diff --git a/editors/awk.c b/editors/awk.c
index f7b8ef0d3..3594717b1 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -2348,17 +2348,19 @@ static char *awk_printf(node *n, size_t *len)
 		s = f;
 		while (*f && *f != '%')
 			f++;
-		c = *++f;
-		if (c == '%') { /* double % */
-			slen = f - s;
-			s = xstrndup(s, slen);
-			f++;
-			goto tail;
-		}
-		while (*f && !isalpha(*f)) {
-			if (*f == '*')
-				syntax_error("%*x formats are not supported");
-			f++;
+		if (*f) {
+			c = *++f;
+			if (c == '%') { /* double % */
+				slen = f - s;
+				s = xstrndup(s, slen);
+				f++;
+				goto tail;
+			}
+			while (*f && !isalpha(*f)) {
+				if (*f == '*')
+					syntax_error("%*x formats are not supported");
+				f++;
+			}
 		}
 		c = *f;
 		if (!c) {