Python3 shutil模块

　　平时我们总会用到复制文件的命令，Python中自带了相应模块，那就是shutil模块，下面是shutil模块的分析及用法。

　　1、copyfileobj(fsrc, fdst, length=16*1024)

　　将源文件拷贝到目标文件，每次拷贝16KB。这个方法中，原文件及目标文件并没有进行关闭，所以这是一个基本方法，并不经常使用。

 def copyfileobj(fsrc, fdst, length=16*1024):
     """copy data from file-like object fsrc to file-like object fdst"""
     while 1:
         buf = fsrc.read(length)
         if not buf:
             break
         fdst.write(buf)

source code

　　2、copyfile(src, dst, *, follow_symlinks=True)

　　拷贝源文件到目标文件，如果follow_symlinks项没有设定并且源文件是一个链接，则只拷贝连接，不拷贝指向的文件。

 def copyfile(src, dst, *, follow_symlinks=True):
     """Copy data from src to dst.

     If follow_symlinks is not set and src is a symbolic link, a new
     symlink will be created instead of copying the file it points to.

     """
     if _samefile(src, dst):
         raise SameFileError("{!r} and {!r} are the same file".format(src, dst))

     for fn in [src, dst]:
         try:
             st = os.stat(fn)
         except OSError:
             # File most likely does not exist
             pass
         else:
             # XXX What about other special files? (sockets, devices...)
             if stat.S_ISFIFO(st.st_mode):
                 raise SpecialFileError("`%s` is a named pipe" % fn)

     if not follow_symlinks and os.path.islink(src):
         os.symlink(os.readlink(src), dst)
     else:
         with open(src, 'rb') as fsrc:
             with open(dst, 'wb') as fdst:
                 copyfileobj(fsrc, fdst)
     return dst

source code

　　3、copymode(src, dst, *, follow_symlinks=True)

　　仅拷贝文件权限，如果follow_symlinks项没有设定并且两个文件都是链接，如果lchmod（比如linux系统）不可用，那么这个方法也不可用。

 def copymode(src, dst, *, follow_symlinks=True):
     """Copy mode bits from src to dst.

     If follow_symlinks is not set, symlinks aren't followed if and only
     if both `src` and `dst` are symlinks.  If `lchmod` isn't available
     (e.g. Linux) this method does nothing.

     """
     if not follow_symlinks and os.path.islink(src) and os.path.islink(dst):
         if hasattr(os, 'lchmod'):
             stat_func, chmod_func = os.lstat, os.lchmod
         else:
             return
     elif hasattr(os, 'chmod'):
         stat_func, chmod_func = os.stat, os.chmod
     else:
         return

     st = stat_func(src)
     chmod_func(dst, stat.S_IMODE(st.st_mode))

source code

　　4、copystat(src, dst, *, follow_symlinks=True)

　　拷贝状态信息

 def copystat(src, dst, *, follow_symlinks=True):
     """Copy all stat info (mode bits, atime, mtime, flags) from src to dst.

     If the optional flag `follow_symlinks` is not set, symlinks aren't followed if and
     only if both `src` and `dst` are symlinks.

     """
     def _nop(*args, ns=None, follow_symlinks=None):
         pass

     # follow symlinks (aka don't not follow symlinks)
     follow = follow_symlinks or not (os.path.islink(src) and os.path.islink(dst))
     if follow:
         # use the real function if it exists
         def lookup(name):
             return getattr(os, name, _nop)
     else:
         # use the real function only if it exists
         # *and* it supports follow_symlinks
         def lookup(name):
             fn = getattr(os, name, _nop)
             if fn in os.supports_follow_symlinks:
                 return fn
             return _nop

