creating service from executing a JAR file in UBUNTU - service

Question

I'm trying to create a service from executing a jar file in Ubuntu machine. I have created a wrapper with the below code
#!/bin/sh
SERVICE_NAME=MyService
PATH_TO_JAR=/home/nani/Documents/My_Build_executable/My_Build-12-06.jar
PID_PATH_NAME=/tmp/MyService-pid
case $1 in
start)
echo "Starting $SERVICE_NAME ..."
if [ ! -f $PID_PATH_NAME ]; then
nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &
echo $! > $PID_PATH_NAME
echo "$SERVICE_NAME started ..."
else
echo "$SERVICE_NAME is already running ..."
fi
;;
stop)
if [ -f $PID_PATH_NAME ]; then
PID=$(cat $PID_PATH_NAME);
echo "$SERVICE_NAME stoping ..."
kill $PID;
echo "$SERVICE_NAME stopped ..."
rm $PID_PATH_NAME
else
echo "$SERVICE_NAME is not running ..."
fi
;;
restart)
if [ -f $PID_PATH_NAME ]; then
PID=$(cat $PID_PATH_NAME);
echo "$SERVICE_NAME stopping ...";
kill $PID;
echo "$SERVICE_NAME stopped ...";
rm $PID_PATH_NAME
echo "$SERVICE_NAME starting ..."
nohup java -jar $PATH_TO_JAR /tmp 2>> /dev/null >> /dev/null &
echo $! > $PID_PATH_NAME
echo "$SERVICE_NAME started ..."
else
echo "$SERVICE_NAME is not running ..."
fi
;;
esac
but I'm ge stuck with the PID_PATH_NAME. what is this PID and what exactly I need to do to configure/create/modify this one? please help me.

Answer 1

The term PID stands for Process IDentifier, and is a unique number each process gets. By saving the PID to a file, the system can later find the PID of the service, and will be able to, for example, send a stop-signal to the service when it should be stopped.