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Diffstat (limited to 'Doc/library/shutil.rst')
| -rw-r--r-- | Doc/library/shutil.rst | 297 |
1 files changed, 240 insertions, 57 deletions
diff --git a/Doc/library/shutil.rst b/Doc/library/shutil.rst index 18f6485..e962112 100644 --- a/Doc/library/shutil.rst +++ b/Doc/library/shutil.rst @@ -47,45 +47,129 @@ Directory and files operations be copied. -.. function:: copyfile(src, dst) +.. function:: copyfile(src, dst, *, follow_symlinks=True) Copy the contents (no metadata) of the file named *src* to a file named - *dst*. *dst* must be the complete target file name; look at - :func:`shutil.copy` for a copy that accepts a target directory path. If - *src* and *dst* are the same files, :exc:`Error` is raised. - The destination location must be writable; otherwise, an :exc:`IOError` exception - will be raised. If *dst* already exists, it will be replaced. Special files - such as character or block devices and pipes cannot be copied with this - function. *src* and *dst* are path names given as strings. + *dst* and return *dst*. *src* and *dst* are path names given as strings. + *dst* must be the complete target file name; look at :func:`shutil.copy` + for a copy that accepts a target directory path. If *src* and *dst* + specify the same file, :exc:`Error` is raised. + The destination location must be writable; otherwise, an :exc:`OSError` + exception will be raised. If *dst* already exists, it will be replaced. + Special files such as character or block devices and pipes cannot be + copied with this function. -.. function:: copymode(src, dst) + If *follow_symlinks* is false and *src* is a symbolic link, + a new symbolic link will be created instead of copying the + file *src* points to. + + .. versionchanged:: 3.3 + :exc:`IOError` used to be raised instead of :exc:`OSError`. + Added *follow_symlinks* argument. + Now returns *dst*. + +.. function:: copymode(src, dst, *, follow_symlinks=True) Copy the permission bits from *src* to *dst*. The file contents, owner, and group are unaffected. *src* and *dst* are path names given as strings. + If *follow_symlinks* is false, and both *src* and *dst* are symbolic links, + :func:`copymode` will attempt to modify the mode of *dst* itself (rather + than the file it points to). This functionality is not available on every + platform; please see :func:`copystat` for more information. If + :func:`copymode` cannot modify symbolic links on the local platform, and it + is asked to do so, it will do nothing and return. + + .. versionchanged:: 3.3 + Added *follow_symlinks* argument. + +.. function:: copystat(src, dst, *, follow_symlinks=True) + + Copy the permission bits, last access time, last modification time, and + flags from *src* to *dst*. On Linux, :func:`copystat` also copies the + "extended attributes" where possible. The file contents, owner, and + group are unaffected. *src* and *dst* are path names given as strings. + + If *follow_symlinks* is false, and *src* and *dst* both + refer to symbolic links, :func:`copystat` will operate on + the symbolic links themselves rather than the files the + symbolic links refer to--reading the information from the + *src* symbolic link, and writing the information to the + *dst* symbolic link. + + .. note:: + + Not all platforms provide the ability to examine and + modify symbolic links. Python itself can tell you what + functionality is locally available. + * If ``os.chmod in os.supports_follow_symlinks`` is + ``True``, :func:`copystat` can modify the permission + bits of a symbolic link. -.. function:: copystat(src, dst) + * If ``os.utime in os.supports_follow_symlinks`` is + ``True``, :func:`copystat` can modify the last access + and modification times of a symbolic link. - Copy the permission bits, last access time, last modification time, and flags - from *src* to *dst*. The file contents, owner, and group are unaffected. *src* - and *dst* are path names given as strings. + * If ``os.chflags in os.supports_follow_symlinks`` is + ``True``, :func:`copystat` can modify the flags of + a symbolic link. (``os.chflags`` is not available on + all platforms.) + On platforms where some or all of this functionality + is unavailable, when asked to modify a symbolic link, + :func:`copystat` will copy everything it can. + :func:`copystat` never returns failure. -.. function:: copy(src, dst) + Please see :data:`os.supports_follow_symlinks` + for more information. - Copy the file *src* to the file or directory *dst*. If *dst* is a directory, a - file with the same basename as *src* is created (or overwritten) in the - directory specified. Permission bits are copied. *src* and *dst* are path - names given as strings. + .. versionchanged:: 3.3 + Added *follow_symlinks* argument and support for Linux extended attributes. +.. function:: copy(src, dst, *, follow_symlinks=True) -.. function:: copy2(src, dst) + Copies the file *src* to the file or directory *dst*. *src* and *dst* + should be strings. If *dst* specifies a directory, the file will be + copied into *dst* using the base filename from *src*. Returns the + path to the newly created file. - Similar to :func:`shutil.copy`, but metadata is copied as well -- in fact, - this is just :func:`shutil.copy` followed by :func:`copystat`. This is - similar to the Unix command :program:`cp -p`. + If *follow_symlinks* is false, and *src* is a symbolic link, + *dst* will be created as a symbolic link. If *follow_symlinks* + is true and *src* is a symbolic link, *dst* will be a copy of + the file *src* refers to. + :func:`copy` copies the file data and the file's permission + mode (see :func:`os.chmod`). Other metadata, like the + file's creation and modification times, is not preserved. + To preserve all file metadata from the original, use + :func:`~shutil.copy2` instead. + + .. versionchanged:: 3.3 + Added *follow_symlinks* argument. + Now returns path to the newly created file. + +.. function:: copy2(src, dst, *, follow_symlinks=True) + + Identical to :func:`~shutil.copy` except that :func:`copy2` + also attempts to preserve all file metadata. + + When *follow_symlinks* is false, and *src* is a symbolic + link, :func:`copy2` attempts to copy all metadata from the + *src* symbolic link to the newly-created *dst* symbolic link. + However, this functionality is not available on all platforms. + On platforms where some or all of this functionality is + unavailable, :func:`copy2` will preserve all the metadata + it can; :func:`copy2` never returns failure. + + :func:`copy2` uses :func:`copystat` to copy the file metadata. + Please see :func:`copystat` for more information + about platform support for modifying symbolic link metadata. + + .. versionchanged:: 3.3 + Added *follow_symlinks* argument, try to copy extended + file system attributes too (currently Linux only). + Now returns path to the newly created file. .. function:: ignore_patterns(\*patterns) @@ -96,16 +180,17 @@ Directory and files operations .. function:: copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2, ignore_dangling_symlinks=False) - Recursively copy an entire directory tree rooted at *src*. The destination + Recursively copy an entire directory tree rooted at *src*, returning the + destination directory. The destination directory, named by *dst*, must not already exist; it will be created as well as missing parent directories. Permissions and times of directories are copied with :func:`copystat`, individual files are copied using :func:`shutil.copy2`. If *symlinks* is true, symbolic links in the source tree are represented as - symbolic links in the new tree, but the metadata of the original links is NOT - copied; if false or omitted, the contents and metadata of the linked files - are copied to the new tree. + symbolic links in the new tree and the metadata of the original links will + be copied as far as the platform allows; if false or omitted, the contents + and metadata of the linked files are copied to the new tree. When *symlinks* is false, if the file pointed by the symlink doesn't exist, a exception will be added in the list of errors raised in @@ -129,13 +214,15 @@ Directory and files operations If *copy_function* is given, it must be a callable that will be used to copy each file. It will be called with the source path and the destination path as arguments. By default, :func:`shutil.copy2` is used, but any function - that supports the same signature (like :func:`copy`) can be used. + that supports the same signature (like :func:`shutil.copy`) can be used. + + .. versionchanged:: 3.3 + Copy metadata when *symlinks* is false. + Now returns *dst*. .. versionchanged:: 3.2 Added the *copy_function* argument to be able to provide a custom copy function. - - .. versionchanged:: 3.2 Added the *ignore_dangling_symlinks* argument to silent dangling symlinks errors when *symlinks* is false. @@ -150,19 +237,42 @@ Directory and files operations handled by