Process F1 & F2 into F3 text files

process.pl

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

my $F1 = 'F1.txt';
my $F2 = 'F2.txt';
my $F3 = 'F3.txt';

my %f2_map;

open(my $fh2, '<', $F2) or die "Can't read $F2: $!";
while (my $line = readline($fh2)) {
    my ($key, $val) = split /[:-]/, $line;
    $f2_map{"$key $val"}++;
}
close $fh2;
#use Data::Dumper::Compact qw(ddc);
#warn __PACKAGE__,' L',__LINE__,' ',ddc(\%f2_map);

open(my $fh3, '>', $F3) or die "Can't write $F3: $!";

open(my $fh1, '<', $F1) or die "Can't read $F1: $!";
while (my $line = readline($fh1)) {
    my ($key, $val) = split /\s+/, $line;
    #warn __PACKAGE__,' L',__LINE__,' ',,"$key, $val\n";
    next if exists $f2_map{"$key $val"};
    print $fh3 $line;
}
close $fh1;

close $fh3;