Linux Bash Script to install and uninstall a JAR

#!/bin/bash
 
psLine=$(ps aux | grep  '[j]ava -jar.*demo-.*.jar.*')
# -n not empty, z empty
if [ -n "$psLine" ] ; then
      currentPid=$(echo $psLine | awk '{print $2}')
      echo Current appli running detected with pid=$currentPid
      printf "First, we stop the current application : "
      kill $currentPid
      timeout 10 tail --pid=$currentPid -f /dev/null
      if [ "$?" -eq "0" ]; then #ne eq
         echo "DONE"
      else
	 kill -9 $currentPid 
	 echo "WARN"
	 echo "Gracefuly stop not working, the process was killed"
      fi
   # Do something knowing the pid exists, i.e. the process with $PID is running
fi
 
printf "Install of the new application : "
nohup java -jar ~/demo-app/demo-0.0.1-SNAPSHOT.jar > mylog.txt  2>&1 &
sleep 2
 
i=0
while [[ $i -lt 5 ]] && [[ $statusCode != *"200"* ]]
do
       statusCode=$(curl -I "localhost:5544/greeting" 2>/dev/null | head -n 1)       
       sleep 2
       ((i++))
done
 
if [[ $statusCode == *"200"* ]]; then
  echo "DONE"
else
  echo "ERROR"
  echo The test url has returned bad responses. The last one : $statusCode	
  echo Please check the application state. To rollback use the script fooScript...
fi