diff --git a/isotpserver.c b/isotpserver.c
index 448cacd..91719f0 100644
--- a/isotpserver.c
+++ b/isotpserver.c
@@ -100,28 +100,29 @@ void childdied(int i)
 void print_usage(char *prg)
 {
 	fprintf(stderr, "\nUsage: %s -l <port> -s <can_id> -d <can_id> [options] <CAN interface>\n", prg);
-	fprintf(stderr, "Options: (* = mandatory)\n");
-	fprintf(stderr, "\n");
+	fprintf(stderr, "Options:\n");
 	fprintf(stderr, "ip addressing:\n");
-	fprintf(stderr, " *       -l <port>    (local port for the server)\n");
+	fprintf(stderr, "         -l <port>    * (local port for the server)\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "isotp addressing:\n");
-	fprintf(stderr, " *       -s <can_id>  (source can_id. Use 8 digits for extended IDs)\n");
-	fprintf(stderr, " *       -d <can_id>  (destination can_id. Use 8 digits for extended IDs)\n");
-	fprintf(stderr, "         -x <addr>[:<rxaddr>] (extended addressing / opt. separate rxaddr)\n");
-	fprintf(stderr, "         -L <mtu>:<tx_dl>:<tx_flags> (link layer options for CAN FD)\n");
+	fprintf(stderr, "         -s <can_id>  * (source can_id. Use 8 digits for extended IDs)\n");
+	fprintf(stderr, "         -d <can_id>  * (destination can_id. Use 8 digits for extended IDs)\n");
+	fprintf(stderr, "         -x <addr>[:<rxaddr>]  (extended addressing / opt. separate rxaddr)\n");
+	fprintf(stderr, "         -L <mtu>:<tx_dl>:<tx_flags>  (link layer options for CAN FD)\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "padding:\n");
-	fprintf(stderr, "         -p [tx]:[rx] (set and enable tx/rx padding bytes)\n");
-	fprintf(stderr, "         -P <mode>    (check rx padding for (l)ength (c)ontent (a)ll)\n");
+	fprintf(stderr, "         -p [tx]:[rx]  (set and enable tx/rx padding bytes)\n");
+	fprintf(stderr, "         -P <mode>     (check rx padding for (l)ength (c)ontent (a)ll)\n");
 	fprintf(stderr, "\n");
-	fprintf(stderr, "rx path: (config, which is sent to the sender / data source)\n");
-	fprintf(stderr, "         -b <bs>      (blocksize. 0 = off)\n");
-	fprintf(stderr, "         -m <val>     (STmin in ms/ns. See spec.)\n");
-	fprintf(stderr, "         -w <num>     (max. wait frame transmissions)\n");
+	fprintf(stderr, "rx path:\n (config, which is sent to the sender / data source)\n");
+	fprintf(stderr, "         -b <bs>       (blocksize. 0 = off)\n");
+	fprintf(stderr, "         -m <val>      (STmin in ms/ns. See spec.)\n");
+	fprintf(stderr, "         -w <num>      (max. wait frame transmissions)\n");
 	fprintf(stderr, "\n");
-	fprintf(stderr, "tx path: (config, which changes local tx settings)\n");
-	fprintf(stderr, "         -t <time ns> (transmit time in nanosecs)\n");
+	fprintf(stderr, "tx path:\n (config, which changes local tx settings)\n");
+	fprintf(stderr, "         -t <time ns>  (transmit time in nanosecs)\n");
+	fprintf(stderr, "\n");
+	fprintf(stderr, "(* = mandatory option)\n");
 	fprintf(stderr, "\n");
 	fprintf(stderr, "All values except for '-l' and '-t' are expected in hexadecimal values.\n");
 	fprintf(stderr, "\n");