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PYTHON(1) User Commands PYTHON(1)


Python - manual page for vtkPython 3.9.0+ : VTK-Wrapper for Python


usage: /usr/bin/../lib/x86_64-linux-gnu/vtkpython [option] ... [-c cmd | -m mod | file | -] [arg] ... Options and arguments (and corresponding environment variables): -b : issue warnings about str(bytes_instance), str(bytearray_instance)
and comparing bytes/bytearray with str. (-bb: issue errors)

-B : don't write .pyc 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

-I : isolate Python from the user's environment (implies -E and -s) -m mod : run library module as a script (terminates option list) -O : remove assert and __debug__-dependent statements; add .opt-1 before

.pyc extension; also PYTHONOPTIMIZE=x

-OO : do -O changes and also discard docstrings; add .opt-2 before

.pyc extension

-q : don't print version and copyright messages on interactive startup -s : don't add user site directory to sys.path; also PYTHONNOUSERSITE -S : don't imply 'import site' on initialization -u : force the stdout and stderr streams to be unbuffered;

this option has no effect on stdin; also PYTHONUNBUFFERED=x

-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)

when given twice, print more information about the build

-W arg : warning control; arg is action:message:category:module:lineno


-x : skip first line of source, allowing use of non-Unix forms of #!cmd -X opt : set implementation-specific option. The following options are available:

-X faulthandler: enable faulthandler

-X oldparser: enable the traditional LL(1) parser; also PYTHONOLDPARSER

-X showrefcount: output the total reference count and number of used

memory blocks when the program finishes or after each statement in the interactive interpreter. This only works on debug builds

-X tracemalloc: start tracing Python memory allocations using the

tracemalloc module. By default, only the most recent frame is stored in a traceback of a trace. Use -X tracemalloc=NFRAME to start tracing with a traceback limit of NFRAME frames

-X importtime: show how long each import takes. It shows module name,

cumulative time (including nested imports) and self time (excluding nested imports). Note that its output may be broken in multi-threaded application. Typical usage is python3 -X importtime -c 'import asyncio'

-X dev: enable CPython's "development mode", introducing additional runtime

checks which are too expensive to be enabled by default. Effect of the developer mode:
* Add default warning filter, as -W default * Install debug hooks on memory allocators: see the PyMem_SetupDebugHooks() C function * Enable the faulthandler module to dump the Python traceback on a crash * Enable asyncio debug mode * Set the dev_mode attribute of sys.flags to True * io.IOBase destructor logs close() exceptions

-X utf8: enable UTF-8 mode for operating system interfaces, overriding the default

locale-aware mode. -X utf8=0 explicitly disables UTF-8 mode (even when it would otherwise activate automatically)

-X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted at the

given directory instead of to the code tree

--check-hash-based-pycs always|default|never:

control how Python invalidates hash-based .pyc files

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 <prefix>/lib/pythonX.X.

PYTHONPLATLIBDIR : override sys.platlibdir. PYTHONCASEOK : ignore case in 'import' statements (Windows). PYTHONUTF8: if set to 1, enable the UTF-8 mode. PYTHONIOENCODING: Encoding[:errors] used for stdin/stdout/stderr. PYTHONFAULTHANDLER: dump the Python traceback on fatal errors. PYTHONHASHSEED: if this variable is set to 'random', a random value is used

to seed the hashes of str and bytes objects.
It can also be set to an
integer in the range [0,4294967295] to get hash values with a predictable seed.

PYTHONMALLOC: set the Python memory allocators and/or install debug hooks

on Python memory allocators. Use PYTHONMALLOC=debug to install debug hooks.

PYTHONCOERCECLOCALE: if this variable is set to 0, it disables the locale

coercion behavior. Use PYTHONCOERCECLOCALE=warn to request display of locale coercion and locale compatibility warnings on stderr.

PYTHONBREAKPOINT: if this variable is set to 0, it disables the default

debugger. It can be set to the callable of your debugger of choice.

PYTHONDEVMODE: enable the development mode. PYTHONPYCACHEPREFIX: root directory for bytecode cache (pyc) files.


The full documentation for Python is maintained as a Texinfo manual. If the info and Python programs are properly installed at your site, the command
info Python

should give you access to the complete manual.

November 2020 Python 3.9.0+