Too dangerous: m3cc/src/m3makefile if stale(build_dir & "/clean_marker.txt", "../src/clean_marker.txt") or defined ("FORCE") m3cc_Run(["rm -rf " & build_dir & "/*"]) cp_if("../src/clean_marker.txt", build_dir & "/clean_marker.txt") end ? If build_dir has a space..? - Jay