Berker Peksag | 3e1c823 | 2014-12-10 02:07:08 +0200 | [diff] [blame] | 1 | .. highlightlang:: sh |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 2 | |
Benjamin Peterson | f3a8c66 | 2010-04-06 23:32:27 +0000 | [diff] [blame] | 3 | .. ATTENTION: You probably should update Misc/python.man, too, if you modify |
Berker Peksag | 3e1c823 | 2014-12-10 02:07:08 +0200 | [diff] [blame] | 4 | this file. |
Benjamin Peterson | f3a8c66 | 2010-04-06 23:32:27 +0000 | [diff] [blame] | 5 | |
Georg Brandl | 87983f2 | 2007-12-01 23:12:45 +0000 | [diff] [blame] | 6 | .. _using-on-general: |
| 7 | |
Georg Brandl | 1cddfed | 2007-10-20 18:33:20 +0000 | [diff] [blame] | 8 | Command line and environment |
| 9 | ============================ |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 10 | |
| 11 | The CPython interpreter scans the command line and the environment for various |
| 12 | settings. |
| 13 | |
Georg Brandl | 6c14e58 | 2009-10-22 11:48:10 +0000 | [diff] [blame] | 14 | .. impl-detail:: |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 15 | |
Georg Brandl | cbcfe4f | 2007-12-03 19:57:02 +0000 | [diff] [blame] | 16 | Other implementations' command line schemes may differ. See |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 17 | :ref:`implementations` for further resources. |
| 18 | |
| 19 | |
Georg Brandl | 87983f2 | 2007-12-01 23:12:45 +0000 | [diff] [blame] | 20 | .. _using-on-cmdline: |
| 21 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 22 | Command line |
| 23 | ------------ |
| 24 | |
| 25 | When invoking Python, you may specify any of these options:: |
| 26 | |
Zachary Ware | f6c6d1e | 2017-05-13 09:30:20 -0500 | [diff] [blame^] | 27 | python [-bBdEiOQsRStuUvVWxX3?] [-c command | -m module-name | script | - ] [args] |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 28 | |
| 29 | The most common use case is, of course, a simple invocation of a script:: |
| 30 | |
| 31 | python myscript.py |
| 32 | |
| 33 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 34 | .. _using-on-interface-options: |
| 35 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 36 | Interface options |
| 37 | ~~~~~~~~~~~~~~~~~ |
| 38 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 39 | The interpreter interface resembles that of the UNIX shell, but provides some |
| 40 | additional methods of invocation: |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 41 | |
| 42 | * When called with standard input connected to a tty device, it prompts for |
| 43 | commands and executes them until an EOF (an end-of-file character, you can |
Serhiy Storchaka | 9b2e37f | 2015-09-12 17:47:12 +0300 | [diff] [blame] | 44 | produce that with :kbd:`Ctrl-D` on UNIX or :kbd:`Ctrl-Z, Enter` on Windows) is read. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 45 | * When called with a file name argument or with a file as standard input, it |
| 46 | reads and executes a script from that file. |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 47 | * When called with a directory name argument, it reads and executes an |
| 48 | appropriately named script from that directory. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 49 | * When called with ``-c command``, it executes the Python statement(s) given as |
| 50 | *command*. Here *command* may contain multiple statements separated by |
| 51 | newlines. Leading whitespace is significant in Python statements! |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 52 | * When called with ``-m module-name``, the given module is located on the |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 53 | Python module path and executed as a script. |
| 54 | |
| 55 | In non-interactive mode, the entire input is parsed before it is executed. |
| 56 | |
| 57 | An interface option terminates the list of options consumed by the interpreter, |
| 58 | all consecutive arguments will end up in :data:`sys.argv` -- note that the first |
| 59 | element, subscript zero (``sys.argv[0]``), is a string reflecting the program's |
| 60 | source. |
| 61 | |
| 62 | .. cmdoption:: -c <command> |
| 63 | |
Georg Brandl | 90c0718 | 2010-07-07 19:09:12 +0000 | [diff] [blame] | 64 | Execute the Python code in *command*. *command* can be one or more |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 65 | statements separated by newlines, with significant leading whitespace as in |
| 66 | normal module code. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 67 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 68 | If this option is given, the first element of :data:`sys.argv` will be |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 69 | ``"-c"`` and the current directory will be added to the start of |
| 70 | :data:`sys.path` (allowing modules in that directory to be imported as top |
| 71 | level modules). |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 72 | |
| 73 | |
| 74 | .. cmdoption:: -m <module-name> |
