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My Thoughts, Trials and Adventures

They are Billions - Automatic game saving utility

Posted at — Aug 9, 2020 | Last Modified on — May 11, 2023

Github repository


technical overview of TRBSG. the purpose of the tool is to automatically backup(zip) save files of They are Billions and easily restore them afterward.


  • start from anytime the game is saved.
  • easy to restore (-r)


save directory is by default set to C:\\Users\{user}\Documents\My Games\They Are Billions\. non-default value can be passed using --path arg.

This is a small script(< 80 ln) written in python (>= 3.0). this script repeatedly checks for a change in modified date of files ending with *zx* file extension as an indication that savefiles are modified.

def watch(path):
    print("Watching: ", path)

    modified_times = []
    for root, _, files in os.walk(path):
        for file in files:
            if ".zx" in file:
                modified_times.append(os.path.getmtime(os.path.join(root, file)))

    while True:
        current_modified_times = []

        for root, _, files in os.walk(path):
            for file in files:
                if ".zx" in file:
                        current_modified_times.append(os.path.getmtime(os.path.join(root, file)))
                    except FileNotFoundError:

        if current_modified_times != modified_times:
            print(modified_times, current_modified_times)
            modified_times = current_modified_times


1st loop stores the initial modified time of files in a list. this is later compared every time in an infinite loop to check for a change in the modified timestamp. if any change is detected, it calls zipSave(path) and sets modified_times = current_modified_times

zipSave() uses shutil.make_archive() to make zip file and store it under saves/

def zipSave(path):
    zipfname = "saves\\{n}".format(n=len(os.listdir("saves"))+1)
    shutil.make_archive(zipfname, 'zip', path)
    print("Backup completed ", zipfname)

the user has 2 option to restore the backup(s),

  1. extract zip file directly to save directory, relacing files. (or)
  2. use -r option



this is a very simple script to backup your progress in the game and restart conveniently. this makes playing ‘They are Billions’ a bit easier. 😊