calling a handler specified by *onerror* or, if that is omitted, they raise an exception. + .. note:: + + On platforms that support the necessary fd-based functions a symlink + attack resistant version of :func:`rmtree` is used by default. On other + platforms, the :func:`rmtree` implementation is susceptible to a symlink + attack: given proper timing and circumstances, attackers can manipulate + symlinks on the filesystem to delete files they wouldn't be able to access + otherwise. Applications can use the :data:`rmtree.avoids_symlink_attacks` + function attribute to determine which case applies. + If *onerror* is provided, it must be a callable that accepts three - parameters: *function*, *path*, and *excinfo*. The first parameter, - *function*, is the function which raised the exception; it will be - :func:`os.path.islink`, :func:`os.listdir`, :func:`os.remove` or - :func:`os.rmdir`. The second parameter, *path*, will be the path name passed - to *function*. The third parameter, *excinfo*, will be the exception - information return by :func:`sys.exc_info`. Exceptions raised by *onerror* - will not be caught. + parameters: *function*, *path*, and *excinfo*. + + The first parameter, *function*, is the function which raised the exception; + it depends on the platform and implementation. The second parameter, + *path*, will be the path name passed to *function*. The third parameter, + *excinfo*, will be the exception information returned by + :func:`sys.exc_info`. Exceptions raised by *onerror* will not be caught. + + .. versionchanged:: 3.3 + Added a symlink attack resistant version that is used automatically + if platform supports fd-based functions. + + .. attribute:: rmtree.avoids_symlink_attacks + + Indicates whether the current platform and implementation provides a + symlink attack resistant version of :func:`rmtree`. Currently this is + only true for platforms supporting fd-based directory access functions. + + .. versionadded:: 3.3 .. function:: move(src, dst) - Recursively move a file or directory (*src*) to another location (*dst*). + Recursively move a file or directory (*src*) to another location (*dst*) + and return the destination. If the destination is a directory or a symlink to a directory, then *src* is moved inside that directory. @@ -173,7 +283,61 @@ Directory and files operations If the destination is on the current filesystem, then :func:`os.rename` is used. Otherwise, *src* is copied (using :func:`shutil.copy2`) to *dst* and - then removed. + then removed. In case of symlinks, a new symlink pointing to the target of + *src* will be created in or as *dst* and *src* will be removed. + + .. versionchanged:: 3.3 + Added explicit symlink handling for foreign filesystems, thus adapting + it to the behavior of GNU's :program:`mv`. + Now returns *dst*. + +.. function:: disk_usage(path) + + Return disk usage statistics about the given path as a :term:`named tuple` + with the attributes *total*, *used* and *free*, which are the amount of + total, used and free space, in bytes. + + .. versionadded:: 3.3 + + Availability: Unix, Windows. + +.. function:: chown(path, user=None, group=None) + + Change owner *user* and/or *group* of the given *path*. + + *user* can be a system user name or a uid; the same applies to *group*. At + least one argument is required. + + See also :func:`os.chown`, the underlying function. + + Availability: Unix. + + .. versionadded:: 3.3 + + +.. function:: which(cmd, mode=os.F_OK | os.X_OK, path=None) + + Return the path to an executable which would be run if the given *cmd* was + called. If no *cmd* would be called, return ``None``. + + *mode* is a permission mask passed a to :func:`os.access`, by default + determining if the file exists and executable. + + When no *path* is specified, the results of :func:`os.environ` are used, + returning either the "PATH" value or a fallback of :attr:`os.defpath`. + + On Windows, the current directory is always prepended to the *path* whether + or not you use the default or provide your own, which is the behavior the + command shell uses when finding executables. Additionaly, when finding the + *cmd* in the *path*, the ``PATHEXT`` environment variable is checked. For + example, if you call ``shutil.which("python")``, :func:`which` will search + ``PATHEXT`` to know that it should look for ``python.exe`` within the *path* + directories. For example, on Windows:: + + >>> shutil.which("python") + 'c:\\python33\\python.exe' + + .. versionadded:: 