Java And Minecraft

2012-08-13

Java, and therefore Minecraft, have a shitty habit of breaking (certainly consistently for me) with random things as non rendering textures, missing polygons and the dreaded "white screen of death" on Minecraft bootup.

On top of that the technic launcher (which is a great tool) doesn't appear to work well with the standard JRE from the Arch Linux repos. It doesn't appear to define a main class and so java just breaks with a fatal error. To fix that you need to launch the jar file with a specific class loading.

I created this really quick and dirty script (not fully tested) to move the current tekkit folder to a backup area and then redownload it.

Edit: Updated the script to provide better basic functions, including an option to restore from a backup.

#!/bin/bash
switch=${1,,}

# General variables
technicDir="~/.techniclauncher"
curDate=$(date +%d+m+y)
curDir="$technicDir/tekkit"

cleDir () {
        oldDate=$(date --date="-"$old"days" +%d%m%y)
        oldDir="$technicDir/backup/$oldDate"
        for old in $(seq 7 28); do      # Checks for three weeks of backups
                if [ -d "$oldDir" ]; then       # Check if the old backup exist
                        rm -rf $oldDir  # Removes oldest 2 weeks
                fi
        done
        echo "Old backups pruned."
}

bakDir () {
        if [ -d "$curDir" ]; then       # Check the tekkit folder exists
                cp -R $technicDir/tekkit $technicDir/backup/$curDate
        else
                echo "No Tekkit folder found, chances are it's already backed up."
                exit 0
        fi
}

resDir () {
        usrDate=$2      # Get the date to restore
        if [ -d "$resDir" ]; then       # Check the backup exists
                $resDir="$technicDir/backup/$usrDate"
                bakDir  # Backup current directory first
                cp -R $resDir $curDir   # Copy the backup to the real tekkit folder
        else
                echo "Backup from date selected not found!"
                exit 0
        fi
}

playGame () {
        # Run the technic launcher (change memory as required)
        LD_LIBRARY_PATH="$LD_LIBRARY_PATH:$JAVA_HOME/lib/amd64/:$JAVA_HOME/lib/i386/:$JAVA_HOME/jre/lib/amd64/:$JAVA_HOME/jre/lib/i386/"
	# Change paths as required
        exec /opt/java/jre/bin/java -Xmx4096M -Xms4096M -cp /opt/games/technic/technic.jar org.spoutcraft.launcher.Main $@
}

showHelp () {
        echo -e "-b --backup\t\tBackup the currently active Tekkit folder"
        echo -e "-r --restore\t\tRestore a backup from a set date [DDMMYY]"
        echo -e "-p --play\t\tPlay the gme!"
        echo -e "Anthing else will show this help message."
}

# Switch checking
if [[ $switch == "-b" || $switch == "--backup" ]]; then
        cleDir
        bakDir
        exit 0 
elif [[ $switch == "-r" || $switch == "--restore" ]]; then
        resDir
        exit 0 
elif [[ $switch == "-p" || $switch == "--play" ]]; then
        playGame
        exit 0 
else
        showHelp
        exit 0 
fi