speed.sh

#!/bin/sh

# This script is expected to be run from the .minecraft directory.
# Go into the saves directory, since everything will based on the world
# directories which can be found there
cd saves

# Obtain an array of all saves

saveFiles=(*)

if [ -z $1 ] ; then
    # No arguments was provided, ask the user to choose a world
    echo "Please choose a world by running ./speed num"
    echo "For example, to use the first world do ./speed 1"

    # Print a world list
    saveNum=0
    for save in "${saveFiles[@]}" ; do
        echo ${saveNum}: ${save}

        saveNum=$((saveNum+1))
    done

else
    # The first argument should a world number.
    # Go into the stats folder for the world the user chose.

    cd "${saveFiles[$1]}"
    cd stats

    # There should only be one .json file, so doing *.json should
    # only return the contents of one file.

    echo "hh:mm:ss:ff"

    while : ; do

        # You are looking for the playOneMinute stat inside of the file

        ticks=$(cat *.json | grep -Po '(?<=playOneMinute\":)[0-9]*')

        # Calculate hours
        hours=$(expr $ticks / 20 / 60 / 60)

        # Calculate minutes
        hoursInTicks=$(expr $hours \* 20 \* 60 \* 60)
        ticksLeftForMinutes=$(expr $ticks - $hoursInTicks)
        minutes=$(expr $ticksLeftForMinutes / 20 / 60)

        # Calculate seconds
        minutesInTicks=$(expr $minutes \* 20 \* 60)
        ticksLeftForSeconds=$(expr $ticks - $hoursInTicks - $minutesInTicks)
        seconds=$(expr $ticksLeftForSeconds / 20)

        # Calculate hundereth of seconds
        secondsInTicks=$(expr $seconds \* 20)
        ticksLeftForHundereth=$(expr $ticks - $hoursInTicks - $minutesInTicks - $secondsInTicks)
        # Bash has no support for fractions - a tick is 1/20 of a seconds, so multiplying
        # by 5 gives us one hundereth
        hundereth=$(expr $ticksLeftForHundereth \* 5)

        # Format the time string
        time=$(printf "%02d:%02d:%02d:%02d" $hours $minutes $seconds $hundereth)
        

        # Output the result to the console and a textfile
        echo $time
        echo $time > ../../../time.txt

        # Use inotify to wait until the json file is resaved. It might
        # not be installed by default on all systems. As an alternative
        # you might want to just check every X milliseconds.

        inotifywait -qq *.json

    done
fi