| 75 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 76 | Search :data:`sys.path` for the named module and execute its contents as |
| 77 | the :mod:`__main__` module. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 78 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 79 | Since the argument is a *module* name, you must not give a file extension |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 80 | (``.py``). The ``module-name`` should be a valid Python module name, but |
| 81 | the implementation may not always enforce this (e.g. it may allow you to |
| 82 | use a name that includes a hyphen). |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 83 | |
Nick Coghlan | d39600e | 2009-02-08 01:26:34 +0000 | [diff] [blame] | 84 | Package names are also permitted. When a package name is supplied instead |
| 85 | of a normal module, the interpreter will execute ``<pkg>.__main__`` as |
| 86 | the main module. This behaviour is deliberately similar to the handling |
| 87 | of directories and zipfiles that are passed to the interpreter as the |
| 88 | script argument. |
| 89 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 90 | .. note:: |
| 91 | |
Georg Brandl | d7d4fd7 | 2009-07-26 14:37:28 +0000 | [diff] [blame] | 92 | This option cannot be used with built-in modules and extension modules |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 93 | written in C, since they do not have Python module files. However, it |
| 94 | can still be used for precompiled modules, even if the original source |
| 95 | file is not available. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 96 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 97 | If this option is given, the first element of :data:`sys.argv` will be the |
Nick Coghlan | 8842c35 | 2010-06-13 06:50:39 +0000 | [diff] [blame] | 98 | full path to the module file. As with the :option:`-c` option, the current |
| 99 | directory will be added to the start of :data:`sys.path`. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 100 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 101 | Many standard library modules contain code that is invoked on their execution |
| 102 | as a script. An example is the :mod:`timeit` module:: |
| 103 | |
| 104 | python -mtimeit -s 'setup here' 'benchmarked code here' |
| 105 | python -mtimeit -h # for details |
| 106 | |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 107 | .. seealso:: |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 108 | :func:`runpy.run_module` |
Nick Coghlan | d39600e | 2009-02-08 01:26:34 +0000 | [diff] [blame] | 109 | Equivalent functionality directly available to Python code |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 110 | |
| 111 | :pep:`338` -- Executing modules as scripts |
| 112 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 113 | .. versionadded:: 2.4 |
| 114 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 115 | .. versionchanged:: 2.5 |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 116 | The named module can now be located inside a package. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 117 | |
Nick Coghlan | d39600e | 2009-02-08 01:26:34 +0000 | [diff] [blame] | 118 | .. versionchanged:: 2.7 |
| 119 | Supply the package name to run a ``__main__`` submodule. |
Nick Coghlan | ad709ee | 2010-04-28 14:53:59 +0000 | [diff] [blame] | 120 | sys.argv[0] is now set to ``"-m"`` while searching for the module |
| 121 | (it was previously incorrectly set to ``"-c"``) |
Nick Coghlan | d39600e | 2009-02-08 01:26:34 +0000 | [diff] [blame] | 122 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 123 | |
| 124 | .. describe:: - |
| 125 | |
| 126 | Read commands from standard input (:data:`sys.stdin`). If standard input is |
| 127 | a terminal, :option:`-i` is implied. |
| 128 | |
| 129 | If this option is given, the first element of :data:`sys.argv` will be |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 130 | ``"-"`` and the current directory will be added to the start of |
| 131 | :data:`sys.path`. |
| 132 | |
Berker Peksag | 3e1c823 | 2014-12-10 02:07:08 +0200 | [diff] [blame] | 133 | .. seealso:: |
| 134 | :func:`runpy.run_path` |
| 135 | Equivalent functionality directly available to Python code |
| 136 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 137 | |
| 138 | .. describe:: <script> |
| 139 | |
| 140 | Execute the Python code contained in *script*, which must be a filesystem |
| 141 | path (absolute or relative) referring to either a Python file, a directory |
| 142 | containing a ``__main__.py`` file, or a zipfile containing a |
| 143 | ``__main__.py`` file. |
| 144 | |
| 145 | If this option is given, the first element of :data:`sys.argv` will be the |
| 146 | script name as given on the command line. |
| 147 | |
| 148 | If the script name refers directly to a Python file, the directory |
| 149 | containing that file is added to the start of :data:`sys.path`, and the |
