#!/usr/bin/perl -w
use strict;

my $ex_line = q(perl -ne "if (/(\d{6})_/g){ chomp;print qq($1,),(split/;/,$_)[-1],qq(\n)};" input.dat);
my $stuff = `$ex_line`;
 my %hash;
for (split /\n/, $stuff) {
  my @arr = split/,/,$_;
  push @{$hash{$arr[0]}} , $arr[1];
}

foreach (keys %hash) {
 print "$_\t" . join / /, @{$hash{$_}} , qq(\n);
}

1;