##  	my $commandstring = $self->executable."$instring"."$param_string";
##        $commandstring .= ' 1>/dev/null' if $quiet;
##        $self->debug( "clustal command = $commandstring");
##        
##        my $status = system($commandstring);
      	my @command = ( $self->executable, $instring, $param_string );
        $self->debug( "clustal command = @command ");
        
        my $status = system(@command);