use strict;
use warnings;
use Data::Dumper;

my @rows;               # Store the rows here
my @empty;              # If we see a true value we put it here
while (<>) {            # read a line at a time
  chomp;                # lose the newline
  my @row=split /;/;    # split the line by ;
  push @rows,\@row;     # store the row 
  $empty[$_]||=$row[$_] # Equivelent to saying $empty[$_] or ($empty[$_]=$row[$_])
     for 0..$#row;      #   for each column
}
print "Empty columns:",join(", ",grep { $empty[$_] } 0..$#empty),"\n";
print Data::Dumper->Dump([\@rows],['*rows']);