OPTION NOXWAIT;
The -noxwait option is used to allow a system command to runin SAS and when it finishes, the user is returned to SAS without having to press enter. It can be issued from the CONFIG.SAS file, from the command that invokes the SAS System and from an options statement from within an AUTOEXEC.SAS file or the Program Editor.

In 6.08 another options named noxsync also governs how quickly you are returned to your SAS System session. If you have submitted noxsync, you are returned to SAS immediately and the DOS command is executed asynchronously (meaning in the background as the SAS System session continues). This option is usually submitted with the noxwait option to speed the submitting and returning to the SAS System session.

Others you can check sas help.

You can get the definition with proc options, see example below,

proc options ;
run;

proc options group=errorhandling;
run;

proc options OPTION=NOXWAIT;
run;

proc options OPTION=SOURCE DEFINE  VALUE;
run;

thank you for your guys' help