* client readline improve

src/client.c

@@ -128,11 +128,16 @@ int main(int argc, char *argv[]) {
 
   while (1) {
     fputs("f2b >> ", stdout);
-    fgets(line, sizeof(line) - 1, stdin);
+    if (!fgets(line, sizeof(line) - 1, stdin)) {
       if (feof(stdin)) {
         fputc('\n', stdout);
+      } else {
+        fputs("read error\n", stdout);
+      }
       break;
     }
+    if (line[0] == '\n')
+      continue;
     handle_cmd(line);
   }