| 150 | file is executed as the :mod:`__main__` module. |
| 151 | |
| 152 | If the script name refers to a directory or zipfile, the script name is |
| 153 | added to the start of :data:`sys.path` and the ``__main__.py`` file in |
| 154 | that location is executed as the :mod:`__main__` module. |
| 155 | |
| 156 | .. versionchanged:: 2.5 |
| 157 | Directories and zipfiles containing a ``__main__.py`` file at the top |
| 158 | level are now considered valid Python scripts. |
| 159 | |
| 160 | If no interface option is given, :option:`-i` is implied, ``sys.argv[0]`` is |
| 161 | an empty string (``""``) and the current directory will be added to the |
| 162 | start of :data:`sys.path`. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 163 | |
Georg Brandl | 14da8e8 | 2008-11-07 08:27:39 +0000 | [diff] [blame] | 164 | .. seealso:: :ref:`tut-invoking` |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 165 | |
| 166 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 167 | Generic options |
| 168 | ~~~~~~~~~~~~~~~ |
| 169 | |
| 170 | .. cmdoption:: -? |
| 171 | -h |
| 172 | --help |
| 173 | |
| 174 | Print a short description of all command line options. |
| 175 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 176 | .. versionchanged:: 2.5 |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 177 | The ``--help`` variant. |
| 178 | |
| 179 | |
| 180 | .. cmdoption:: -V |
| 181 | --version |
| 182 | |
| 183 | Print the Python version number and exit. Example output could be:: |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 184 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 185 | Python 2.5.1 |
| 186 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 187 | .. versionchanged:: 2.5 |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 188 | The ``--version`` variant. |
| 189 | |
| 190 | |
| 191 | Miscellaneous options |
| 192 | ~~~~~~~~~~~~~~~~~~~~~ |
| 193 | |
Zachary Ware | f6c6d1e | 2017-05-13 09:30:20 -0500 | [diff] [blame^] | 194 | .. cmdoption:: -b |
| 195 | |
| 196 | Issue a warning when comparing :class:`unicode` with :class:`bytearray`. |
| 197 | Issue an error when the option is given twice (:option:`!-bb`). |
| 198 | |
| 199 | Note that, unlike the corresponding Python 3.x flag, this will **not** emit |
| 200 | warnings for comparisons between :class:`str` and :class:`unicode`. |
| 201 | Instead, the ``str`` instance will be implicitly decoded to ``unicode`` and |
| 202 | Unicode comparison used. |
| 203 | |
| 204 | .. versionadded:: 2.6 |
| 205 | |
| 206 | |
Georg Brandl | 2da0fce | 2008-01-07 17:09:35 +0000 | [diff] [blame] | 207 | .. cmdoption:: -B |
| 208 | |
| 209 | If given, Python won't try to write ``.pyc`` or ``.pyo`` files on the |
| 210 | import of source modules. See also :envvar:`PYTHONDONTWRITEBYTECODE`. |
| 211 | |
| 212 | .. versionadded:: 2.6 |
| 213 | |
| 214 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 215 | .. cmdoption:: -d |
| 216 | |
| 217 | Turn on parser debugging output (for wizards only, depending on compilation |
| 218 | options). See also :envvar:`PYTHONDEBUG`. |
| 219 | |
| 220 | |
| 221 | .. cmdoption:: -E |
| 222 | |
Georg Brandl | c5004f3 | 2007-10-20 19:05:45 +0000 | [diff] [blame] | 223 | Ignore all :envvar:`PYTHON*` environment variables, e.g. |
Georg Brandl | 3507333 | 2007-10-20 19:08:36 +0000 | [diff] [blame] | 224 | :envvar:`PYTHONPATH` and :envvar:`PYTHONHOME`, that might be set. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 225 | |
Georg Brandl | c5004f3 | 2007-10-20 19:05:45 +0000 | [diff] [blame] | 226 | .. versionadded:: 2.2 |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 227 | |
| 228 | |
| 229 | .. cmdoption:: -i |
| 230 | |
| 231 | When a script is passed as first argument or the :option:`-c` option is used, |
| 232 | enter interactive mode after executing the script or the command, even when |
| 233 | :data:`sys.stdin` does not appear to be a terminal. The |
| 234 | :envvar:`PYTHONSTARTUP` file is not read. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 235 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 236 | This can be useful to inspect global variables or a stack trace when a script |
| 237 | raises an exception. See also :envvar:`PYTHONINSPECT`. |
| 238 | |
| 239 | |
Martin Panter | 39d74a9 | 2016-10-30 05:41:04 +0000 | [diff] [blame] | 240 | .. _using-on-optimizations: |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 241 | .. cmdoption:: -O |
| 242 | |
| 243 | Turn on basic optimizations. This changes the filename extension for |
Georg Brandl | 5e52db0 | 2007-10-21 10:45:46 +0000 | [diff] [blame] | 244 | compiled (:term:`bytecode`) files from ``.pyc`` to ``.pyo``. See also |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 245 | :envvar:`PYTHONOPTIMIZE`. |
| 246 | |
| 247 | |
| 248 | .. cmdoption:: -OO |
| 249 | |
| 250 | Discard docstrings in addition to the :option:`-O` optimizations. |
| 251 | |
| 252 | |
| 253 | .. cmdoption:: -Q <arg> |
| 254 | |
