View all Active Parameters in a system

Checking All Active Parameters in a system.

1. You can view all active parameter in a system with T-code RZ10 or RZ11
2. Alternately, you may run report RSPARAM
3. RSPARAM report contains a list of all active parameter in the system
4. Execute T-code SA38 or SE38 and enter RSPARAM
5. Execute the report.( F8)

Select Execute and select the field Display also un-substituted (the system variable values are then displayed)

 
 It displays all the System Default Value and User-Defined Value for each parameter.

You can than double-click on any parameter and see what the current value is.

Source: 

http://help.sap.com/saphelp_nw04/helpdata/en/c4/3a62e3505211d189550000e829fbbd/content.htm