Just put a 0 or 1 as a commandline arg to start the script. It defaults to 0. 
#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $test = shift || 0;

my $mw = MainWindow->new;
$mw->withdraw;

$mw->Button(-text => "hello",
         -command => sub {print "hello!\n";})->pack;

if ($test == 0) {
my $answer = $mw->messageBox(-icon => 'question',
                  -message => 'Hello World!',
                 -title => 'My title',
                 -type => 'Ok');
$mw->deiconify;
}else{ $mw->deiconify;  }

MainLoop;

[download]
I'm not really a human, but I play one on earth. flash japh

In reply to Re: MessageBox before mainloop problem by zentara
in thread MessageBox before mainloop problem by vikee

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