diff --git a/libbb/compare_string_array.c b/libbb/compare_string_array.c
index 151b50817..ec7f94e79 100644
--- a/libbb/compare_string_array.c
+++ b/libbb/compare_string_array.c
@@ -23,7 +23,7 @@ int index_in_strings(const char *strings, const char *key)
 {
 	int idx = 0;
 
-	while (strings[0]) {
+	while (*strings) {
 		if (strcmp(strings, key) == 0) {
 			return idx;
 		}
@@ -57,7 +57,7 @@ int index_in_substrings(const char *strings, const char *key)
 
 	if (len) {
 		int idx = 0;
-		while (strings[0]) {
+		while (*strings) {
 			if (strncmp(strings, key, len) == 0) {
 				return idx;
 			}
diff --git a/networking/libiproute/ip_parse_common_args.c b/networking/libiproute/ip_parse_common_args.c
index 294bde540..5e4012b81 100644
--- a/networking/libiproute/ip_parse_common_args.c
+++ b/networking/libiproute/ip_parse_common_args.c
@@ -54,7 +54,7 @@ char **ip_parse_common_args(char **argv)
 				break;
 			}
 		}
-		arg = index_in_strings(ip_common_commands, opt);
+		arg = index_in_substrings(ip_common_commands, opt);
 		if (arg < 0)
 			bb_show_usage();
 		if (arg == ARG_oneline) {