example.txt

$ mosquitto_sub -v -t 'processes/#'
processes/run.sh Starting
processes/run.sh Still running
processes/run.sh Still going strong at Tue Oct 22 15:49:07 CEST 2013
processes/run.sh That's it, folks!

mqttfuncs.sh

#(@)mqttfuncs.sh by Jan-Piet Mens <jpmens()gmail.com>
# Source into shell script, then:
#
#	mqtt "some debug output here"
#
# to show your program is still doing something.

progname=${progname:=$(basename $0)}
topic="processes/${progname}"
mqtt_opts="--quiet -h localhost -p 1883"

function mqtt() {
	# Ignore PUB errors
	mosquitto_pub ${mqtt_opts} -t "${topic}" -m "$*" || true
}

your-process.sh

#!/bin/sh

set -e 

source mqttfuncs.sh

mqtt Starting

# do something ..
mqtt "Still running"

# do more (or less) of the same ..

mqtt "Still going strong at `date`"

# ...

mqtt "That's it, folks!"