#!/usr/bin/perl

use strict;
use warnings;

my (@header,%data);
while (<DATA>) {
   if (/^n10/) { push @header, 'total'; }       # will it always be total?
   elsif (/^n01([^;]+);/) { push @header, $1; $data{$1} = "x"; }
   print;
}

$data{'total'} = "x";  # maybe compute a sum here instead :)

print join(' ', "g", @header), "\n";
print join(' ', "g", map { '-' x length($_) } @header), "\n";
print join(' ', "p", map { sprintf("%*s ", length($_)-1, $data{$_}) } @header), 
"\n";

__DATA__
line1
line2
n10total
n01chocoloate;more stuff
n01vanilla;more stuff