ok so I reread your post. I made some changes to the way I open the file handles. I'm still getting one error.

#!/usr/bin/perl 
use strict; 
use warnings; 
#use diagnostics; 

if (@ARGV = 2){ 
    my %delList;  
    open my $BEEPON, '>>', "./beepon.file" || die "Can't open beepon.f
+ile $!"; 
    open my $BEEPOFF, '>>', "./beepoff.file" || die "Can't open beepof
+f.file $!"; 
    open my $DELLIST, '<', $ARGV[0] || die "Can't open $ARGV[0] $!"; 
    
    foreach (<$DELLIST>){ 
        chomp($_);
        $delList{$_} = 1; 
    } 
    close $DELLIST; 
    open my $ORGLIST, '<' , $ARGV[1] || die "Cant open $ARGV[1] $!"; 
    
    foreach my $entry (<$ORGLIST>){ 
        chomp($entry);
        print { exists $delList{$entry} ? $BEEPON : $BEEPOFF } $entry 
+. "\n";
    }
close $BEEPON; 
close $BEEPOFF; 
}
[download]

here are the resulting errors:

$./delete_list_ver3.pl test.list test_master.1

readline() on closed filehandle $DELLIST at ./delete_list_ver3.pl line
+ 12.
Use of uninitialized value $ARGV[1] in concatenation (.) or string at 
+./delete_list_ver3.pl line 17.
Cant open  Bad file descriptor at ./delete_list_ver3.pl line 17.
[download]

WTF???

as far as the BeepOn Vs BeepOff are concerned... Not very descriptive taken out of context are they.

this is part of a bigger project that generates a config file for an asterisk conference bridge. I often find it necessary to move ID's from one list to the other, and this is the result.

honestly the boss is happy from the first iteration of this code; I'm not because I am interested in learning Perl, and learning how to use Perl effectively and efficiently, and this seems like a good learning project, (at least I've learned alot I think) and progressing my perl abilities will help me not only professionally but academically as well.

For the record I really appreciate your help all along the way.