     st = lookup("stat")(src, follow_symlinks=follow)
     mode = stat.S_IMODE(st.st_mode)
     lookup("utime")(dst, ns=(st.st_atime_ns, st.st_mtime_ns),
         follow_symlinks=follow)
     try:
         lookup("chmod")(dst, mode, follow_symlinks=follow)
     except NotImplementedError:
         # if we got a NotImplementedError, it's because
         #   * follow_symlinks=False,
         #   * lchown() is unavailable, and
         #   * either
         #       * fchownat() is unavailable or
         #       * fchownat() doesn't implement AT_SYMLINK_NOFOLLOW.
         #         (it returned ENOSUP.)
         # therefore we're out of options--we simply cannot chown the
         # symlink.  give up, suppress the error.
         # (which is what shutil always did in this circumstance.)
         pass
     if hasattr(st, 'st_flags'):
         try:
             lookup("chflags")(dst, st.st_flags, follow_symlinks=follow)
         except OSError as why:
             for err in 'EOPNOTSUPP', 'ENOTSUP':
                 if hasattr(errno, err) and why.errno == getattr(errno, err):
                     break
             else:
                 raise
     _copyxattr(src, dst, follow_symlinks=follow)

source code

　　5、copy(src, dst, *, follow_symlinks=True)

　　拷贝文件及权限

 def copy(src, dst, *, follow_symlinks=True):
     """Copy data and mode bits ("cp src dst"). Return the file's destination.

     The destination may be a directory.

     If follow_symlinks is false, symlinks won't be followed. This
     resembles GNU's "cp -P src dst".

     If source and destination are the same file, a SameFileError will be
     raised.

     """
     if os.path.isdir(dst):
         dst = os.path.join(dst, os.path.basename(src))
     copyfile(src, dst, follow_symlinks=follow_symlinks)
     copymode(src, dst, follow_symlinks=follow_symlinks)
     return dst

source code

　　6、copy2(src, dst, *, follow_symlinks=True)

　　拷贝文件和状态信息

 def copy2(src, dst, *, follow_symlinks=True):
     """Copy data and all stat info ("cp -p src dst"). Return the file's
     destination."

     The destination may be a directory.

     If follow_symlinks is false, symlinks won't be followed. This
     resembles GNU's "cp -P src dst".

     """
     if os.path.isdir(dst):
         dst = os.path.join(dst, os.path.basename(src))
     copyfile(src, dst, follow_symlinks=follow_symlinks)
     copystat(src, dst, follow_symlinks=follow_symlinks)
     return dst

source code

　　7、ignore_patterns(*patterns)

　　忽略特定文件。与递归拷贝等进行连用去除不需要操作的文件。

 def ignore_patterns(*patterns):
     """Function that can be used as copytree() ignore parameter.

     Patterns is a sequence of glob-style patterns
     that are used to exclude files"""
     def _ignore_patterns(path, names):
         ignored_names = []
         for pattern in patterns:
             ignored_names.extend(fnmatch.filter(names, pattern))
         return set(ignored_names)
     return _ignore_patterns

source code

　　8、copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2,ignore_dangling_symlinks=False)

　　递归拷贝文件

 def copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2,
              ignore_dangling_symlinks=False):
     """Recursively copy a directory tree.

     The destination directory must not already exist.
     If exception(s) occur, an Error is raised with a list of reasons.

     If the optional symlinks flag is true, symbolic links in the
     source tree result in symbolic links in the destination tree; if
     it is false, the contents of the files pointed to by symbolic
     links are copied. If the file pointed by the symlink doesn't
     exist, an exception will be added in the list of errors raised in
     an Error exception at the end of the copy process.

     You can set the optional ignore_dangling_symlinks flag to true if you
     want to silence this exception. Notice that this has no effect on
     platforms that don't support os.symlink.

     The optional ignore argument is a callable. If given, it
     is called with the `src` parameter, which is the directory
     being visited by copytree(), and `names` which is the list of
     `src` contents, as returned by os.listdir():

         callable(src, names) -> ignored_names

     Since copytree() is called recursively, the callable will be
     called once for each directory that is copied. It returns a
     list of names relative to the `src` directory that should
     not be copied.

     The optional copy_function argument is 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, copy2() is used, but any
     function that supports the same signature (like copy()) can be used.

