diff --git a/src/grep.c b/src/grep.c
index 07329cf..b5444b8 100644
--- a/src/grep.c
+++ b/src/grep.c
@@ -54,6 +54,7 @@ static int addpattern(const char *str, const size_t size) {
 		}
 	}
 
+	char reg_error_flag = 0;
 	struct pattern **bckp = realloc(ptrns, sizeof(struct pattern *) * (ptrns_size + 1));
 	if (bckp == NULL)
 		goto ADDP_ERROR;
@@ -89,25 +90,25 @@ static int addpattern(const char *str, const size_t size) {
 		else if (w_flag)
 			snprintf(reg_str, rs_size + 4, "%s\\<%s%.*s%s\\>%s", (bol) ? "^" : "", (E_flag) ? "(" : "\\(", (int)size - bol - eol, ptrns[ptrns_size]->str + bol, (E_flag) ? ")" : "\\)", (eol) ? "$" : "");
 
-		char flag = 0;
-		if (regcomp(&ptrns[ptrns_size]->reg, reg_str, reg_flag) < 0)
-			flag = 1;
+		if (regcomp(&ptrns[ptrns_size]->reg, reg_str, reg_flag) != 0)
+			reg_error_flag = 1;
 
 		ptrns[ptrns_size]->reg_set = 1;
 		if (x_flag || w_flag)
 			free(reg_str);
 
-		if (flag)
-			goto ADDP_ERROR;
 	}
 
+	if (reg_error_flag)
+		goto ADDP_ERROR;
+
 	ptrns_size++;
 	return 0;
 
 ADDP_ERROR:
 	ptrns_size++;
 	free_patterns();
-	fprintf(stderr, "grep: %s\n", strerror(errno));
+	fprintf(stderr, "grep: %s\n", (reg_error_flag) ? "bad regex" : strerror(errno));
 	return 1;
 }
 
@@ -141,12 +142,21 @@ static int addpattern_file(const char *file) {
 	return ret;
 }
 
+static char *my_strcasestr(const char *s1, const char *s2) {
+	size_t len = strlen(s2);
+	for (; *s1; s1++)
+		if (!strncasecmp(s1, s2, len))
+			return (char *)s1;
+
+	return NULL;
+}
+
 static int cmp(const char *str1, const char *str2) {
 	if (x_flag)
 		return !((i_flag) ? strcasecmp : strcmp)(str1, str2);
 
 	else
-		return ((i_flag) ? strcasestr : strstr)(str1, str2) != NULL;
+		return ((i_flag) ? my_strcasestr : strstr)(str1, str2) != NULL;
 }
 
 static int grep(FILE *fp, const char *file) {