命令列引數

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.

請注意，在較大且更精細的程式中，你可以使用諸如 click 之類的模組來處理命令列引數，而不是自己動手執行。