3.3 .. exception:: Error @@ -186,7 +350,7 @@ Directory and files operations .. _shutil-copytree-example: copytree example -:::::::::::::::: +~~~~~~~~~~~~~~~~ This example is the implementation of the :func:`copytree` function, described above, with the docstring omitted. It demonstrates many of the other functions @@ -208,7 +372,7 @@ provided by this module. :: else: copy2(srcname, dstname) # XXX What about devices, sockets etc.? - except (IOError, os.error) as why: + except OSError as why: errors.append((srcname, dstname, str(why))) # catch the Error from the recursive copytree so that we can # continue with other files @@ -250,6 +414,8 @@ Another example that uses the *ignore* argument to add a logging call:: Archiving operations -------------------- +.. versionadded:: 3.2 + High-level utilities to create and read compressed and archived files are also provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. @@ -277,8 +443,6 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. *logger* must be an object compatible with :pep:`282`, usually an instance of :class:`logging.Logger`. - .. versionadded:: 3.2 - .. function:: get_archive_formats() @@ -295,8 +459,6 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. You can register new formats or provide your own archiver for any existing formats, by using :func:`register_archive_format`. - .. versionadded:: 3.2 - .. function:: register_archive_format(name, function, [extra_args, [description]]) @@ -309,15 +471,11 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. *description* is used by :func:`get_archive_formats` which returns the list of archivers. Defaults to an empty list. - .. versionadded:: 3.2 - .. function:: unregister_archive_format(name) Remove the archive format *name* from the list of supported formats. - .. versionadded:: 3.2 - .. function:: unpack_archive(filename[, extract_dir[, format]]) @@ -332,8 +490,6 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. and see if an unpacker was registered for that extension. In case none is found, a :exc:`ValueError` is raised. - .. versionadded:: 3.2 - .. function:: register_unpack_format(name, extensions, function[, extra_args[, description]]) @@ -351,15 +507,11 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. *description* can be provided to describe the format, and will be returned by the :func:`get_unpack_formats` function. - .. versionadded:: 3.2 - .. function:: unregister_unpack_format(name) Unregister an unpack format. *name* is the name of the format. - .. versionadded:: 3.2 - .. function:: get_unpack_formats() @@ -377,13 +529,11 @@ provided. They rely on the :mod:`zipfile` and :mod:`tarfile` modules. You can register new formats or provide your own unpacker for any existing formats, by using :func:`register_unpack_format`. - .. versionadded:: 3.2 - .. _shutil-archiving-example: Archiving example -::::::::::::::::: +~~~~~~~~~~~~~~~~~ In this example, we create a gzip'ed tar-file archive containing all files found in the :file:`.ssh` directory of the user:: @@ -406,3 +556,36 @@ The resulting archive contains:: -rw------- tarek/staff 1675 2008-06-09 13:26:54 ./id_rsa -rw-r--r-- tarek/staff 397 2008-06-09 13:26:54 ./id_rsa.pub -rw-r--r-- tarek/staff 37192 2010-02-06 18:23:10 ./known_hosts + + +Querying the size of the output terminal +---------------------------------------- + +.. versionadded:: 3.3 + +.. function:: get_terminal_size(fallback=(columns, lines)) + + Get the size of the terminal window. + + For each of the two dimensions, the environment variable, ``COLUMNS`` + and ``LINES`` respectively, is checked. If the variable is defined and + the value is a positive integer, it is used. + + When ``COLUMNS`` or ``LINES`` is not defined, which is the common case, + the terminal connected to :data:`sys.__stdout__` is queried + by invoking :func:`os.get_terminal_size`. + + If the terminal size cannot be successfully queried, either because + the system doesn't support querying, or because we are not + connected to a terminal, the value given in ``fallback`` parameter + is used. ``fallback`` defaults to ``(80, 24)`` which is the default + size used by many terminal emulators. + + The value returned is a named tuple of type :class:`os.terminal_size`. + + See also: The Single UNIX Specification, Version 2, + `Other Environment Variables`_. + +.. _`Other Environment Variables`: + http://pubs.opengroup.org/onlinepubs/7908799/xbd/envvar.html#tag_002_003 + |