diff --git a/~/C/libserialport/listen.c b/~/C/libserialport/listen.c
index 69b9135..34090f5 100644
--- a/~/C/libserialport/listen.c
+++ b/~/C/libserialport/listen.c
@@ -1,19 +1,29 @@
 #include <libserialport.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
+#include <stdbool.h>
 
 /* Helper function for error handling. */
 int check(enum sp_return result);
 
-int main() {
-  int result;
+int main(int argc, char **argv) {
+  struct sp_port *serial_port;
+  char *port_name = "/dev/ttyACM0";
+
   const int size = 256;
   char *buffer = malloc(size + 1);
-  const char *port_name = "/dev/ttyACM0";
-  const unsigned int timeout = 1000;
-  struct sp_port *serial_port;
 
+  const unsigned int timeout = 1000;
+  int result;
+
+  if (argc != 2) {
+    printf("Usage: %s <port>\n", argv[0]);
+    return -1;
+  } else {
+    port_name = argv[1];
+  }
+
+  printf("Connecting to '%s'...\n", port_name);
   check(sp_get_port_by_name(port_name, &serial_port));
   check(sp_open(serial_port, SP_MODE_READ_WRITE));
 
@@ -22,8 +32,10 @@ int main() {
   check(sp_set_parity(serial_port, SP_PARITY_NONE));
   check(sp_set_stopbits(serial_port, 1));
   check(sp_set_flowcontrol(serial_port, SP_FLOWCONTROL_NONE));
+  puts("Connected.\n");
 
-  while (1) {
+
+  while (true) {
     int pos = 0;
 
     while (pos < size) {
@@ -43,7 +55,7 @@ int main() {
           pos++;
       }
 
-      printf("%s\n", buffer);
+      puts(buffer);
     }
   }