| 255 | Division control. The argument must be one of the following: |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 256 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 257 | ``old`` |
| 258 | division of int/int and long/long return an int or long (*default*) |
| 259 | ``new`` |
| 260 | new division semantics, i.e. division of int/int and long/long returns a |
| 261 | float |
| 262 | ``warn`` |
| 263 | old division semantics with a warning for int/int and long/long |
| 264 | ``warnall`` |
| 265 | old division semantics with a warning for all uses of the division operator |
| 266 | |
| 267 | .. seealso:: |
| 268 | :file:`Tools/scripts/fixdiv.py` |
| 269 | for a use of ``warnall`` |
| 270 | |
| 271 | :pep:`238` -- Changing the division operator |
| 272 | |
| 273 | |
Barry Warsaw | 1e13eb0 | 2012-02-20 20:42:21 -0500 | [diff] [blame] | 274 | .. cmdoption:: -R |
| 275 | |
| 276 | Turn on hash randomization, so that the :meth:`__hash__` values of str, |
| 277 | bytes and datetime objects are "salted" with an unpredictable random value. |
| 278 | Although they remain constant within an individual Python process, they are |
| 279 | not predictable between repeated invocations of Python. |
| 280 | |
| 281 | This is intended to provide protection against a denial-of-service caused by |
| 282 | carefully-chosen inputs that exploit the worst case performance of a dict |
Georg Brandl | 3aec568 | 2012-02-21 22:36:27 +0100 | [diff] [blame] | 283 | construction, O(n^2) complexity. See |
Barry Warsaw | 1e13eb0 | 2012-02-20 20:42:21 -0500 | [diff] [blame] | 284 | http://www.ocert.org/advisories/ocert-2011-003.html for details. |
| 285 | |
| 286 | Changing hash values affects the order in which keys are retrieved from a |
| 287 | dict. Although Python has never made guarantees about this ordering (and it |
| 288 | typically varies between 32-bit and 64-bit builds), enough real-world code |
| 289 | implicitly relies on this non-guaranteed behavior that the randomization is |
| 290 | disabled by default. |
| 291 | |
| 292 | See also :envvar:`PYTHONHASHSEED`. |
| 293 | |
| 294 | .. versionadded:: 2.6.8 |
| 295 | |
| 296 | |
Christian Heimes | af748c3 | 2008-05-06 22:41:46 +0000 | [diff] [blame] | 297 | .. cmdoption:: -s |
| 298 | |
Éric Araujo | afd2fe2 | 2011-08-19 08:20:01 +0200 | [diff] [blame] | 299 | Don't add the :data:`user site-packages directory <site.USER_SITE>` to |
| 300 | :data:`sys.path`. |
Christian Heimes | af748c3 | 2008-05-06 22:41:46 +0000 | [diff] [blame] | 301 | |
| 302 | .. versionadded:: 2.6 |
| 303 | |
| 304 | .. seealso:: |
| 305 | |
| 306 | :pep:`370` -- Per user site-packages directory |
| 307 | |
| 308 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 309 | .. cmdoption:: -S |
| 310 | |
| 311 | Disable the import of the module :mod:`site` and the site-dependent |
| 312 | manipulations of :data:`sys.path` that it entails. |
| 313 | |
| 314 | |
| 315 | .. cmdoption:: -t |
| 316 | |
| 317 | Issue a warning when a source file mixes tabs and spaces for indentation in a |
| 318 | way that makes it depend on the worth of a tab expressed in spaces. Issue an |
Martin Panter | e3e362e | 2016-10-30 05:19:02 +0000 | [diff] [blame] | 319 | error when the option is given twice (:option:`!-tt`). |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 320 | |
| 321 | |
| 322 | .. cmdoption:: -u |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 323 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 324 | Force stdin, stdout and stderr to be totally unbuffered. On systems where it |
| 325 | matters, also put stdin, stdout and stderr in binary mode. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 326 | |
Georg Brandl | f4ef23f | 2007-10-30 17:51:18 +0000 | [diff] [blame] | 327 | Note that there is internal buffering in :meth:`file.readlines` and |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 328 | :ref:`bltin-file-objects` (``for line in sys.stdin``) which is not influenced |
| 329 | by this option. To work around this, you will want to use |
Georg Brandl | f4ef23f | 2007-10-30 17:51:18 +0000 | [diff] [blame] | 330 | :meth:`file.readline` inside a ``while 1:`` loop. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 331 | |
| 332 | See also :envvar:`PYTHONUNBUFFERED`. |
| 333 | |
| 334 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 335 | .. cmdoption:: -v |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 336 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 337 | Print a message each time a module is initialized, showing the place |
| 338 | (filename or built-in module) from which it is loaded. When given twice |
Martin Panter | e3e362e | 2016-10-30 05:19:02 +0000 | [diff] [blame] | 339 | (:option:`!-vv`), print a message for each file that is checked for when |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 340 | searching for a module. Also provides information on module cleanup at exit. |
| 341 | See also :envvar:`PYTHONVERBOSE`. |
