Error message : Global symbol %lines

I have the code below, which generates the error message:

#Global symbol "%lines" requires explicit package name at 002comparitor.pl line 20.

Could you explain how I can solve this error please ?

code:

#!usr/bin/perl

use strict;
use warnings;

my $fil = shift; # command line argument is the file to read lines from

open (INPUT,"<C:/Users/mickg/Desktop/Lessons/comp/master.txt") or die "can not open INPUT";
open (MATCH,"<C:/Users/mickg/Desktop/Lessons/comp/match.txt") or die "can not open MATCH";
open (NONMATCH,"<C:/Users/mickg/Desktop/Lessons/comp/nonmatch.txt") or die "can not open NONMATCH";


my @lines = map { chomp; $_ } <INPUT>;


while (@lines > 6) {
   
    # check first 5 lines against the 6th line
    my @match = grep { $_ eq $lines[5] } @lines[0..4];
    my @nomatch = grep {$_ ne $lines[5] } @lines{0..4};
   
    # do whatever you want with the matches and no-matches
   
    print MATCH @match;
   
    # get rid of first line so next loop will be 2-6 and so on
    shift @lines;
   
}

close (INPUT);
close (MATCH);
close (NONMATCH);