MOSQUITTO_SIGNAL(1) Commands MOSQUITTO_SIGNAL(1)

mosquitto_signal - a utility for sending signal events to Mosquitto brokers running on the local computer.

mosquitto_signal {-a | -p pid} signal

mosquitto_signal --help

mosquitto_signal is a utility that can send named signals to one or all instances of a Mosquitto broker running on the local computer.

On POSIX like systems, it is a convenient replacement for the kill(1) command, with the added enhancement of being able to use named signals rather than generic system signals like SIGUSR1, and with the ability to signal multiple brokers at once.

On Windows, it is the only means of sending signals to a broker.

-a

Send the given signal to all processes matching the name mosquitto. As with all signal sending, only those processes you have permission to send the signal to will receive the signal.

-p pid

Send the signal to a specific process id. mosquitto_signal will always attempt to send the corresponding signal to the given process and will not check whether it appears to be a mosquitto process.

The following named signals are available for use.

config-reload

Trigger the broker to reload its configuration file, if in use.

On POSIX like systems this can also be triggered using the SIGHUP signal. Note that SIGHUP is used by other named signals.

log-rotate

If the broker is using log_dest file, then this will trigger the broker to close and reopen the log file.

On POSIX like systems this can also be triggered using the SIGHUP signal. Note that SIGHUP is used by other named signals.

shutdown

Trigger the broker to quit.

On POSIX like systems this can also be triggered using the SIGINT signal.

tree-print

Trigger the broker to print a representation of the subscription and retain trees to stdout. This is intended for debugging purposes only.

On POSIX like systems this can also be triggered using the SIGUSR2 signal. Note that SIGUSR2 is used by other named signals.

xtreport

Trigger the broker to write some internal state information to /tmp/xtmosquitto.kcg.<pid>.<iteration> on POSIX systems or xtmosquitto.kcg.<pid>.<iteration> on Windows systems. This is intended for debugging purposes only.

This signal is only used by the broker when appropriate support is compiled in, which is not the case by default.

On POSIX like systems this can also be triggered using the SIGRTMIN signal.

mosquitto bug information can be found at https://github.com/eclipse-mosquitto/mosquitto/issues

mosquitto(7), mosquitto(8)

Roger Light <roger@atchoo.org>

03/26/2026 Mosquitto Project