| 342 | |
| 343 | |
| 344 | .. cmdoption:: -W arg |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 345 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 346 | Warning control. Python's warning machinery by default prints warning |
| 347 | messages to :data:`sys.stderr`. A typical warning message has the following |
| 348 | form:: |
| 349 | |
| 350 | file:line: category: message |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 351 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 352 | By default, each warning is printed once for each source line where it |
| 353 | occurs. This option controls how often warnings are printed. |
| 354 | |
| 355 | Multiple :option:`-W` options may be given; when a warning matches more than |
| 356 | one option, the action for the last matching option is performed. Invalid |
| 357 | :option:`-W` options are ignored (though, a warning message is printed about |
| 358 | invalid options when the first warning is issued). |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 359 | |
Ezio Melotti | 9d8d2a4 | 2010-07-03 07:43:04 +0000 | [diff] [blame] | 360 | Starting from Python 2.7, :exc:`DeprecationWarning` and its descendants |
Martin Panter | e3e362e | 2016-10-30 05:19:02 +0000 | [diff] [blame] | 361 | are ignored by default. The :option:`!-Wd` option can be used to re-enable |
Ezio Melotti | 9d8d2a4 | 2010-07-03 07:43:04 +0000 | [diff] [blame] | 362 | them. |
| 363 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 364 | Warnings can also be controlled from within a Python program using the |
| 365 | :mod:`warnings` module. |
| 366 | |
| 367 | The simplest form of argument is one of the following action strings (or a |
Brett Cannon | f31d1a0 | 2010-01-01 01:44:57 +0000 | [diff] [blame] | 368 | unique abbreviation) by themselves: |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 369 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 370 | ``ignore`` |
| 371 | Ignore all warnings. |
| 372 | ``default`` |
| 373 | Explicitly request the default behavior (printing each warning once per |
| 374 | source line). |
| 375 | ``all`` |
| 376 | Print a warning each time it occurs (this may generate many messages if a |
| 377 | warning is triggered repeatedly for the same source line, such as inside a |
| 378 | loop). |
| 379 | ``module`` |
Georg Brandl | 5a85d5c | 2009-06-24 06:41:19 +0000 | [diff] [blame] | 380 | Print each warning only the first time it occurs in each module. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 381 | ``once`` |
| 382 | Print each warning only the first time it occurs in the program. |
| 383 | ``error`` |
| 384 | Raise an exception instead of printing a warning message. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 385 | |
| 386 | The full form of argument is:: |
| 387 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 388 | action:message:category:module:line |
| 389 | |
| 390 | Here, *action* is as explained above but only applies to messages that match |
| 391 | the remaining fields. Empty fields match all values; trailing empty fields |
| 392 | may be omitted. The *message* field matches the start of the warning message |
| 393 | printed; this match is case-insensitive. The *category* field matches the |
Andrew M. Kuchling | fced908 | 2010-04-11 01:39:36 +0000 | [diff] [blame] | 394 | warning category. This must be a class name; the match tests whether the |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 395 | actual warning category of the message is a subclass of the specified warning |
| 396 | category. The full class name must be given. The *module* field matches the |
| 397 | (fully-qualified) module name; this match is case-sensitive. The *line* |
| 398 | field matches the line number, where zero matches all line numbers and is |
| 399 | thus equivalent to an omitted line number. |
| 400 | |
| 401 | .. seealso:: |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 402 | :mod:`warnings` -- the warnings module |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 403 | |
| 404 | :pep:`230` -- Warning framework |
| 405 | |
Philip Jenvey | aebbaeb | 2010-04-06 23:24:45 +0000 | [diff] [blame] | 406 | :envvar:`PYTHONWARNINGS` |
| 407 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 408 | |
| 409 | .. cmdoption:: -x |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 410 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 411 | Skip the first line of the source, allowing use of non-Unix forms of |
| 412 | ``#!cmd``. This is intended for a DOS specific hack only. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 413 | |
Georg Brandl | d91f8cf | 2009-04-27 15:10:44 +0000 | [diff] [blame] | 414 | .. note:: The line numbers in error messages will be off by one. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 415 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 416 | .. cmdoption:: -3 |
| 417 | |
