sudo apt update
sudo apt install -y mosquitto mosquitto-clients
sudo systemctl enable mosquitto
sudo systemctl start mosquitto

# 终端 1：订阅
tmosquitto_sub -h localhost -t test/topic

# 终端 2：发布
mosquitto_pub -h localhost -t test/topic -m "Hello, MQTT"

# 首次创建（-c = create）
sudo mosquitto_passwd -c /etc/mosquitto/password_file mqttuser

# 追加用户（不加 -c）
sudo mosquitto_passwd /etc/mosquitto/password_file anotheruser

listener 1883 0.0.0.0
allow_anonymous false
password_file /etc/mosquitto/password_file

sudo chown root:mosquitto /etc/mosquitto/password_file
sudo chmod 640 /etc/mosquitto/password_file
ls -l /etc/mosquitto/password_file

mosquitto -c /etc/mosquitto/mosquitto.conf --test-config
sudo -u mosquitto mosquitto -c /etc/mosquitto/mosquitto.conf -v

sudo systemctl daemon-reload
sudo systemctl restart mosquitto
sudo systemctl status mosquitto

# 订阅（-d 显示 debug 过程）
mosquitto_sub -h localhost -t test/topic -u mqttuser -P 'passwd' -d

# 发布
mosquitto_pub -h localhost -t test/topic -m 'yyes' -u mqttuser -P 'passwd' -d