--- a/include/common.h
+++ b/include/common.h
@@ -137,10 +137,12 @@ static inline bool prompt(const char *ms
 		}
 
 		if (strcmp("\n", line) != 0) {
-			switch (rpmatch(line)) {
-			case 0: ret = false; break;
-			case 1: ret = true; break;
-			case -1:
+			switch (line[0]) {
+			case 'N':
+			case 'n': ret = false; break;
+			case 'Y':
+			case 'y': ret = true; break;
+			default:
 				puts("unknown response; please try again");
 				continue;
 			}