Benjamin Peterson | 3690d41 | 2014-05-26 15:38:52 -0700 | [diff] [blame] | 418 | Warn about Python 3.x possible incompatibilities by emitting a |
| 419 | :exc:`DeprecationWarning` for features that are removed or significantly |
| 420 | changed in Python 3. |
Georg Brandl | 4425e7c | 2008-02-23 23:43:01 +0000 | [diff] [blame] | 421 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 422 | .. versionadded:: 2.6 |
| 423 | |
Barry Warsaw | b1e66ee | 2010-02-05 18:45:25 +0000 | [diff] [blame] | 424 | Options you shouldn't use |
| 425 | ~~~~~~~~~~~~~~~~~~~~~~~~~ |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 426 | |
Barry Warsaw | b1e66ee | 2010-02-05 18:45:25 +0000 | [diff] [blame] | 427 | .. cmdoption:: -J |
| 428 | |
| 429 | Reserved for use by Jython_. |
| 430 | |
Georg Brandl | 97ae466 | 2014-10-29 10:26:56 +0100 | [diff] [blame] | 431 | .. _Jython: http://www.jython.org/ |
Barry Warsaw | b1e66ee | 2010-02-05 18:45:25 +0000 | [diff] [blame] | 432 | |
| 433 | .. cmdoption:: -U |
| 434 | |
| 435 | Turns all string literals into unicodes globally. Do not be tempted to use |
| 436 | this option as it will probably break your world. It also produces |
| 437 | ``.pyc`` files with a different magic number than normal. Instead, you can |
| 438 | enable unicode literals on a per-module basis by using:: |
| 439 | |
| 440 | from __future__ import unicode_literals |
| 441 | |
| 442 | at the top of the file. See :mod:`__future__` for details. |
| 443 | |
| 444 | .. cmdoption:: -X |
| 445 | |
| 446 | Reserved for alternative implementations of Python to use for their own |
| 447 | purposes. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 448 | |
Georg Brandl | 87983f2 | 2007-12-01 23:12:45 +0000 | [diff] [blame] | 449 | .. _using-on-envvars: |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 450 | |
| 451 | Environment variables |
| 452 | --------------------- |
| 453 | |
Andrew Svetlov | f892597e | 2012-10-17 17:14:28 +0300 | [diff] [blame] | 454 | These environment variables influence Python's behavior, they are processed |
| 455 | before the command-line switches other than -E. It is customary that |
| 456 | command-line switches override environmental variables where there is a |
| 457 | conflict. |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 458 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 459 | .. envvar:: PYTHONHOME |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 460 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 461 | Change the location of the standard Python libraries. By default, the |
Georg Brandl | 21297fa | 2008-01-20 21:10:08 +0000 | [diff] [blame] | 462 | libraries are searched in :file:`{prefix}/lib/python{version}` and |
| 463 | :file:`{exec_prefix}/lib/python{version}`, where :file:`{prefix}` and |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 464 | :file:`{exec_prefix}` are installation-dependent directories, both defaulting |
| 465 | to :file:`/usr/local`. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 466 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 467 | When :envvar:`PYTHONHOME` is set to a single directory, its value replaces |
| 468 | both :file:`{prefix}` and :file:`{exec_prefix}`. To specify different values |
Georg Brandl | 21297fa | 2008-01-20 21:10:08 +0000 | [diff] [blame] | 469 | for these, set :envvar:`PYTHONHOME` to :file:`{prefix}:{exec_prefix}`. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 470 | |
| 471 | |
| 472 | .. envvar:: PYTHONPATH |
| 473 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 474 | Augment the default search path for module files. The format is the same as |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 475 | the shell's :envvar:`PATH`: one or more directory pathnames separated by |
Georg Brandl | 9c06574 | 2008-03-05 19:31:44 +0000 | [diff] [blame] | 476 | :data:`os.pathsep` (e.g. colons on Unix or semicolons on Windows). |
| 477 | Non-existent directories are silently ignored. |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 478 | |
| 479 | In addition to normal directories, individual :envvar:`PYTHONPATH` entries |
| 480 | may refer to zipfiles containing pure Python modules (in either source or |
| 481 | compiled form). Extension modules cannot be imported from zipfiles. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 482 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 483 | The default search path is installation dependent, but generally begins with |
Georg Brandl | fc29f27 | 2009-01-02 20:25:14 +0000 | [diff] [blame] | 484 | :file:`{prefix}/lib/python{version}` (see :envvar:`PYTHONHOME` above). It |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 485 | is *always* appended to :envvar:`PYTHONPATH`. |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 486 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 487 | An additional directory will be inserted in the search path in front of |
| 488 | :envvar:`PYTHONPATH` as described above under |
