OK, I've been asked to provide a bit more detail and provide a code sample. The external program is the command line interface to the Responsys Interact system

In my script, I have a call that goes like:

my $editcampaign = $cliObj->editcampaign(
campaign    => "Fake_Test_Campaign",
folder        => "Big_Fake_Directory_For_testing_only",
dist        => "Big_Fake_Directory_For_testing_only test_data_source",
html        => "Big_Fake_Directory_For_testing_only fake_file.htm",
aol        => "Big_Fake_Directory_For_testing_only fake_file.aol",
text        => "Big_Fake_Directory_For_testing_only fake_file.txt",
autosense    => 1,
);
[download]

Then with in the package I'm building, I'm generating the command string with:

sub editcampaign {
    my $self = shift;
    my( $data, $ret );
    ( @_ ) ? ( %$data ) = @_ : return;
    return if ( ( !$data->{'campaign'} ) or ( scalar( keys %$data ) < 
+1  ) ) ;

    push @$ret, qq|-locale $data->{'locale'}|    if ( $data->{'locale'
+} );
    push @$ret, qq|-folder $data->{'folder'}|    if ( $data->{'folder'
+} );
    push @$ret, qq|-ackurl $data->{'ackurl'}|    if ( $data->{'ackurl'
+} );
    push @$ret, qq|-followup $data->{'followup'}|    if ( $data->{'fol
+lowup'} );
    push @$ret, qq|-test $data->{'test'}|        if ( $data->{'test'} 
+);
    push @$ret, qq|-optout $data->{'optout'}|    if ( $data->{'optout'
+} );
    push @$ret, qq|-dist $data->{'dist'}|        if ( ( $data->{'dist'
+} ) and ( $data->{'dist'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-html $data->{'html'}|        if ( ( $data->{'html'
+} ) and ( $data->{'html'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-text $data->{'text'}|        if ( ( $data->{'text'
+} ) and ( $data->{'text'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-aol $data->{'aol'}|        if ( ( $data->{'aol'} )
+ and ( $data->{'aol'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-attach $data->{'attach'}|    if ( ( $data->{'attac
+h'} ) and ( $data->{'attach'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-sentlog $data->{'sentlog'}|    if ( ( $data->{'sen
+tlog'} ) and ( $data->{'sentlog'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-ackdoc $data->{'ackdoc'}|    if ( ( $data->{'ackdo
+c'} ) and ( $data->{'ackdoc'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-responsedb $data->{'responsedb'}|    if ( ( $data-
+>{'responsedb'} ) and ( $data->{'responsedb'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-failedlog $data->{'failedlog'}|    if ( ( $data->{
+'failedlog'} ) and ( $data->{'failedlog'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-clicktrack $data->{'clicktrack'}|    if ( ( $data-
+>{'clicktrack'} ) and ( $data->{'clicktrack'} =~ /(.*) (.*)/ ) );
    push @$ret, qq|-clickthru $data->{'clickthru'}|    if ( ( $data->{
+'clickthru'} ) and ( $data->{'clickthru'} =~ /(.*) (.*) (.*) (.*)/ ) 
+);
    push @$ret, qq|-skipdup ON|        if ( $data->{'locale'} );
    push @$ret, qq|-autosense ON|        if ( $data->{'autosense'} );
    push @$ret, qq|-opensense ON|        if ( $data->{'opensense'} );
    push @$ret, qq|-useaccountwide ON|    if ( $data->{'useaccountwide
+'} );
    push @$ret, qq|-conversiontrack ON|    if ( $data->{'conversiontra
+ck'} );
    push @$ret, qq|-htmltoaol ON|        if ( $data->{'htmltoaol'} );
    push @$ret, qq|-autosenseaol ON|    if ( ( $data->{'autosenseaol'}
+ ) and ( ( $data->{'autosense'} ) or ( $data->{'opensense'} ) ) ) ;
    push @$ret, $data->{'campaign'};
    $ret = join " ", @$ret;

    # Log action
    $self->{'LOGGER'}->log( level => 'notice', message => "campaign $r
+et\n" );

    #execute it
    ( $ret ) = $self->executeCommand( "campaign $ret" );

    return 1;
}
[download]

The executeCommand call is the code provided in http://www.perlmonks.com/index.pl?node_id=151886 with a few minor tweeks made for logging and returning the results set.

Interesting side note: when I try this from the command line, I get a return saying:
Warning!!! Turning skip multipart OFF since auto-sense is used.
and the command still executes, setting all of the things I care about.

Any thoughts?

P.S. I will also gladly accept any style hints/pointers involved with creating the command line string.