You can use the SAS-maintained view DICTIONARY.COLUMNS and PROC SQL to count information about SAS dataset/library members. The SAS support
http://support.sas.com/ website has SAS-hosted documentation and supplemental technical papers and info resources on this type of topic, available by using the website search facility or a Google advanced search adding the site:sas.com parameter to limit the search to just that website/domain.
Scott Barry
SBBWorks, Inc.
Accessing SAS System Information by Using DICTIONARY Tables
http://support.sas.com/documentation/cdl/en/sqlproc/62086/HTML/default/a001385596.htm
Variable Names Don’t Begin with the Same Characters? No Problem: How to Create Variable List without Copying, Pasting or Excel Intervention Xu Zeng, Independent Consultant, Fairfax, VA
http://support.sas.com/resources/papers/proceedings09/053-2009.pdf