# The name of the executed script is at the beginning of the argv list.
print('usage:', sys.argv[0], '<filename> <start> <end>')
# You can use it to generate the path prefix of the executed program
# (as opposed to the current module) to access files relative to that,
# which would be good for assets of a game, for instance.
program_file = sys.argv[0]
import pathlib
program_path = pathlib.Path(program_file).resolve().parent