【Python】「Python」を対話モードで使用する方法

「Python」コマンドは、対話モード （インタラクティブ実行モード）もある。

-B	don't write .py[co] files on import; also PYTHONDONTWRITEBYTECODE=x
-c cmd	program passed in as string (terminates option list)
-d	debug output from parser; also PYTHONDEBUG=x
-E	ignore PYTHON* environment variables (such as PYTHONPATH)
-h	print this help message and exit (also --help)
-i	inspect interactively after running script; forces a prompt even. if stdin does not appear to be a terminal; also PYTHONINSPECT=x
-m mod : run library module as a script (terminates option list)
-O	optimize generated bytecode slightly; also PYTHONOPTIMIZE=x
-OO	remove doc-strings in addition to the -O optimizations
-R	use a pseudo-random salt to make hash() values of various types be unpredictable between separate invocations of the interpreter, as a defense against denial-of-service attacks
-Q arg	division options: -Qold (default), -Qwarn, -Qwarnall, -Qnew
-s	don't add user site directory to sys.path; also PYTHONNOUSERSITE
-S	don't imply 'import site' on initialization
-t	issue warnings about inconsistent tab usage (-tt: issue errors)
-u	unbuffered binary stdout and stderr; also PYTHONUNBUFFERED=x see man page for details on internal buffering relating to '-u'
-v	verbose (trace import statements); also PYTHONVERBOSE=x can be supplied multiple times to increase verbosity
-V	print the Python version number and exit (also --version)
-W arg : warning control; arg is action:message:category:module:lineno also PYTHONWARNINGS=arg
-x	skip first line of source, allowing use of non-Unix forms of #!cmd
-3	warn about Python 3.x incompatibilities that 2to3 cannot trivially fix
file	program read from script file
-	program read from stdin (default; interactive mode if a tty)
arg ...:	arguments passed to program in sys.argv[1:]

Other environment variables:

PYTHONSTARTUP	file executed on interactive startup (no default)
PYTHONPATH	':'-separated list of directories prefixed to the default module search path. The result is sys.path.
PYTHONHOME	alternate <prefix> directory (or <prefix>:<exec_prefix>). The default module search path uses /pythonX.X.
PYTHONCASEOK	ignore case in 'import' statements (Windows).
PYTHONIOENCODING	Encoding[:errors] used for stdin/stdout/stderr.
PYTHONHASHSEED	if this variable is set to 'random', the effect is the same as specifying the -R option: a random value is used to seed the hashes of str, bytes and datetime objects. It can also be set to an integer in the range [0,4294967295] to get hash values with a predictable seed.