#!/usr/bin/perl

use strict;

my $colfile="column.lst";
my $datfile="column.dat";
my $outfile="column.out";
my %seen;
my @a_column;
my @a_allcol;
my @a_colhdr;
my $datcol;
my $delcol;
my $outline;
my $line;
my $date_stamp;
my $i;

$date_stamp = localtime time;
print "START:  $date_stamp\n";

open COLFILE, "<$colfile"
  or die "can't open file: $!";

while ($delcol = <COLFILE>)
{
   chomp($delcol);
   $seen{$delcol}++;
}

close COLFILE
  or die "can't close file: $!";

open DATFILE, "<$datfile"
  or die "can't open file: $!";

$datcol = <DATFILE>;
chomp ($datcol);

@a_allcol = (split ' ', $datcol);

$i=0;

while ( $a_allcol[$i] )
{
   chomp ($a_allcol[$i]);

   unless ( $seen{$a_allcol[$i]} )
   {
      push (@a_column, $i);
      push (@a_colhdr, "$a_allcol[$i]");
      $seen{$a_allcol[$i]}++;
   }
   $i++;
}

undef @a_allcol;

open OUTFILE, ">$outfile"
  or die "can't open file: $!";

$outline = join(" ", @a_colhdr);
print OUTFILE "$outline\n";

undef @a_colhdr;

while($line = <DATFILE>)
{
   chomp($line);
   $outline = join(" ", (split ' ', $line) [@a_column]);
   print OUTFILE "$outline\n";
}

close DATFILE
  or die "can't close file: $!";

close OUTFILE
  or die "can't close file: $!";

$date_stamp = localtime time;
print "END:  $date_stamp\n";