diff --git a/jni/pjproject-android/pjsip-apps/src/python/helper.mak b/jni/pjproject-android/pjsip-apps/src/python/helper.mak
index b4acce6..f9fdf34 100644
--- a/jni/pjproject-android/pjsip-apps/src/python/helper.mak
+++ b/jni/pjproject-android/pjsip-apps/src/python/helper.mak
@@ -2,16 +2,16 @@
 
 lib_dir:
 	@for token in `echo $(APP_LDFLAGS)`; do \
-		echo $$token | grep L | sed 's/-L//'; \
+		echo $$token | grep '\-L' | sed 's/-L//'; \
 	done
 
 inc_dir:
 	@for token in `echo $(APP_CFLAGS)`; do \
-		echo $$token | grep I | sed 's/-I//'; \
+		echo $$token | grep '\-I' | sed 's/-I//'; \
 	done
 
 libs:
 	@for token in `echo $(APP_LDLIBS)`; do \
-		echo $$token | grep \\-l | sed 's/-l//'; \
+		echo $$token | grep '\-l' | sed 's/-l//'; \
 	done