Provided by: python3.7-minimal_3.7.5~rc1-2_amd64 bug


       python - an interpreted, interactive, object-oriented programming language


       python [ -B ] [ -b ] [ -d ] [ -E ] [ -h ] [ -i ] [ -I ]
              [ -m module-name ] [ -q ] [ -O ] [ -OO ] [ -s ] [ -S ] [ -u ]
              [ -v ] [ -V ] [ -W argument ] [ -x ] [ [ -X option ] -?  ]
              [ --check-hash-based-pycs default | always | never ]
              [ -c command | script | - ] [ arguments ]


       Python  is an interpreted, interactive, object-oriented programming language that combines
       remarkable power with very clear syntax.  For an introduction to  programming  in  Python,
       see  the  Python  Tutorial.   The Python Library Reference documents built-in and standard
       types, constants, functions and modules.  Finally, the Python Reference  Manual  describes
       the  syntax  and  semantics  of  the  core  language in (perhaps too) much detail.  (These
       documents may be located via the INTERNET RESOURCES below; they may be installed  on  your
       system as well.)

       Python's  basic  power can be extended with your own modules written in C or C++.  On most
       systems such modules may be dynamically loaded.  Python is also adaptable as an  extension
       language for existing applications.  See the internal documentation for hints.

       Documentation for installed Python modules and packages can be viewed by running the pydoc


       -B     Don't write .pyc files on import. See also PYTHONDONTWRITEBYTECODE.

       -b     Issue warnings about  str(bytes_instance),  str(bytearray_instance)  and  comparing
              bytes/bytearray with str. (-bb: issue errors)

       -c command
              Specify the command to execute (see next section).  This terminates the option list
              (following options are passed as arguments to the command).

       --check-hash-based-pycs mode
              Configure how Python evaluates the up-to-dateness of hash-based .pyc files.

       -d     Turn on  parser  debugging  output  (for  expert  only,  depending  on  compilation

       -E     Ignore  environment  variables  like  PYTHONPATH  and  PYTHONHOME  that  modify the
              behavior of the interpreter.

       -h ,  -? ,  --help
              Prints the usage for the interpreter executable and exits.

       -i     When a script is passed  as  first  argument  or  the  -c  option  is  used,  enter
              interactive  mode  after executing the script or the command.  It does not read the
              $PYTHONSTARTUP file.  This can be useful to inspect global  variables  or  a  stack
              trace when a script raises an exception.

       -I     Run Python in isolated mode. This also implies -E and -s. In isolated mode sys.path
              contains neither the script's directory nor the user's site-packages directory. All
              PYTHON*  environment  variables  are  ignored,  too.   Further  restrictions may be
              imposed to prevent the user from injecting malicious code.

       -m module-name
              Searches sys.path for the named module and runs the corresponding  .py  file  as  a

       -O     Remove  assert  statements  and  any  code  conditional  on the value of __debug__;
              augment the filename for compiled (bytecode) files by adding .opt-1 before the .pyc

       -OO    Do  -O  and  also  discard  docstrings; change the filename for compiled (bytecode)
              files by adding .opt-2 before the .pyc extension.

       -q     Do not print the version and copyright messages. These messages are also suppressed
              in non-interactive mode.

       -s     Don't add user site directory to sys.path.

       -S     Disable  the  import  of  the  module  site and the site-dependent manipulations of
              sys.path that it entails.  Also disable these manipulations if site  is  explicitly
              imported later.

       -u     Force the stdout and stderr streams to be unbuffered.  This option has no effect on
              the stdin stream.

       -v     Print a message each time a module is initialized, showing the place  (filename  or
              built-in  module)  from  which it is loaded.  When given twice, print a message for
              each file that  is  checked  for  when  searching  for  a  module.   Also  provides
              information on module cleanup at exit.

       -V ,  --version
              Prints  the  Python  version number of the executable and exits.  When given twice,
              print more information about the build.

       -W argument
              Warning control.  Python sometimes prints warning message to sys.stderr.  A typical
              warning  message has the following form: file:line: category: message.  By default,
              each warning is printed once for each source line where  it  occurs.   This  option
              controls  how often warnings are printed.  Multiple -W options may be given; when a
              warning matches more than one option, the action for the last  matching  option  is
              performed.   Invalid  -W  options  are  ignored (a warning message is printed about
              invalid options when the first warning is issued).  Warnings can also be controlled
              from within a Python program using the warnings module.

