Linux startup script for a Minecraft dedicated server

minecraft

#!/bin/bash
#
# ------------------------------------------------------
# Minecraft Startup Script for Unix
# ------------------------------------------------------
# minecraft      This shell script takes care of the Minecraft server instance 
#
# chkconfig: 2345 80 30
# description: minecraft is liquid awesome
# processname: java

DEFAULTS='/etc/default/minecraft'
PIDFILE='/var/run/minecraft/pid'
JARFILE='minecraft_server.jar'
ACTION="$1"

usage() {
    echo "Usage: $0 {start|stop|restart|status}"
    exit 1
}

[ $# -gt 0 ] || usage

if [[ ! -f "$DEFAULTS" ]]; then
  echo "Missing defaults file $DEFAULTS"                                                                                                                                           
  exit -1                                                                                                                                                                          
fi                                                                                                                                                                                 
                                                                                                                                                                                   
. "$DEFAULTS"                                                                                                                                                                      
                                                                                                                                                                                   
# JVM Memory Settings
[[ -n $JVM_MAX_MEMORY ]] && JAVA_OPTS="$JAVA_OPTS -Xmx$JVM_MAX_MEMORY -XX:+UseConcMarkSweepGC -XX:+UseAdaptiveGCBoundary -XX:+CMSClassUnloadingEnabled"

RUN_CMD="java $JAVA_OPTS -cp .:* -jar $JARFILE nogui $JAVA_ARGS"

export JAVA_HOME
export MINECRAFT_HOME
export PATH

case "$ACTION" in
  start)
        echo "Starting $APP_NAME: "
        cd $MINECRAFT_HOME
        su $RUN_AS_USER -c "$RUN_CMD" >> /dev/null 2>&1 &
        sleep 2
        MINECRAFT_PID=`ps -u minecraft -o pid,command | grep "$APP_NAME" | awk '{print $1}'`
        [[ -n $MINECRAFT_PID ]] && echo $MINECRAFT_PID > "$PIDFILE"
        ;;

  stop)
        if [[ -a "$PIDFILE" ]]; then
          MINECRAFT_PID=`cat $PIDFILE`
        elif [[ -n "$APP_NAME" ]]; then
          MINECRAFT_PID=`ps -u minecraft -o pid,command | grep "$APP_NAME" | awk '{print $1}'`
        else
          echo "Cannot find PID! Need either a PID file or an APP_NAME."
          exit -1
        fi

        ATTEMPTS=0

        echo -n "Shutting down $APP_NAME: $MINECRAFT_PID"
        kill $MINECRAFT_PID

        while [[ -n `ps -p $MINECRAFT_PID -o comm=` ]]; do
          echo -n "."
          sleep 1
          if [[ ++ATTEMPTS -gt 10 ]]; then
            echo -n "sending SIGKILL to $MINECRAFT_PID"
            kill -9 $MINECRAFT_PID
            break
          fi
        done

        echo
        ;;

  restart)
        $0 stop $*
        sleep 15
        $0 start $*
        ;;

  status)
        ROCKET_PS=`ps -ef | grep $APP_NAME`
        if [ -n "$ROCKET_PS" ]
        then
            echo "$APP_NAME running"
            exit 0
        else
            echo "$APP_NAME is currently not running."
        fi
        exit 1
        ;;

*)
        usage
        ;;
esac

exit 0