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       python  -  an  interpreted,  interactive,  object-oriented  programming


       python [ -B ] [ -d ] [ -E ] [ -h ] [ -i ] [ -m module-name ]
              [ -O ] [ -O0 ] [ -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 you are referred  to  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

       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.

       -O0    Discard docstrings in addition to the -O optimizations.

       -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.
       On Debian GNU/{Hurd,Linux} the default for both is /usr.

              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
              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 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  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.


       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

             $Date: 2010-01-31 11:09:16 -0500 (Sun, 31 Jan 2010) $