diff --git a/MQTT.py b/MQTT.py
index d25cff5..b645e89 100644
--- a/MQTT.py
+++ b/MQTT.py
@@ -13,9 +13,6 @@ def on_connect(client, userdata, flags, rc):
 
 
 def valid(msg, client):
-    p = subprocess.Popen(['cat /home/pi/device_name'], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
-    out, err = p.communicate()
-    device_name = out.decode('utf-8')
     origin_data = json.loads(msg.payload.decode('utf-8'))
     if 'msg' not in origin_data:
         client.publish('error', payload='msg must be supplied', qos=0)
@@ -23,7 +20,7 @@ def valid(msg, client):
     if 'device_name' not in origin_data:
         client.publish('error', payload='device_name must be supplied', qos=0)
         return False
-    if device_name.casefold() != origin_data['device_name'].casefold():
+    if device_name != origin_data['device_name']:
         return False
     return True
 
@@ -75,10 +72,12 @@ def exec_shutdown():
 import os
 
 if __name__ == '__main__':
-
+    p = subprocess.Popen(['cat /home/pi/device_name'], shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    out, err = p.communicate()
+    device_name = out.decode('utf-8').strip()
     while True:
         try:
-            client = mqtt.Client(client_id='s')
+            client = mqtt.Client(client_id=device_name)
             client.username_pw_set("demo", "123456")
             # Specify callback function
             client.on_connect = on_connect
diff --git a/__pycache__/tool.cpython-310.pyc b/__pycache__/tool.cpython-310.pyc
new file mode 100644
index 0000000..721a189
Binary files /dev/null and b/__pycache__/tool.cpython-310.pyc differ