MOSQUITTO_SIGNAL(1)

📦
version 2.1.2 · 5 versions
, in alpine 3.24, fedora 44

💅 MOSQUITTO_SIGNAL 💅

okay bestie, so the manual page is literally called MOSQUITTO_SIGNAL(1) and it lives in the Commands section, and today we're gonna make it make sense. it's a whole tool for yeeting signal events at Mosquitto brokers on your local machine. no cap. 🫶

✨ NAME ✨

mosquitto_signal — a utility for sending signal events to Mosquitto brokers running on the local computer. that's it, that's the vibe. 🎀

🌸 SYNOPSIS 🌸

mosquitto_signal {-a | -p pid} signal

mosquitto_signal --help

like, you either go -a for everyone or -p pid for one specific guy, and then you name your signal. or you just cry for --help, which honestly? valid. 💅

🦋 DESCRIPTION 🦋

mosquitto_signal is a utility that can send named signals to one or all instances of a Mosquitto broker running on the local computer. main character energy: it can slide into a single broker's DMs or address the whole group chat. 👑

On POSIX like systems, it's a convenient replacement for the kill(1) command, bestie — with the added enhancement that you get to use named signals instead of generic system signals like SIGUSR1, plus the ability to signal multiple brokers at once. it's giving glow-up. ✨

On Windows, it is the only means of sending signals to a broker. literally the only one. no backup plan. 😭

💜 OPTIONS 💜

  • -a — send the given signal to all processes matching the name mosquitto. and bestie, listen: as with all signal sending, only those processes you actually have permission to send the signal to will receive the signal. permissions said no ❌, nothing happens. 🙈
  • -p pid — send the signal to a specific process id. heads up though: 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. so like… you can absolutely aim it at something random. it won't stop you. it's not your mom. 💀

⭐ SIGNALS ⭐

the following named signals are available for use. let's go through the roster 🧚

🌈 config-reload

trigger the broker to reload its configuration file, if in use. refresh, reload, rebrand 🎀

on POSIX like systems this can also be triggered using the SIGHUP signal. note that SIGHUP is used by other named signals too — she's a busy girl, okay? shared signal, shared responsibility. 💅

🍓 log-rotate

if the broker is using log_dest file, then this will trigger the broker to close and reopen the log file. out with the old log, in with the fresh new one. iconic behavior honestly. ✨

on POSIX like systems this can also be triggered using the SIGHUP signal. note that SIGHUP is used by other named signals too. yes, again. she gets around. 😭

🔥 shutdown

trigger the broker to quit. goodbye, farewell, exit stage left. 👋

on POSIX like systems this can also be triggered using the SIGINT signal. (that's the same vibe as smashing Ctrl+C, iykyk.)

🦄 tree-print

trigger the broker to print a representation of the subscription and retain trees to stdout. stress on intended for debugging purposes only — this is a behind-the-scenes peek, not a whole production feature, bestie. 🙈

on POSIX like systems this can also be triggered using the SIGUSR2 signal. note that SIGUSR2 is used by other named signals too. (sensing a pattern yet? 💀)

🎀 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. note the Windows one has no /tmp — she's built different. 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. so if nothing happens, it's not you, it's the build config. 😭

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

💀 BUGS 💀

mosquitto bug information can be found at https://github.com/eclipse-mosquitto/mosquitto/issues — go report it, they're lovely, and also it's how stuff gets fixed. 🫶

👀 SEE ALSO 👀

mosquitto(7), mosquitto(8) — go read those, they're the whole ecosystem, and you're gonna want the context. and not me saying "context" like a teacher, like actually useful context. 💜

🌸 AUTHOR 🌸

Roger Light <roger@atchoo.org> — the whole legend responsible for this. give him flowers. 💐

okay that's the whole page!! mwah 💋 — brought to you by the Mosquitto Project, version dated 02/09/2026. go signal some brokers responsibly, bestie. 🦋✨🎀

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