              The  simplest  form of argument is one of the following action strings (or a unique
              abbreviation): ignore to ignore all warnings; default  to  explicitly  request  the
              default  behavior  (printing  each  warning  once  per source line); all to print a
              warning each time it occurs (this may  generate  many  messages  if  a  warning  is
              triggered  repeatedly  for  the same source line, such as inside a loop); module to
              print each warning only the first time it occurs in each module; once to print each
              warning  only  the  first  time  it  occurs  in  the  program; or error to raise an
              exception instead of printing a warning message.

              The full form of argument is action:message:category:module:line.  Here, action  is
              as  explained  above  but only applies to messages that match the remaining fields.
              Empty fields match all values; trailing empty fields may be omitted.   The  message
              field  matches  the  start  of  the  warning  message  printed; this match is case-
              insensitive.  The category field matches the warning  category.   This  must  be  a
              class  name; the match test whether the actual warning category of the message is a
              subclass of the specified warning category.  The full class  name  must  be  given.
              The  module  field  matches  the (fully-qualified) module name; this match is case-
              sensitive.  The line field matches the line number, where  zero  matches  all  line
              numbers and is thus equivalent to an omitted line number.

       -X option
              Set implementation specific option.

       -x     Skip  the first line of the source.  This is intended for a DOS specific hack only.
              Warning: the line numbers in error messages will be off by one!


       The interpreter interface resembles that of the UNIX  shell:  when  called  with  standard
       input connected to a tty device, it prompts for commands and executes them until an EOF is
       read; 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 -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!  In non-interactive
       mode, the entire input is parsed before it is executed.

       If available, the script name and additional arguments thereafter are passed to the script
       in  the Python variable sys.argv, which is a list of strings (you must first import sys to
       be able to access it).  If no script name is given, sys.argv[0] is an empty string; if  -c
       is  used,  sys.argv[0]  contains  the  string  '-c'.  Note that options interpreted by the
       Python interpreter itself are not placed in sys.argv.

       In interactive mode, the primary prompt is `>>>'; the second prompt (which appears when  a
       command is not complete) is `...'.  The prompts can be changed by assignment to sys.ps1 or
       sys.ps2.  The interpreter quits when it reads an EOF  at  a  prompt.   When  an  unhandled
       exception  occurs,  a stack trace is printed and control returns to the primary prompt; in
       non-interactive mode, the interpreter exits after printing the stack trace.  The interrupt
       signal  raises  the KeyboardInterrupt exception; other UNIX signals are not caught (except
       that SIGPIPE is sometimes ignored, in favor of the IOError exception).  Error messages are
       written to stderr.


       These are subject to difference depending on local installation conventions; ${prefix} and
       ${exec_prefix} are installation-dependent and should be interpreted as for  GNU  software;
       they may be the same.  On Debian GNU/{Hurd,Linux} the default for both is /usr.

              Recommended location of the interpreter.

              Recommended locations of the directories containing the standard modules.

              Recommended  locations  of  the directories containing the include files needed for
              developing Python extensions and embedding the interpreter.


              Change the location of the standard Python libraries.  By  default,  the  libraries
              are          searched          in         ${prefix}/lib/python<version>         and
              ${exec_prefix}/lib/python<version>,  where   ${prefix}   and   ${exec_prefix}   are
              installation-dependent   directories,   both   defaulting   to   /usr/local.   When
              $PYTHONHOME is set to a single directory, its value  replaces  both  ${prefix}  and
              ${exec_prefix}.   To  specify  different  values  for  these,  set  $PYTHONHOME  to

              Augments the default search path for module files.  The format is the same  as  the
              shell's  $PATH:  one or more directory pathnames separated by colons.  Non-existent
              directories  are  silently  ignored.   The  default  search  path  is  installation
              dependent,  but generally begins with ${prefix}/lib/python<version> (see PYTHONHOME
              above).  The default search path is always appended to $PYTHONPATH.   If  a  script
              argument  is  given, the directory containing the script is inserted in the path in
              front of $PYTHONPATH.  The search path can be  manipulated  from  within  a  Python
              program as the variable sys.path.

