Modifying/automating the spring_boot script, dc-jmx-1.1.9?

Question

Command line

Hello everyone,
help a novice Unix driver to deal with the modification of scriptab where the tasks are stacked like this:

# 1. function procces_State
# Initial - check: not starting, not ready for processing
# Running - running
# Stopped - standing still
# Suspend - processing completed
# Write the status to a variable for further processing
# 2. function start_DC_Procces
# Start processing if the application is in status "Initial" or "Stopped"
# 3. function stop_DC_Procces
# Stop processing if application is in "Running" status

The problem is that I have never encountered a shell, in Unix I can cd and ls -l.
Can someone please take a look and show how to assemble these functions correctly ...
Thank you very much in advance.
In conclusion, I will throw off the original script

#!/bin/bash

# File containing the pid (beaware that this file name defaults to application.pid by spring convention.
# If the variable is changed here you need to add the property "spring.pidfile" too
PIDFile="application.pid"

# JAR to be started
JAR=`ls ./jar/`

# Load the environment properties
source ./config/environment.properties




# check the JAVA_HOME path
if [ ! -e $JAVA_HOME/bin/java ]
 then
    echo "[ERROR] Invalid path. No java executable found at JAVA_HOME=$JAVA_HOME"
    exit 1
 else
    echo "[OK] Found java binary..."
fi




# check if the application.pid file exists
check_if_pid_file_exists(){
 if [ ! -f $PIDFile ]
  then
  	echo "Process not running"
   exit 1
 fi
}



# check if the process mentioned in the pid file is still running
check_if_process_is_running(){
 if ps -p "$(print_process)" > /dev/null
 then
     return 0
 else
     return 1
 fi
}



# check the status
status(){
    check_if_pid_file_exists
    if check_if_process_is_running
    then
      echo "$(print_process) is running"
    else
      echo "PIDFile=$PIDFile does not exist"
    fi
}




# stop the application
stop() {

# first of all check if the process is still running
    if [ ! -f $PIDFile ] || ! check_if_process_is_running
    then
      echo "Process "$(print_process)" not running"
    rm -f $PIDFile
      exit 0
    fi

# Term the process if it's still running
    kill -TERM "$(print_process)"
    echo -ne "Waiting for process to stop"
    NOT_KILLED=1
    for i in {1..20}; do
   if [ -f $PIDFile ] && check_if_process_is_running
      then
        echo -ne "."
        sleep 1
      else
        NOT_KILLED=0
      fi
    done
    echo

# Maybe the process was not terminated. Info and exit. Someone needs to check that.
    if [ $NOT_KILLED = 1 ]
    then
      echo "Cannot kill process "$(print_process)" "
      exit 1
    fi

    echo "Process stopped"
  rm -f $PIDFile
}


# start the application
start() {
    if [ -f $PIDFile ] && check_if_process_is_running
    then
      echo "Process "$(print_process)" already running"
      exit 1
    fi


    echo "nohup $JAVA_HOME/bin/java $JAVA_OPTS $2 -jar ./jar/*.jar > ./log/nohup.log 2>&1 &"
    nohup $JAVA_HOME/bin/java $JAVA_OPTS $2 -jar ./jar/*.jar > ./log/nohup.log 2>&1 &

    sleep 5
    echo -e "\nProcess started:" `cat $PIDFile`
}


# start the application
docker_start() {
    if [ -f $PIDFile ] && check_if_process_is_running
    then
      echo "Process "$(print_process)" already running"
      exit 1
    fi


    echo "nohup $JAVA_HOME/bin/java $JAVA_OPTS $2 -jar ./jar/*.jar > ./log/nohup.log 2>&1"
    nohup $JAVA_HOME/bin/java $JAVA_OPTS $2 -jar ./jar/*.jar > ./log/nohup.log 2>&1

    sleep 5
    echo -e "\nProcess started:" `cat $PIDFile`
}


# print the pid
print_process(){
    echo "$(cat $PIDFile)"
}


# evaluate options: start, stop, status ...
evaluate_option() {
    case "$1" in
          status)
                status
            ;;
          stop)
                stop
                exit 0
            ;;
          start)
                start
                exit 0
            ;;
          pid)
                print_process
            ;;
          dump)
                exec "./tools/heapdump.sh"
            ;;
          memmap)
                exec "./tools/memmap.sh"
            ;;
          tdump)
                exec "./tools/threaddump.sh"
            ;;
          Quit)
                exit 0
            ;;
          Docker)
                docker_start
                exit 0;
            ;;
          *)
            clear
            echo "Invalid action. Please select between start|stop|status|pid|dump|memmap|tdump"
    esac
}


# Evaluate the command line argument (script works with and without command line arguments)
if ! [ -z $1 ]
 then
# evaluate command line option
     evaluate_option $1
 else

# show menu
     OPTIONS="status stop start pid dump memmap tdump Quit Docker"
     select opt in $OPTIONS
     do
        evaluate_option $opt
     done
fi