A Bash library for daemonizing a script

You can clone this repository or download it as a zip file. To clone:

git clone https://github.com/david-moreno/bash-libdaemon.git
cd bash-libdaemon
sudo make install

Using the cloned/unzipped directory:

cd bash-libdaemon
sudo make uninstall

Returns the current PID file directory

The default is /var/run

Sets the current PID file directory

dir must be an absolute path

The script must have write permissions on dir

Returns the current PID file name

Sets the current PID file name

The default is [script_name].pid

Creates the PID file

Determines if an older PID file exists

Determines if the PID file has the same PID than the current script

Deletes the pid file

Daemonizes the script

The function main will be executed in an endless loop

The function terminate will be executed on SIGINT SIGHUP SIGTERM or SIGKILL

PID file deleting and the exit call are added automatically

This script (libdaemon-test.sh) creates the PID file foo.pid on the current working directory, checks if an existing PID file exists, runs the daemonized script and writes dots and some messages on the test.log file until a SIGINT,SIGHUP, SIGTERM or SIGKILL signal is received:

#!/bin/bash

source "/usr/lib/bash/libdaemon"

NAME="foo.pid"
DIR=`pwd`
LOG="$DIR/test.log"

#This function will be executed on SIGINT SIGHUP SIGTERM or SIGKILL
#The PID file deleting and the 'exit' call are added automatically.
function term {
	echo -e "\n* $0: Exiting">>$LOG
}

#This function will be executed on and endless loop.
function main {
	echo -n ".">>$LOG
	sleep 1
}

#Please note that the directory *must* be an absolute path.
dmn_set_pidf_name $NAME
dmn_set_pidf_dir $DIR

#Checks if a PID file already exists.
(( `dmn_pidf_exists` )) && {
	echo -e "\n* $0: pidfile exists, exiting">>$LOG
	exit
}
dmn_pidf_create

echo -e "\n* $0: Initiating">>$LOG

#Daemonizes the script.
dmn_start main term

You can check the daemon output with tailf test.log:

* ./libdaemon-test.sh: Initiating
............

If you issue a killall libdaemon-test.sh command, the script with terminate and test.log will show the message:

* ./libdaemon-test.sh: Exiting