_name_b, $invoice_ID_b) = (split /\t/, $b)[$company_name_index, $invoice_ID_index];
	fc($company_name_a) cmp fc($company_name_b) or
	$invoice_ID_a <=> $invoice_ID_b
} @data_lines;

# Open the file for output, print a new header and the column line to it, then print the now sorted data to it and close the file.
print "Replacement Header Text Here\n\n$column_line";
print "$_\n" foreach @data_lines;

__DATA__
Original Header Text	
	
Invoice ID	Company Name
1	SEBASTIAN COMMUNICATIONS
2	MASQUE SOUND
3	SEALEVEL SYSTEMS
4	MASSTECH, INC
5	SE INTERNATIONAL
6	SOUTHEAST SERVO, LLC
7	SEALEVEL SYSTEMS, INC.
8	MASTERBILT

##</code><code>##

Replacement Header Text Here

Invoice ID	Company Name
2	MASQUE SOUND
4	MASSTECH, INC
8	MASTERBILT
5	SE INTERNATIONAL
3	SEALEVEL SYSTEMS
7	SEALEVEL SYSTEMS, INC.
1	SEBASTIAN COMMUNICATIONS
6	SOUTHEAST SERVO, LLC