Minecraft Server Management Script

server.sh

#!/bin/bash

shopt -s nullglob

if [[ "$1" == '' ]]; then
    :
elif [[ "$#" -gt "1" ]]; then
    while getopts s: flag; do
        case "${flag}" in
        s)
            server=${OPTARG}
            shift
            shift
            ;;
        *)
            exit 1
            ;;
        esac
    done
    clear
else
    read -r -p "What server would you like to use: " server
fi

service="$server-Server"
startCheckDelay=15
stopCheckDelay=15
stopDelay=10
restartCheckDelay=10
serverOptions='nogui'
username='ubuntu'
serverPath="/home/ubuntu/$server"
backupPath="$serverPath/backups"
unwanted=('logs' 'cache' 'backups' 'dump' 'version_history.json' 'usercache.json' 'eula.txt' 'usernamecache.json')
maxHeap=6144
minHeap=2048

me=$(whoami)
as_user() {
    if [ "$me" == $username ]; then
        bash -c "$1"
    else
        sudo su - $username -c "$1"
    fi
}

mc_saveoff() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "$service is running, suspending saves..."
        as_user "screen -p 0 -S $service -X eval 'stuff \"say World saving paused.\"\015'"
        as_user "screen -p 0 -S $service -X eval 'stuff \"save-off\"\015'"
        as_user "screen -p 0 -S $service -X eval 'stuff \"save-all\"\015'"
        sleep 10
    else
        echo "$service is not running. Not suspending saves."
    fi
}

mc_saveon() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "$service is running, re-enabling saves..."
        as_user "screen -p 0 -S $service -X eval 'stuff \"save-on\"\015'"
        as_user "screen -p 0 -S $service -X eval 'stuff \"say World saving resumed.\"\015'"
    else
        echo "$service is not running. Not resuming saves."
    fi
}

mc_start() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "$service is already running!"
    else
        echo "Starting $service..."
        cd "$serverPath" || exit 1
        jars=(*.jar)
        if [ "${#jars[@]}" -gt 1 ]; then
            echo "Choose a server jar:"
            selections=("${jars[@]}" 'Quit')
            select serverJar in "${selections[@]}"; do
                case $serverJar in
                '')
                    echo "Invalid choice" >&2
                    ;;
                'Quit')
                    echo "Goodbye!"
                    exit
                    ;;
                *)
                    echo "You have selected: $serverJar"
                    break
                    ;;
                esac
            done
        elif [ "${#jars[@]}" -eq 1 ]; then
            serverJar="${jars[0]}"
        else
            echo "No jar found in $PWD" >&2
            exit 1
        fi
        command="java -Xmx${maxHeap}M -Xms${minHeap}M -jar $serverJar $serverOptions"
        as_user "cd $serverPath && screen -dmS $service $command"
        echo "Waiting $startCheckDelay seconds before checking if $service is running..."
        sleep $startCheckDelay
        if as_user "screen -ls | grep $service" >/dev/null; then
            echo "$service is now running."
        else
            echo "Error! Could not start $service!"
        fi
    fi
}

mc_stop() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "Notifying users $service is stopping and then waiting $stopDelay seconds..."
        as_user "screen -p 0 -S $service -X eval 'stuff \"say Server shutting down in $stopDelay seconds. Saving map...\"\015'"
        as_user "screen -p 0 -S $service -X eval 'stuff \"save-all\"\015'"
        sleep $stopDelay
        echo "Stopping $service..."
        as_user "screen -p 0 -S $service -X eval 'stuff \"stop\"\015'"
        echo "Waiting $stopCheckDelay seconds before checking if $service is stopped..."
        sleep $stopCheckDelay
    else
        echo "$service was not running."
    fi
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "Error! $service could not be stopped."
    else
        echo "$service is stopped."
    fi
}

mc_backup() {
    now=$(date "+%Y-%m-%d_%Hh%Mm")
    backupFile="$backupPath/${server}_${now}.tar"

    mc_saveoff

    cd "$serverPath" || exit
    dir=(*)

    for target in "${unwanted[@]}"; do
        for i in "${!dir[@]}"; do
            if [[ ${dir[i]} = "$target" ]]; then
                unset 'dir[i]'
            fi
        done
    done

    for i in "${!dir[@]}"; do
        updatedDir+=("${dir[i]}")
    done
    dir=("${updatedDir[@]}")
    unset updatedDir

    for i in "${dir[@]}"; do
        echo "Backing up the server ($i)..."
        as_user "tar -C $serverPath -rf $backupFile $i"
    done

    mc_saveon

    echo "Compressing backup..."
    as_user "gzip -f $backupFile"
    echo "Done."
}

mc_command() {
    command="$1"
    if as_user "screen -ls | grep $service" >/dev/null; then
        pre_log_len=$(wc -l "$server/logs/latest.log" | awk '{print $1}')
        echo "$service is running... executing command"
        as_user "screen -p 0 -S $service -X eval 'stuff \"$command\"\015'"
        sleep 5
        tail -n $(($(wc -l "$server/logs/latest.log" | awk '{print $1}') - pre_log_len)) "$server/logs/latest.log"
    else
        echo "$service is stopped."
    fi
}

mc_attach() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        as_user "screen -R $service"
    else
        echo "$service is stopped."
    fi
}

mc_detach() {
    if as_user "screen -ls | grep $service" >/dev/null; then
        as_user "screen -d $service"
    else
        echo "$service is stopped."
    fi
}

case "$1" in
start)
    mc_start
    ;;
stop)
    mc_stop
    ;;
restart)
    if as_user "screen -ls | grep $service" >/dev/null; then
        mc_stop
        echo "Waiting $restartCheckDelay before restarting..."
        sleep $restartCheckDelay
        mc_start
    else
        echo "$service is stopped."
    fi
    ;;
backup)
    mc_backup
    ;;
attach)
    mc_attach
    ;;
detach)
    mc_detach
    ;;
status)
    if as_user "screen -ls | grep $service" >/dev/null; then
        echo "$service is running."
    else
        echo "$service is not running."
    fi
    ;;
command)
    if [ $# -gt 1 ]; then
        shift
        mc_command "$*"
    else
        echo "Must specify server command (try '?')"
    fi
    ;;
*)
    echo "Usage: $0 {start|stop|backup|status|restart|attach|detach|command \"command\"}"
    exit 1
    ;;
esac

exit 0

Cool script, gonna link it in a blog post on Minelist

It may need some overwork, but its a pretty good reference :)