mirror of
https://github.com/python/cpython.git
synced 2024-12-15 21:04:00 +08:00
436 lines
13 KiB
Groff
436 lines
13 KiB
Groff
.TH PYTHON "1" "$Date$"
|
|
|
|
.\" To view this file while editing, run it through groff:
|
|
.\" groff -Tascii -man python.man | less
|
|
|
|
.SH NAME
|
|
python \- an interpreted, interactive, object-oriented programming language
|
|
.SH SYNOPSIS
|
|
.B python
|
|
[
|
|
.B \-B
|
|
]
|
|
[
|
|
.B \-d
|
|
]
|
|
[
|
|
.B \-E
|
|
]
|
|
[
|
|
.B \-h
|
|
]
|
|
[
|
|
.B \-i
|
|
]
|
|
[
|
|
.B \-m
|
|
.I module-name
|
|
]
|
|
[
|
|
.B \-q
|
|
]
|
|
.br
|
|
[
|
|
.B \-O
|
|
]
|
|
[
|
|
.B \-OO
|
|
]
|
|
[
|
|
.B \-s
|
|
]
|
|
[
|
|
.B \-S
|
|
]
|
|
[
|
|
.B \-u
|
|
]
|
|
.br
|
|
[
|
|
.B \-v
|
|
]
|
|
[
|
|
.B \-V
|
|
]
|
|
[
|
|
.B \-W
|
|
.I argument
|
|
]
|
|
[
|
|
.B \-x
|
|
]
|
|
[
|
|
.B \-?
|
|
]
|
|
.br
|
|
[
|
|
.B \-c
|
|
.I command
|
|
|
|
|
.I script
|
|
|
|
|
\-
|
|
]
|
|
[
|
|
.I arguments
|
|
]
|
|
.SH DESCRIPTION
|
|
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
|
|
.B "INTERNET RESOURCES"
|
|
below; they may be installed on your system as well.)
|
|
.PP
|
|
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.
|
|
.PP
|
|
Documentation for installed Python modules and packages can be
|
|
viewed by running the
|
|
.B pydoc
|
|
program.
|
|
.SH COMMAND LINE OPTIONS
|
|
.TP
|
|
.B \-B
|
|
Don't write
|
|
.I .py[co]
|
|
files on import. See also PYTHONDONTWRITEBYTECODE.
|
|
.TP
|
|
.BI "\-c " command
|
|
Specify the command to execute (see next section).
|
|
This terminates the option list (following options are passed as
|
|
arguments to the command).
|
|
.TP
|
|
.B \-d
|
|
Turn on parser debugging output (for wizards only, depending on
|
|
compilation options).
|
|
.TP
|
|
.B \-E
|
|
Ignore environment variables like PYTHONPATH and PYTHONHOME that modify
|
|
the behavior of the interpreter.
|
|
.TP
|
|
.B \-h ", " \-? ", "\-\-help
|
|
Prints the usage for the interpreter executable and exits.
|
|
.TP
|
|
.B \-i
|
|
When a script is passed as first argument or the \fB\-c\fP 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.
|
|
.TP
|
|
.BI "\-m " module-name
|
|
Searches
|
|
.I sys.path
|
|
for the named module and runs the corresponding
|
|
.I .py
|
|
file as a script.
|
|
.TP
|
|
.B \-O
|
|
Turn on basic optimizations. This changes the filename extension for
|
|
compiled (bytecode) files from
|
|
.I .pyc
|
|
to \fI.pyo\fP. Given twice, causes docstrings to be discarded.
|
|
.TP
|
|
.B \-OO
|
|
Discard docstrings in addition to the \fB-O\fP optimizations.
|
|
.TP
|
|
.B \-q
|
|
Do not print the version and copyright messages. These messages are
|
|
also suppressed in non-interactive mode.
|
|
.TP
|
|
.B \-s
|
|
Don't add user site directory to sys.path.
|
|
.TP
|
|
.B \-S
|
|
Disable the import of the module
|
|
.I site
|
|
and the site-dependent manipulations of
|
|
.I sys.path
|
|
that it entails. Also disable these manipulations if
|
|
.I site
|
|
is explicitly imported later.
|
|
.TP
|
|
.B \-u
|
|
Force the binary I/O layers of stdin, stdout and stderr to be unbuffered.
|
|
The text I/O layer will still be line-buffered.
|
|
.\" Note that there is internal buffering in 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.
|
|
.TP
|
|
.B \-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.
|
|
.TP
|
|
.B \-V ", " \-\-version
|
|
Prints the Python version number of the executable and exits.
|
|
.TP
|
|
.BI "\-W " argument
|
|
Warning control. Python sometimes prints warning message to
|
|
.IR sys.stderr .
|
|
A typical warning message has the following form:
|
|
.IB 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
|
|
.B \-W
|
|
options may be given; when a warning matches more than one
|
|
option, the action for the last matching option is performed.
|
|
Invalid
|
|
.B \-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
|
|
.I warnings
|
|
module.
|
|
|
|
The simplest form of
|
|
.I argument
|
|
is one of the following
|
|
.I action
|
|
strings (or a unique abbreviation):
|
|
.B ignore
|
|
to ignore all warnings;
|
|
.B default
|
|
to explicitly request the default behavior (printing each warning once
|
|
per source line);
|
|
.B 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);
|
|
.B module
|
|
to print each warning only the first time it occurs in each
|
|
module;
|
|
.B once
|
|
to print each warning only the first time it occurs in the program; or
|
|
.B error
|
|
to raise an exception instead of printing a warning message.
|
|
|
|
The full form of
|
|
.I argument
|
|
is
|
|
.IB action : message : category : module : line.
