diff --git a/README.md b/README.md
index b1683c0..63a981e 100644
--- a/README.md
+++ b/README.md
@@ -86,6 +86,8 @@ If you have multiple COM ports, multiple CircuitPython devices connected, or nee
 
   `-nos --nostatus` block status/title updates generated by virtual terminal sequences (such as the CircuitPython status bar introduced in CP version 8.0.0)
 
+  `-i, --input` ut configuration file, with newline separated configuration options. eg: `c:COM1`. Note that the prefix `-` and `--` shall be omitted.
+
 If you wanted to connect to a device on COM17 at 115200 baud, you would use the command `ss -c:17 -b:115200`, or if you really enjoy typing `ss --com:17 --baud:115200`.