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PYTHON(1)							     PYTHON(1)

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

       python [	-d ] [ -E ] [ -h ] [ -i	] [ -O ]
	      [	-Q argument ] [	-S ] [ -t ] [ -u ] [ -U	]
	      [	-v ] [ -V ] [ -W argument ] [ -x ]
	      [	-c command | script | -	] [ arguments ]

       Python is an interpreted, interactive, object-oriented programming lan-
       guage  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 (per-
       haps too) much detail.  (These documents	may be located via the	INTER-
       NET 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 applica-
       tions.  See the internal	documentation for hints.

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

       -c command
	      Specify  the command to execute (see next	section).  This	termi-
	      nates 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     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.

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

       -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     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.

       -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     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  mod-

	      The  simplest  form  of  argument	is one of the following	action
	      strings (or a unique abbreviation): ignore to ignore  all	 warn-
	      ings; default to explicitly request the default behavior (print-
	      ing each warning once per	source line); all to print  a  warning
	      each  time it occurs (this may generate many messages if a warn-
	      ing is triggered repeatedly for the same source  line,  such  as
	      inside a loop); module to	print each warning only	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:mod-
	      ule: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 warn-
	      ing 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  num-
	      ber,  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!

       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	multi-
       ple statements separated	by newlines.  Leading whitespace  is  signifi-
       cant  in	 Python	statements!  In	non-interactive	mode, the entire input
       is parsed befored 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 conven-
       tions;  ${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<ver-
	      sion>  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	${pre-

	      Augments the default search path for module files.   The	format
	      is  the  same  as	the shell's $PATH: one or more directory path-
	      names  separated	by  colons.   Non-existant   directories   are
	      silently	ignored.   The	default	 search	 path  is installation
	      dependent, but generally begins  with  ${prefix}/lib/python<ver-
	      sion> (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	speci-
	      fying  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	speci-
	      fying  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	speci-
	      fying the	-i option.

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

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

       Guido van Rossum


       And a cast of thousands.

       Main website:
       Community 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  DIS-

			 $Date:	2002/05/09 14:34:47 $		     PYTHON(1)


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