命令行参数

if len(sys.argv) != 4:         # The script name needs to be accounted for as well.
    raise RuntimeError("expected 3 command line arguments")

f = open(sys.argv[1], 'rb')    # Use first command line argument.
start_line = int(sys.argv[2])  # All arguments come as strings, so need to be
end_line = int(sys.argv[3])    # converted explicitly if other types are required.

请注意，在较大且更精细的程序中，你可以使用诸如 click 之类的模块来处理命令行参数，而不是自己动手执行。