nonumber nodate ls = 84 在output中不显示页码，日期，定义行的大小为84，
MISSING=<'>character<'>  
Syntax Description
<'>character<'> specifies the value to be printed. The value can be any character. Single or double quotation marks are optional. The period is the default.Operating Environment Information:   The syntax that is shown above applies to the OPTIONS statement. However, when you specify the MISSING= system option on the command line or in a configuration file, the syntax is specific to your operating environment and may include additional or alternate punctuation. For details, see the SAS documentation for your operating environment.
关于formchar的可以参考：http://statweb.calpoly.edu/jdoi/web/classes/stat330/suppl_formchar.pdf