pseudo code:
#!/usr/bin/perl -w

use strict;
use warn;

my $REF;
my @LINES;
my $DPT_DIR=/shares/test/PPdir/

print "ENTER REF NUMBER";
chomp($REF = <>);

grep "$REF" */*.dpt
open my $FH, '<', *.dpt file grep has found
chomp(@LINES, $FH);
close $FH


##</code><code>##

Linux grep:

#grep -l ABC123 */*.dpt
lloydf/test.dpt <-- I need to read this file.