I could be wrong, but this smells like a good opportunity to learn about Getopt::Long. I tend to use it with the hashref method like this.

    use Getopt::Long;
    my $opts = {};

    #
    # maybe set some overridable defaults...
    #
    $opts->{target} = 'foo';
    $opts->{cust}   = 'SMC';

    GetOptions( $opts,
                    'target=s',
                    'cust=s',
                    'cotime=s',
    );
[download]

Now, if you type your_script.pl --target bar --cust FET --cotime baz then your $opts hashref will be populated accordingly. $opts->{target} will be 'bar', $opts->{cust} will be FET, $opts->{cotime} will be 'baz'. Setting defaults as I've demonstrated allows you to skip some of the command line args.