              If  this  is  the  name  of  a  readable file, the Python commands in that file are
              executed before the first prompt is displayed in interactive  mode.   The  file  is
              executed  in  the  same  name space where interactive commands are executed so that
              objects defined or imported  in  it  can  be  used  without  qualification  in  the
              interactive  session.   You can also change the prompts sys.ps1 and sys.ps2 in this

              If this is set to a non-empty string it is equivalent to specifying the -O  option.
              If set to an integer, it is equivalent to specifying -O multiple times.

              If  this is set to a non-empty string it is equivalent to specifying the -d option.
              If set to an integer, it is equivalent to specifying -d multiple times.

              If this is set to a non-empty string it is equivalent to specifying the  -B  option
              (don't try to write .pyc files).

              If this is set to a non-empty string it is equivalent to specifying the -i option.

              If  this  is set before running the interpreter, it overrides the encoding used for
              stdin/stdout/stderr, in the syntax encodingname:errorhandler The errorhandler  part
              is optional and has the same meaning as in str.encode. For stderr, the errorhandler
               part is ignored; the handler will always be ┬┤backslashreplace┬┤.

              If  this  is set to a non-empty string it is equivalent to specifying the -s option
              (Don't add the user site directory to sys.path).

              If this is set to a non-empty string it is equivalent to specifying the -u option.

              If this is set to a non-empty string it is equivalent to specifying the -v  option.
              If set to an integer, it is equivalent to specifying -v multiple times.

              If  this  is  set to a comma-separated string it is equivalent to specifying the -W
              option for each separate value.

              If this variable is set to "random", a random value is used to seed the  hashes  of
              str, bytes and datetime objects.

              If  PYTHONHASHSEED  is  set  to  an  integer  value, it is used as a fixed seed for
              generating the hash() of the types covered by the hash randomization.  Its  purpose
              is  to  allow repeatable hashing, such as for selftests for the interpreter itself,
              or to allow a cluster of python processes to share hash values.

              The integer must be a decimal number in the range [0,4294967295].   Specifying  the
              value 0 will disable hash randomization.

              Set  the  Python memory allocators and/or install debug hooks. The available memory
              allocators  are  malloc  and  pymalloc.   The  available  debug  hooks  are  debug,
              malloc_debug, and pymalloc_debug.

              When  Python is compiled in debug mode, the default is pymalloc_debug and the debug
              hooks are automatically used. Otherwise, the default is pymalloc.

              If set to a non-empty string, Python will print statistics of the  pymalloc  memory
              allocator every time a new pymalloc object arena is created, and on shutdown.

              This variable is ignored if the $PYTHONMALLOC environment variable is used to force
              the malloc(3) allocator of the C  library,  or  if  Python  is  configured  without
              pymalloc support.

              If this environment variable is set to a non-empty string, enable the debug mode of
              the asyncio module.

              If this environment variable is set to a non-empty  string,  start  tracing  Python
              memory allocations using the tracemalloc module.

              The  value of the variable is the maximum number of frames stored in a traceback of
              a trace. For example, PYTHONTRACEMALLOC=1 stores only the most recent frame.

              If this environment variable is set to a non-empty string, faulthandler.enable() is
              called  at  startup:  install  a  handler  for SIGSEGV, SIGFPE, SIGABRT, SIGBUS and
              SIGILL signals to dump the Python traceback.

              This is equivalent to the -X faulthandler option.

              If this environment variable is set, sys.argv[0] will be set to its  value  instead
              of the value got through the C runtime. Only works on Mac OS X.

              Defines  the  user  base  directory,  which is used to compute the path of the user
              site-packages directory  and  Distutils  installation  paths  for  python
              install --user.

              If  this  environment  variable  is set to a non-empty string, Python will show how
              long each import takes. This is exactly equivalent to setting -X importtime on  the
              command line.

              If  this environment variable is set to 0, it disables the default debugger. It can
              be set to the callable of your debugger of choice.

   Debug-mode variables
       Setting these variables only has an effect in a debug build of Python, that is, if  Python
       was configured with the --with-pydebug build option.

              If this environment variable is set, Python will print threading debug info.

              If  this environment variable is set, Python will dump objects and reference counts
              still alive after shutting down the interpreter.


       The Python Software Foundation:


       Main website:
       Developer resources:
       Module repository:
       Newsgroups:  comp.lang.python, comp.lang.python.announce


       Python is distributed under an Open Source license.  See the file "LICENSE" in the  Python
       source  distribution  for  information  on  terms & conditions for accessing and otherwise
       using Python and for a DISCLAIMER OF ALL WARRANTIES.