| 489 | :ref:`using-on-interface-options`. The search path can be manipulated from |
| 490 | within a Python program as the variable :data:`sys.path`. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 491 | |
| 492 | |
| 493 | .. envvar:: PYTHONSTARTUP |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 494 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 495 | If this is the name of a readable file, the Python commands in that file are |
| 496 | executed before the first prompt is displayed in interactive mode. The file |
Georg Brandl | a739503 | 2007-10-21 12:15:05 +0000 | [diff] [blame] | 497 | is executed in the same namespace where interactive commands are executed so |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 498 | that objects defined or imported in it can be used without qualification in |
| 499 | the interactive session. You can also change the prompts :data:`sys.ps1` and |
| 500 | :data:`sys.ps2` in this file. |
| 501 | |
| 502 | |
| 503 | .. envvar:: PYTHONY2K |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 504 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 505 | Set this to a non-empty string to cause the :mod:`time` module to require |
| 506 | dates specified as strings to include 4-digit years, otherwise 2-digit years |
| 507 | are converted based on rules described in the :mod:`time` module |
| 508 | documentation. |
| 509 | |
| 510 | |
| 511 | .. envvar:: PYTHONOPTIMIZE |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 512 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 513 | If this is set to a non-empty string it is equivalent to specifying the |
| 514 | :option:`-O` option. If set to an integer, it is equivalent to specifying |
| 515 | :option:`-O` multiple times. |
| 516 | |
| 517 | |
| 518 | .. envvar:: PYTHONDEBUG |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 519 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 520 | If this is set to a non-empty string it is equivalent to specifying the |
| 521 | :option:`-d` option. If set to an integer, it is equivalent to specifying |
| 522 | :option:`-d` multiple times. |
| 523 | |
| 524 | |
| 525 | .. envvar:: PYTHONINSPECT |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 526 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 527 | If this is set to a non-empty string it is equivalent to specifying the |
| 528 | :option:`-i` option. |
| 529 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 530 | This variable can also be modified by Python code using :data:`os.environ` |
| 531 | to force inspect mode on program termination. |
| 532 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 533 | |
| 534 | .. envvar:: PYTHONUNBUFFERED |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 535 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 536 | If this is set to a non-empty string it is equivalent to specifying the |
| 537 | :option:`-u` option. |
| 538 | |
| 539 | |
| 540 | .. envvar:: PYTHONVERBOSE |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 541 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 542 | If this is set to a non-empty string it is equivalent to specifying the |
| 543 | :option:`-v` option. If set to an integer, it is equivalent to specifying |
| 544 | :option:`-v` multiple times. |
| 545 | |
| 546 | |
| 547 | .. envvar:: PYTHONCASEOK |
Georg Brandl | c62ef8b | 2009-01-03 20:55:06 +0000 | [diff] [blame] | 548 | |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 549 | If this is set, Python ignores case in :keyword:`import` statements. This |
Brett Cannon | 64b2b6a | 2012-01-26 18:32:24 -0500 | [diff] [blame] | 550 | only works on Windows, OS X, OS/2, and RiscOS. |
Georg Brandl | 59d121a | 2007-10-20 18:08:14 +0000 | [diff] [blame] | 551 | |
Georg Brandl | 2da0fce | 2008-01-07 17:09:35 +0000 | [diff] [blame] | 552 | |
| 553 | .. envvar:: PYTHONDONTWRITEBYTECODE |
| 554 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 555 | If this is set, Python won't try to write ``.pyc`` or ``.pyo`` files on the |
Éric Araujo | a358bc3 | 2012-02-26 01:38:26 +0100 | [diff] [blame] | 556 | import of source modules. This is equivalent to specifying the :option:`-B` |
| 557 | option. |
Georg Brandl | 2da0fce | 2008-01-07 17:09:35 +0000 | [diff] [blame] | 558 | |
| 559 | .. versionadded:: 2.6 |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 560 | |
Barry Warsaw | 1e13eb0 | 2012-02-20 20:42:21 -0500 | [diff] [blame] | 561 | .. envvar:: PYTHONHASHSEED |
| 562 | |
| 563 | If this variable is set to ``random``, the effect is the same as specifying |
| 564 | the :option:`-R` option: a random value is used to seed the hashes of str, |
| 565 | bytes and datetime objects. |
| 566 | |
| 567 | If :envvar:`PYTHONHASHSEED` is set to an integer value, it is used as a |
| 568 | fixed seed for generating the hash() of the types covered by the hash |
| 569 | randomization. |
| 570 | |