|
|
Here,
|
|
.I 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
|
|
.I message
|
|
field matches the start of the warning message printed; this match is
|
|
case-insensitive. The
|
|
.I 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
|
|
.I module
|
|
field matches the (fully-qualified) module name; this match is
|
|
case-sensitive. The
|
|
.I line
|
|
field matches the line number, where zero matches all line numbers and
|
|
is thus equivalent to an omitted line number.
|
|
.TP
|
|
.B \-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!
|
|
.SH INTERPRETER INTERFACE
|
|
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
|
|
.I script
|
|
from that file;
|
|
when called with
|
|
.B \-c
|
|
.IR command ,
|
|
it executes the Python statement(s) given as
|
|
.IR command .
|
|
Here
|
|
.I 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.
|
|
.PP
|
|
If available, the script name and additional arguments thereafter are
|
|
passed to the script in the Python variable
|
|
.IR sys.argv ,
|
|
which is a list of strings (you must first
|
|
.I import sys
|
|
to be able to access it).
|
|
If no script name is given,
|
|
.I sys.argv[0]
|
|
is an empty string; if
|
|
.B \-c
|
|
is used,
|
|
.I sys.argv[0]
|
|
contains the string
|
|
.I '-c'.
|
|
Note that options interpreted by the Python interpreter itself
|
|
are not placed in
|
|
.IR sys.argv .
|
|
.PP
|
|
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
|
|
.I sys.ps1
|
|
or
|
|
.IR 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
|
|
.I Keyboard\%Interrupt
|
|
exception; other UNIX signals are not caught (except that SIGPIPE is
|
|
sometimes ignored, in favor of the
|
|
.I IOError
|
|
exception). Error messages are written to stderr.
|
|
.SH FILES AND DIRECTORIES
|
|
These are subject to difference depending on local installation
|
|
conventions; ${prefix} and ${exec_prefix} are installation-dependent
|
|
and should be interpreted as for GNU software; they may be the same.
|
|
The default for both is \fI/usr/local\fP.
|
|
.IP \fI${exec_prefix}/bin/python\fP
|
|
Recommended location of the interpreter.
|
|
.PP
|
|
.I ${prefix}/lib/python<version>
|
|
.br
|
|
.I ${exec_prefix}/lib/python<version>
|
|
.RS
|
|
Recommended locations of the directories containing the standard
|
|
modules.
|
|
.RE
|
|
.PP
|
|
.I ${prefix}/include/python<version>
|
|
.br
|
|
.I ${exec_prefix}/include/python<version>
|
|
.RS
|
|
Recommended locations of the directories containing the include files
|
|
needed for developing Python extensions and embedding the
|
|
interpreter.
|
|
.RE
|
|
.SH ENVIRONMENT VARIABLES
|
|
.IP PYTHONHOME
|
|
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
|
|
\fI/usr/local\fP. 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 ${prefix}:${exec_prefix}.
|
|
.IP PYTHONPATH
|
|
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
|
|
.IR sys.path .
|
|
.IP PYTHONSTARTUP
|
|
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
|
|
.I sys.ps1
|
|
and
|
|
.I sys.ps2
|
|
in this file.
|
|
.IP PYTHONY2K
|
|
Set this to a non-empty string to cause the \fItime\fP module to
|
|
require dates specified as strings to include 4-digit years, otherwise
|
|
2-digit years are converted based on rules described in the \fItime\fP
|
|
module documentation.
|
|
.IP PYTHONOPTIMIZE
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-O\fP option. If set to an integer, it is equivalent to
|
|
specifying \fB\-O\fP multiple times.
|
|
.IP PYTHONDEBUG
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-d\fP option. If set to an integer, it is equivalent to
|
|
specifying \fB\-d\fP multiple times.
|
|
.IP PYTHONDONTWRITEBYTECODE
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-B\fP option (don't try to write
|
|
.I .py[co]
|
|
files).
|
|
.IP PYTHONINSPECT
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-i\fP option.
|
|
.IP PYTHONIOENCODING
|
|
If this is set before running the interpreter, it overrides the encoding used
|
|
for stdin/stdout/stderr, in the syntax
|
|
.IB encodingname ":" errorhandler
|
|
The
|
|
.IB errorhandler
|
|
part is optional and has the same meaning as in str.encode. For stderr, the
|
|
.IB errorhandler
|
|
part is ignored; the handler will always be \'backslashreplace\'.
|
|
.IP PYTHONNOUSERSITE
|
|
If this is set to a non-empty string it is equivalent to specifying the
|
|
\fB\-s\fP option (Don't add the user site directory to sys.path).
|
|
.IP PYTHONUNBUFFERED
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-u\fP option.
|
|
.IP PYTHONVERBOSE
|
|
If this is set to a non-empty string it is equivalent to specifying
|
|
the \fB\-v\fP option. If set to an integer, it is equivalent to
|
|
specifying \fB\-v\fP multiple times.
|
|
.IP PYTHONWARNINGS
|
|
If this is set to a comma-separated string it is equivalent to
|
|
specifying the \fB\-W\fP option for each separate value.
|
|
.IP PYTHONHASHSEED
|
|
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.
|
|
.SH AUTHOR
|
|
The Python Software Foundation: http://www.python.org/psf
|
|
.SH INTERNET RESOURCES
|
|
Main website: http://www.python.org/
|
|
.br
|
|
Documentation: http://docs.python.org/py3k/
|
|
.br
|
|
Developer resources: http://docs.python.org/devguide/
|
|
.br
|
|
Downloads: http://python.org/download/
|
|
.br
|
|
Module repository: http://pypi.python.org/
|
|
.br
|
|
Newsgroups: comp.lang.python, comp.lang.python.announce
|
|
.SH LICENSING
|
|
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.
|