diff --git a/demo/lenet.c b/demo/lenet.c
index 9e11992..9ceacb4 100644
--- a/demo/lenet.c
+++ b/demo/lenet.c
@@ -57,6 +57,7 @@ void arg_parser(int argc, char* const argv[])
 	}
 	if (!strlen(image_path) || !strlen(parameters_path)) {
 		printf("error: incomplete argument\n");
+		printf("run 'lenet -h' for help.\n");
 		exit(EXIT_FAILURE);
 	}
 }
diff --git a/demo/lenet_pack.c b/demo/lenet_pack.c
index b2a87c6..35165f5 100644
--- a/demo/lenet_pack.c
+++ b/demo/lenet_pack.c
@@ -30,7 +30,7 @@ void arg_parser(int argc, char* const argv[])
 	while ((c = parg_getopt(&ps, argc, argv, "hp:o:v")) != -1) {
 		switch (c) {
 		case 'h':
-			printf("Usage: [-h] -p parameters-path -o pack-name\n");
+			printf("Usage: [-h] -p pathname -o filename\n");
 			printf("-h: Displays this message\n");
 			printf("-p: Choose parameters file path\n");
 			printf("-o: Output file name\n");
@@ -58,6 +58,7 @@ void arg_parser(int argc, char* const argv[])
 	}
 	if (!strlen(parameters_path) || !strlen(parameters_pack)) {
 		printf("error: incomplete argument\n");
+		printf("run 'lenet_pack -h' for help.\n");
 		exit(EXIT_FAILURE);
 	}
 }
diff --git a/demo/lenet_unpack.c b/demo/lenet_unpack.c
index ab36b88..cb5e49f 100644
--- a/demo/lenet_unpack.c
+++ b/demo/lenet_unpack.c
@@ -46,6 +46,7 @@ void arg_parser(int argc, char* const argv[])
 	}
 	if (!strlen(image_path) || !strlen(parameters_path)) {
 		printf("error: incomplete argument\n");
+		printf("run 'lenet_unpack -h' for help.\n");
 		exit(EXIT_FAILURE);
 	}
 }
diff --git a/makefile b/makefile
index 9e3aa17..d7a82c5 100644
--- a/makefile
+++ b/makefile
@@ -95,7 +95,7 @@ util_log.o util_vec.o util_image.o global_fn_cfg.o
 CATCOON_A = libcatcoon.a
 
 APPS_DEMO = simple lenet lenet_pack lenet_unpack 
-APPS_UTIL = packager listpkg
+APPS_UTIL = lspkg mkpkg
 
 APP_NAMES  = $(APPS_DEMO) $(APPS_UTIL)
 APP_INC   += $(INC)
diff --git a/util/listpkg.c b/util/lspkg.c
similarity index 77%
rename from util/listpkg.c
rename to util/lspkg.c
index 0f57149..099e6e6 100644
--- a/util/listpkg.c
+++ b/util/lspkg.c
@@ -8,8 +8,8 @@
 int main(int argc, char const *argv[])
 {
 	if (argc != 2) {
-		printf("Usage: listpkg package-file\n");
-		exit(-1);
+		printf("Usage: lspkg package-file\n");
+		exit(EXIT_FAILURE);
 	}
 	cc_tsrmgr_import(argv[1]);
 	cc_tsrmgr_list();
diff --git a/util/packager.c b/util/mkpkg.c
similarity index 98%
rename from util/packager.c
rename to util/mkpkg.c
index b0f5372..c6eb5d8 100644
--- a/util/packager.c
+++ b/util/mkpkg.c
@@ -33,7 +33,7 @@ void arg_parser(int argc, char* const argv[])
 	while ((c = parg_getopt(&ps, argc, argv, "hp:o:v")) != -1) {
 		switch (c) {
 		case 'h':
-			printf("Usage: [-h] -p parameters-path -o pack-name\n");
+			printf("Usage: [-h] -p pathname -o filename\n");
 			printf("-h: Displays this message\n");
 			printf("-p: Choose parameters file path\n");
 			printf("-o: Output file name\n");
@@ -61,6 +61,7 @@ void arg_parser(int argc, char* const argv[])
 	}
 	if (!strlen(parameters_path) || !strlen(parameters_pack)) {
 		printf("error: incomplete argument\n");
+		printf("run 'mkpkg -h' for help.\n");
 		exit(EXIT_FAILURE);
 	}
 }