#! C:\Perl\bin\perl.exe
use strict;

my $file = "controls.txt";
open (FH, "< $file") or die "Can't open $file for read: $!";

my @lines;
while (<FH>) {
    push (@lines, $_);
}

my %seen = ();
my @uniq = ();
foreach @lines {
        unless ($seen{$item}) {
                #if we get here, we have not seen it before
                $seen{$item} = 1;
                push(@uniq, $item);
        }
}

close FH or die "Cannot close $file: $!";
print @lines;    # see if it worked