Command Section
PYTHON(1)               FreeBSD General Commands Manual              PYTHON(1)

       python - an interpreted, interactive, object-oriented programming

       python [ -B ] [ -d ] [ -E ] [ -h ] [ -i ] [ -m module-name ]
              [ -O ] [ -OO ] [ -R ] [ -Q argument ] [ -s ] [ -S ] [ -t ] [ -u
              [ -v ] [ -V ] [ -W argument ] [ -x ] [ -3 ] [ -?  ]
              [ -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 program.

       -B     Don't write .py[co] files on import. See also

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

       -d     Turn on parser debugging output (for wizards only, depending on
              compilation options).

       -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.

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

       -O     Turn on basic optimizations.  This changes the filename
              extension for compiled (bytecode) files from .pyc to .pyo.
              Given twice, causes docstrings to be discarded.

       -OO    Discard docstrings in addition to the -O optimizations.

       -R     Turn on "hash randomization", so that the hash() values of str,
              bytes and datetime objects are "salted" with an unpredictable
              pseudo-random value.  Although they remain constant within an
              individual Python process, they are not predictable between
              repeated invocations of Python.

              This is intended to provide protection against a denial of
              service caused by carefully-chosen inputs that exploit the worst
              case performance of a dict construction, O(n^2) complexity.  See
     for details.

       -Q argument
              Division control; see PEP 238.  The argument must be one of
              "old" (the default, int/int and long/long return an int or
              long), "new" (new division semantics, i.e. int/int and long/long
              returns a float), "warn" (old division semantics with a warning
              for int/int and long/long), or "warnall" (old division semantics
              with a warning for all use of the division operator).  For a use
              of "warnall", see the Tools/scripts/ script.

       -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.

       -t     Issue a warning when a source file mixes tabs and spaces for
              indentation in a way that makes it depend on the worth of a tab
              expressed in spaces.  Issue an error when the option is given

       -u     Force stdin, stdout and stderr to be totally unbuffered.  On
              systems where it matters, also put stdin, stdout and stderr in
              binary mode.  Note that there is internal buffering in
              xreadlines(), readlines() and file-object iterators ("for line
              in sys.stdin") which is not influenced by this option.  To work
              around this, you will want to use "sys.stdin.readline()" inside
              a "while 1:" loop.

       -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.

       -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

              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     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!

       -3     Warn about Python 3.x incompatibilities that 2to3 cannot
              trivially fix.

       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.
       The default for both is /usr/local.

              Recommended location of the interpreter.

              Recommended locations of the directories containing the standard

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

              User-specific initialization file loaded by the user module; not
              used by default or by most applications.

              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

              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 file.

              Set this to a non-empty string to cause the time module to
              require dates specified as strings to include 4-digit years,
              otherwise 2-digit years are converted based on rules described
              in the time module documentation.

              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 .py[co] 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
               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

              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", 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.

              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 lead to the same
              hash values as when hash randomization is disabled.

       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

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