| 571 | Its purpose is to allow repeatable hashing, such as for selftests for the |
| 572 | interpreter itself, or to allow a cluster of python processes to share hash |
| 573 | values. |
| 574 | |
| 575 | The integer must be a decimal number in the range [0,4294967295]. |
| 576 | Specifying the value 0 will lead to the same hash values as when hash |
| 577 | randomization is disabled. |
| 578 | |
| 579 | .. versionadded:: 2.6.8 |
| 580 | |
| 581 | |
Martin v. Löwis | 9981589 | 2008-06-01 07:20:46 +0000 | [diff] [blame] | 582 | .. envvar:: PYTHONIOENCODING |
| 583 | |
| 584 | Overrides the encoding used for stdin/stdout/stderr, in the syntax |
Georg Brandl | d987545 | 2008-06-11 17:57:44 +0000 | [diff] [blame] | 585 | ``encodingname:errorhandler``. The ``:errorhandler`` part is optional and |
| 586 | has the same meaning as in :func:`str.encode`. |
Martin v. Löwis | 9981589 | 2008-06-01 07:20:46 +0000 | [diff] [blame] | 587 | |
| 588 | .. versionadded:: 2.6 |
| 589 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 590 | |
Christian Heimes | af748c3 | 2008-05-06 22:41:46 +0000 | [diff] [blame] | 591 | .. envvar:: PYTHONNOUSERSITE |
| 592 | |
Éric Araujo | afd2fe2 | 2011-08-19 08:20:01 +0200 | [diff] [blame] | 593 | If this is set, Python won't add the :data:`user site-packages directory |
| 594 | <site.USER_SITE>` to :data:`sys.path`. |
Christian Heimes | af748c3 | 2008-05-06 22:41:46 +0000 | [diff] [blame] | 595 | |
| 596 | .. versionadded:: 2.6 |
| 597 | |
| 598 | .. seealso:: |
| 599 | |
| 600 | :pep:`370` -- Per user site-packages directory |
| 601 | |
| 602 | |
| 603 | .. envvar:: PYTHONUSERBASE |
| 604 | |
Éric Araujo | afd2fe2 | 2011-08-19 08:20:01 +0200 | [diff] [blame] | 605 | Defines the :data:`user base directory <site.USER_BASE>`, which is used to |
| 606 | compute the path of the :data:`user site-packages directory <site.USER_SITE>` |
Éric Araujo | e68d450 | 2011-08-19 08:34:52 +0200 | [diff] [blame] | 607 | and :ref:`Distutils installation paths <inst-alt-install-user>` for ``python |
| 608 | setup.py install --user``. |
Christian Heimes | af748c3 | 2008-05-06 22:41:46 +0000 | [diff] [blame] | 609 | |
| 610 | .. versionadded:: 2.6 |
| 611 | |
| 612 | .. seealso:: |
| 613 | |
| 614 | :pep:`370` -- Per user site-packages directory |
| 615 | |
| 616 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 617 | .. envvar:: PYTHONEXECUTABLE |
| 618 | |
| 619 | If this environment variable is set, ``sys.argv[0]`` will be set to its |
| 620 | value instead of the value got through the C runtime. Only works on |
Georg Brandl | 9af9498 | 2008-09-13 17:41:16 +0000 | [diff] [blame] | 621 | Mac OS X. |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 622 | |
Philip Jenvey | aebbaeb | 2010-04-06 23:24:45 +0000 | [diff] [blame] | 623 | .. envvar:: PYTHONWARNINGS |
| 624 | |
Andrew M. Kuchling | fced908 | 2010-04-11 01:39:36 +0000 | [diff] [blame] | 625 | This is equivalent to the :option:`-W` option. If set to a comma |
Philip Jenvey | aebbaeb | 2010-04-06 23:24:45 +0000 | [diff] [blame] | 626 | separated string, it is equivalent to specifying :option:`-W` multiple |
| 627 | times. |
| 628 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 629 | |
Nick Coghlan | dbcd457 | 2016-03-20 22:39:15 +1000 | [diff] [blame] | 630 | .. envvar:: PYTHONHTTPSVERIFY |
| 631 | |
| 632 | If this environment variable is set specifically to ``0``, then it is |
| 633 | equivalent to implicitly calling :func:`ssl._https_verify_certificates` with |
| 634 | ``enable=False`` when :mod:`ssl` is first imported. |
| 635 | |
| 636 | Refer to the documentation of :func:`ssl._https_verify_certificates` for |
| 637 | details. |
| 638 | |
| 639 | .. versionadded:: 2.7.12 |
| 640 | |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 641 | Debug-mode variables |
Georg Brandl | 61d2886 | 2008-01-07 18:57:03 +0000 | [diff] [blame] | 642 | ~~~~~~~~~~~~~~~~~~~~ |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 643 | |
| 644 | Setting these variables only has an effect in a debug build of Python, that is, |
Éric Araujo | 5cf8660 | 2011-06-09 14:26:10 +0200 | [diff] [blame] | 645 | if Python was configured with the ``--with-pydebug`` build option. |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 646 | |
| 647 | .. envvar:: PYTHONTHREADDEBUG |
| 648 | |
Nick Coghlan | 31f6315 | 2008-04-30 14:23:36 +0000 | [diff] [blame] | 649 | If set, Python will print threading debug info. |
Georg Brandl | aed6c66 | 2008-01-07 17:25:53 +0000 | [diff] [blame] | 650 | |
| 651 | .. versionchanged:: 2.6 |
| 652 | Previously, this variable was called ``THREADDEBUG``. |
| 653 | |
| 654 | .. envvar:: PYTHONDUMPREFS |
| 655 | |
| 656 | If set, Python will dump objects and reference counts still alive after |
| 657 | shutting down the interpreter. |
| 658 | |
| 659 | |
| 660 | .. envvar:: PYTHONMALLOCSTATS |
| 661 | |
| 662 | If set, Python will print memory allocation statistics every time a new |
| 663 | object arena is created, and on shutdown. |