Minecraft server admin script.

server_admin.sh

#!/bin/bash

## Name of the script used to start the server.
# This will be written by this script in the directory you run it in.
# Avoid ServerStart.sh because this will collide with FTB Server scripts.
CONTROL_SCRIPT="ServerAdminStart.sh"

## Memory options
# -Xms controls initial memory.
# -Xmx controls maximum memory threshold.
# PermSize is something...
MEMORY_OPTS="-Xms512m -Xmx2000m -XX:PermSize=256m"

## Additional java options.
# Basic optimizations.
JAVA_OPTIONS="-d64 -server -XX:+UseConcMarkSweepGC -XX:+UseParNewGC"

# Some random optimized config from the internet.
#JAVA_OPTIONS="-d64 -server -XX:CompileThreshold=3000 -XX:+UseConcMarkSweepGC -XX:+UseParNewGC -XX:MaxHeapFreeRatio=20 -XX:MinHeapFreeRatio=12 -XX:NewSize=100m -XX:SurvivorRatio=6 -XX:MaxTenuringThreshold=4"

# FTB Server optimizations
JAVA_OPTIONS="-d64 -XX:+UseParNewGC -XX:+CMSIncrementalPacing -XX:+CMSClassUnloadingEnabled -XX:ParallelGCThreads=2 -XX:MinHeapFreeRatio=5 -XX:MaxHeapFreeRatio=10"

# I have no idea where this came from..
JAVA_LOG_OPTIONS=" -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintCommandLineFlags -XX:+PrintGCDetails -Xloggc:GC.log"

# If you want to play with JMX debuging you can uncomment these and poke around.
JMXPORT=9010
JMXPWFILE="$HOME/jmxremote.password"
JMXACCESSFILE="$HOME/jmxremote.access"
#JMX_OPTIONS="-Dcom.sun.management.jmxremote=true -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.authenticate=true -Dcom.sun.management.jmxremote.port=$JMXPORT -Dcom.sun.management.jmxremote.password.file=$JMXPWFILE -Dcom.sun.management.jmxremote.access.file=$JMXACCESSFILE"
#JMX_OPTIONS="-Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.ssl=false -Dcom.sun.management.jmxremote.port=$JMXPORT -Dcom.sun.management.jmxremote.authenticate=false -Djava.rmi.server.hostname=localmachine.example.com"
JMX_OPTIONS=""

## END CONFIG ##
# Everything below this shouldn't be modified.

BACKGROUND=${BACKGROUND:-1}

# Inform user if eula.txt not found.
if [ ! -f eula.txt ]; then
  echo "Missing eula.txt. Startup will fail and eula.txt will be created"
  echo "Make sure to read eula.txt before playing!"
  BACKGROUND=0
else
  # Check if they have accepted the eula.
  if grep -q 'eula=false' eula.txt; then
    echo "Make sure to read eula.txt before playing!"
    exit 1
  fi
fi

# Locate the server jar.
FORGE_JAR=`find . -name forge\*.jar | tail -n1`
if [ -z $FORGE_JAR ]; then
  FORGE_JAR=`find . -name FTBServer\*.jar | tail -n1`
fi
if [ -z $FORGE_JAR ]; then
  echo $FORGE_JAR
  echo "No server jar found. Can not continue."
  echo "Supported jar files match the pattern forge*.jar or FTBServer*.jar."
  exit 1
fi

# Command to start the server.
INVOKE="java ${MEMORY_OPTS} ${JAVA_OPTIONS} ${JMX_OPTIONS} -jar $FORGE_JAR nogui 2>&1 | tee minecraft.log"

# Build screen session name.
PACKNAME=`pwd | cut -d'/' -f4`
SCREEN_SESSION=$PACKNAME

# Write startup script.
write_script() {
  echo $INVOKE > $CONTROL_SCRIPT
  chmod u+x $CONTROL_SCRIPT
}

##
# Start the server.
#
cl_start() {
  if [ $BACKGROUND -eq 1 ]; then
    if ! screen -list | grep -q $SCREEN_SESSION; then
      echo "Starting Server in background"
      write_script
      screen -dmS $SCREEN_SESSION ./$CONTROL_SCRIPT
      sleep 1
      if ! screen -list | grep -q $SCREEN_SESSION; then
        cat minecraft.log
        echo ""
        echo "Server failed to start!"
        exit 1
      fi
      echo "Successfully started server"
    else
      echo "Server already started."
      exit
    fi
  else
    write_script
    ./$CONTROL_SCRIPT
  fi

}

##
# Stop the server.
cl_stop() {
  if ! screen -list | grep -q $SCREEN_SESSION; then
    exit
  fi
  echo 'Saving...'
  screen -p 0 -S $SCREEN_SESSION -X eval 'stuff "say SERVER SHUTTING DOWN IN 10 SECONDS. Saving map..."\015'
  screen -p 0 -S $SCREEN_SESSION -X eval 'stuff "save-all"\015'
  sleep 10
  echo 'Stopping'
  screen -p 0 -S $SCREEN_SESSION -X eval 'stuff "stop"\015'
  sleep 3
}

while [ "$1" != "" ]; do
  case $1 in
    --start )
      cl_start
      ;;
    -s | --stop )
      cl_stop
      exit
      ;;
    * )
      echo "Give me a command. --start or --stop"
      ;;
  esac
  shift
done