INITSTMT= System Option works for this purpose too, but leaves 'em guessing when code reviewers try to figure out where those dang macro variables came from! :-)

sas -initstmt '%put you have used the initstmt; data x; x=1; run;'

http://support.sas.com/documentation/cdl/en/lesysoptsref/68023/HTML/default/viewer.htm#n16z79lqkz4a87n1urzo6mithnza.htm