open INPUT, "$ENV{HOME}/flat_file"
   or die $!;

my %ports;
while (my $line = <INPUT>) {
    chomp $line;
    my ($code, $city) = split /\|/, $line; 
    $ports{$code} = $city
       if not $ports{$code};
}

for my $key (keys %ports) {
    if ($ARGV[1] =~ /$key/) {
        print $ports{$key}, "\n";
    }
}

close INPUT;

##</code><code>##

use Storable qw(retrieve);

my $ports = retrieve("$ENV{HOME}/flat_file.dat");

##</code><code>##

#!/usr/bin/perl

use strict;
use Getopt::Std;

my %parms;
getopts ("c:p:", \%parms);

die "Please supply a port code or city"
    if not $parms{p} and not $parms{c};

use Storable qw(retrieve);

if ($parms{p}) {
    $parms{p} = uc $parms{p};
    my $ports_by_code = retrieve("$ENV{HOME}/flat_file_by_port");
    print $ports_by_code->{$parms{p}}, "\n";
}
if ($parms{c}) {
    $parms{c} = uc $parms{c};
    my $ports_by_city = retrieve("$ENV{HOME}/flat_file_by_city");
    print $ports_by_city->{$parms{c}}, "\n";
}