$! p1 is filename and mode to open file (filename/write or filename/append)
$! p2 is delimiter separating elements of list in p3
$! p3 is list of items to be written, one per line, into options file
$! p1 is filename and mode to open file (filename/write or filename/append)
$! p2 is delimiter separating elements of list in p3
$! p3 is list of items to be written, one per line, into options file