def save_history():
    try:
        readline.write_history_file(c['HISTORY_FILENAME'])
    except:
        pass
Compress the data, write it to file, and add pointers in the header so it 
dataset/ETHPy150Open DTVD/rainbowstream/rainbowstream/interactive.py/save_history--crossover with--dataset/ETHPy150Open twoolie/NBT/nbt/region.py/RegionFile.write_blockdata