1. 命令列與環境¶
The CPython interpreter scans the command line and the environment for various settings.
CPython 實作細節： Other implementations' command line schemes may differ. See 可選實作 for further resources.
1.1. 命令列¶
When invoking Python, you may specify any of these options:
python [-bBdEhiIOPqRsSuvVWx?] [-c command | -m module-name | script | - ] [args]
The most common use case is, of course, a simple invocation of a script:
python myscript.py
1.1.1. 介面選項¶
The interpreter interface resembles that of the UNIX shell, but provides some additional methods of invocation:
When called with standard input connected to a tty device, it prompts for commands and executes them until an EOF (an end-of-file character, you can produce that with Ctrl-D on UNIX or Ctrl-Z, Enter on Windows) is read. For more on interactive mode, see 互動模式.
When called with a file name argument or with a file as standard input, it reads and executes a script from that file.
When called with a directory name argument, it reads and executes an appropriately named script from that directory.
When called with
-c command, it executes the Python statement(s) given as command. Here command may contain multiple statements separated by newlines. Leading whitespace is significant in Python statements!When called with
-m module-name, the given module is located on the Python module path and executed as a script.
In non-interactive mode, the entire input is parsed before it is executed.
An interface option terminates the list of options consumed by the interpreter,
all consecutive arguments will end up in sys.argv -- note that the first
element, subscript zero (sys.argv[0]), is a string reflecting the program's
source.
- -c <command>¶
Execute the Python code in command. command can be one or more statements separated by newlines, with significant leading whitespace as in normal module code.
If this option is given, the first element of
sys.argvwill be"-c"and the current directory will be added to the start ofsys.path(allowing modules in that directory to be imported as top level modules).引發一個附帶引數
command的稽核事件cpython.run_command。在 3.14 版的變更: command is automatically dedented before execution.
- -m <module-name>¶
Search
sys.pathfor the named module and execute its contents as the__main__module.Since the argument is a module name, you must not give a file extension (
.py). The module name should be a valid absolute Python module name, but the implementation may not always enforce this (e.g. it may allow you to use a name that includes a hyphen).Package names (including namespace packages) are also permitted. When a package name is supplied instead of a normal module, the interpreter will execute
<pkg>.__main__as the main module. This behaviour is deliberately similar to the handling of directories and zipfiles that are passed to the interpreter as the script argument.備註
This option cannot be used with built-in modules and extension modules written in C, since they do not have Python module files. However, it can still be used for precompiled modules, even if the original source file is not available.
If this option is given, the first element of
sys.argvwill be the full path to the module file (while the module file is being located, the first element will be set to"-m"). As with the-coption, the current directory will be added to the start ofsys.path.-Ioption can be used to run the script in isolated mode wheresys.pathcontains neither the current directory nor the user's site-packages directory. AllPYTHON*environment variables are ignored, too.Many standard library modules contain code that is invoked on their execution as a script. An example is the
timeitmodule:python -m timeit -s "setup here" "benchmarked code here" python -m timeit -h # for details
引發一個附帶引數
module-name的稽核事件cpython.run_module。也參考
runpy.run_module()Equivalent functionality directly available to Python code
PEP 338 -- Executing modules as scripts
在 3.1 版的變更: Supply the package name to run a
__main__submodule.在 3.4 版的變更: namespace packages are also supported
- -
Read commands from standard input (
sys.stdin). If standard input is a terminal,-iis implied.If this option is given, the first element of
sys.argvwill be"-"and the current directory will be added to the start ofsys.path.引發一個不附帶引數的稽核事件
cpython.run_stdin。
- <script>
Execute the Python code contained in script, which must be a filesystem path (absolute or relative) referring to either a Python file, a directory containing a
__main__.pyfile, or a zipfile containing a__main__.pyfile.If this option is given, the first element of
sys.argvwill be the script name as given on the command line.If the script name refers directly to a Python file, the directory containing that file is added to the start of
sys.path, and the file is executed as the__main__module.If the script name refers to a directory or zipfile, the script name is added to the start of
sys.pathand the__main__.pyfile in that location is executed as the__main__module.-Ioption can be used to run the script in isolated mode wheresys.pathcontains neither the script's directory nor the user's site-packages directory. AllPYTHON*environment variables are ignored, too.引發一個附帶引數
filename的稽核事件cpython.run_file。也參考
runpy.run_path()Equivalent functionality directly available to Python code
If no interface option is given, -i is implied, sys.argv[0] is
an empty string ("") and the current directory will be added to the
start of sys.path. Also, tab-completion and history editing is
automatically enabled, if available on your platform (see
Readline configuration).
也參考
在 3.4 版的變更: Automatic enabling of tab-completion and history editing.
1.1.2. Generic options¶
- -?¶
- -h¶
- --help¶
Print a short description of all command line options and corresponding environment variables and exit.
- --help-env¶
Print a short description of Python-specific environment variables and exit.
在 3.11 版被加入.
- --help-all¶
印出完整使用資訊並離開。
在 3.11 版被加入.
1.1.3. Miscellaneous options¶
- -b¶
Issue a warning when converting
bytesorbytearraytostrwithout specifying encoding or comparingbytesorbytearraywithstrorbyteswithint. Issue an error when the option is given twice (-bb).