[Linux] Startup script fixed

#!/bin/bash
SCREEN_NAME=""


txtgrn=$(tput setaf 2) # Green
txtred=$(tput setaf 1) # Red
txtbld=$(tput bold) # Bold
txtreset=$(tput sgr0) # reset colors


if [ ! -x `which screen` ]; then echo "You have to install screen first!"; exit 1; fi
if [ ! -x `which java` ]; then echo "You have to install java first!"; exit 1; fi


cd $(pwd)


function checkTitle(){
    if [ -n "$1" ]; then
        SCREEN_NAME=$1
    else
        SCREEN_NAME=`grep -i 'server_screen_title' server.properties | tr -d '\n\r' | cut -f2 -d'='`
    fi


    if [ -z "$SCREEN_NAME" ]; then
        echo "${txtred}No server_title set. Set title to 'Rising World Server'${txtreset}"
        SCREEN_NAME="Rising World Server"
    fi


    if ! [[ $SCREEN_NAME =~ ^[a-zA-Z0-9_.-]+$ ]]; then
        echo "${txtred}The Server title contains invalid symbol. Only a-z A-Z 0-9 - _ . are allowed${txtreset}"
        exit 1;
    fi


}


case "$1" in
    start)
        checkTitle $2
        MEMORY=$(grep -i 'server_memory' server.properties | tr -d '\n\r' | cut -f2 -d'=')
        if [ -z "$MEMORY" ]; then
            echo "${txtred}No server_memory set. Server starts with 1024mb memory${txtreset}"
            MEMORY=1024
        fi
        if ! [[ $MEMORY =~ ^[0-9]+$ ]]; then
            echo "${txtred}The property 'server_memory' is not numeric${txtreset}"
            exit 1;
        fi


        if screen -ls | grep [.]${SCREEN_NAME}[[:space:]] > /dev/null
        then
            echo "${SCREEN_NAME} is already running";
        else
            screen -dmSL ${SCREEN_NAME} java -Xmx${MEMORY}m -Xms$(($MEMORY/2))m -jar server.jar


            if screen -ls | grep [.]${SCREEN_NAME}[[:space:]] > /dev/null
            then
                echo "${txtgrn}${SCREEN_NAME} is successfully started${txtreset}"
            else
                echo "${SCREEN_NAME} an error has orcuded${txtreset}"
            fi
        fi
    ;;
    stop)
        checkTitle $2
        if screen -ls | grep [.]${SCREEN_NAME}[[:space:]] > /dev/null
        then
            screen -S ${SCREEN_NAME} -p 0 -X quit
            echo "${txtgrn}${SCREEN_NAME} is successfully stopped${txtreset}"
        else
            echo "${txtred}No screen with name '${SCREEN_NAME}' found${txtreset}"
        fi


    ;;
    restart)
        $0 stop && $0 start || exit 1
    ;;
    status)
        checkTitle $2
        if screen -ls | grep [.]${SCREEN_NAME}[[:space:]] > /dev/null
        then
            echo "${SCREEN_NAME} is ${txtgrn}${txtbld}running${txtreset}"
        else
            echo "${SCREEN_NAME} is ${txtred}${txtbld}not running${txtreset}"
        fi
    ;;
    attach)
        checkTitle $2
        if screen -ls | grep [.]${SCREEN_NAME}[[:space:]] > /dev/null
        then
            screen -r ${SCREEN_NAME}
        else
            echo "${txtred}No screen with name '${SCREEN_NAME}' found${txtreset}"
        fi
    ;;
    *)
        echo "Usage: linux_startscript.sh {start|stop|restart|status|attach} [title]"
        exit 2
esac
exit 0