/usr/bin/mosquitto_signal

mosquitto_signal is a tool for sending control signals to mosquitto.
                 it is primarily useful on Windows.
                 on other systems the `kill` tool can be used.

Usage: mosquitto_signal {-a | -p <pid>} <signal>
       mosquitto_signal --help

 -a :  signal all processes that match the name 'mosquitto'.
 -p :  specify a process ID to signal

<signal> may be one of:
 config-reload - reload the configuration file, if in use.
 log-rotate    - if using `file` logging ask the broker to close and reopen the
                 log file.
 shutdown      - quit the broker.
 tree-print    - (debug) print out subscription and retain tree information to
                 stdout.
 xtreport      - (debug) write internal data to xtmosquitto.kcg.<pid>.<iter>

See https://mosquitto.org/ for more information.