     """
     names = os.listdir(src)
     if ignore is not None:
         ignored_names = ignore(src, names)
     else:
         ignored_names = set()

     os.makedirs(dst)
     errors = []
     for name in names:
         if name in ignored_names:
             continue
         srcname = os.path.join(src, name)
         dstname = os.path.join(dst, name)
         try:
             if os.path.islink(srcname):
                 linkto = os.readlink(srcname)
                 if symlinks:
                     # We can't just leave it to `copy_function` because legacy
                     # code with a custom `copy_function` may rely on copytree
                     # doing the right thing.
                     os.symlink(linkto, dstname)
                     copystat(srcname, dstname, follow_symlinks=not symlinks)
                 else:
                     # ignore dangling symlink if the flag is on
                     if not os.path.exists(linkto) and ignore_dangling_symlinks:
                         continue
                     # otherwise let the copy occurs. copy2 will raise an error
                     if os.path.isdir(srcname):
                         copytree(srcname, dstname, symlinks, ignore,
                                  copy_function)
                     else:
                         copy_function(srcname, dstname)
             elif os.path.isdir(srcname):
                 copytree(srcname, dstname, symlinks, ignore, copy_function)
             else:
                 # Will raise a SpecialFileError for unsupported file types
                 copy_function(srcname, dstname)
         # catch the Error from the recursive copytree so that we can
         # continue with other files
         except Error as err:
             errors.extend(err.args[0])
         except OSError as why:
             errors.append((srcname, dstname, str(why)))
     try:
         copystat(src, dst)
     except OSError as why:
         # Copying file access times may fail on Windows
         if getattr(why, 'winerror', None) is None:
             errors.append((src, dst, str(why)))
     if errors:
         raise Error(errors)
     return dst

 # version vulnerable to race conditions

source code

　　9、rmtree(path, ignore_errors=False, onerror=None)

　　递归的删除文件

 def rmtree(path, ignore_errors=False, onerror=None):
     """Recursively delete a directory tree.

     If ignore_errors is set, errors are ignored; otherwise, if onerror
     is set, it is called to handle the error with arguments (func,
     path, exc_info) where func is platform and implementation dependent;
     path is the argument to that function that caused it to fail; and
     exc_info is a tuple returned by sys.exc_info().  If ignore_errors
     is false and onerror is None, an exception is raised.

     """
     if ignore_errors:
         def onerror(*args):
             pass
     elif onerror is None:
         def onerror(*args):
             raise
     if _use_fd_functions:
         # While the unsafe rmtree works fine on bytes, the fd based does not.
         if isinstance(path, bytes):
             path = os.fsdecode(path)
         # Note: To guard against symlink races, we use the standard
         # lstat()/open()/fstat() trick.
         try:
             orig_st = os.lstat(path)
         except Exception:
             onerror(os.lstat, path, sys.exc_info())
             return
         try:
             fd = os.open(path, os.O_RDONLY)
         except Exception:
             onerror(os.lstat, path, sys.exc_info())
             return
         try:
             if os.path.samestat(orig_st, os.fstat(fd)):
                 _rmtree_safe_fd(fd, path, onerror)
                 try:
                     os.rmdir(path)
                 except OSError:
                     onerror(os.rmdir, path, sys.exc_info())
             else:
                 try:
                     # symlinks to directories are forbidden, see bug #1669
                     raise OSError("Cannot call rmtree on a symbolic link")
                 except OSError:
                     onerror(os.path.islink, path, sys.exc_info())
         finally:
             os.close(fd)
     else:
         return _rmtree_unsafe(path, onerror)

source code

　　10、move(src, dst, copy_function=copy2)

　　递归的移动文件

 def move(src, dst, copy_function=copy2):
     """Recursively move a file or directory to another location. This is
     similar to the Unix "mv" command. Return the file or directory's
     destination.

     If the destination is a directory or a symlink to a directory, the source
     is moved inside the directory. The destination path must not already
     exist.

     If the destination already exists but is not a directory, it may be
     overwritten depending on os.rename() semantics.

     If the destination is on our current filesystem, then rename() is used.
     Otherwise, src is copied to the destination and then removed. Symlinks are
     recreated under the new name if os.rename() fails because of cross
     filesystem renames.

     The optional `copy_function` argument is a callable that will be used
     to copy the source or it will be delegated to `copytree`.
     By default, copy2() is used, but any function that supports the same
     signature (like copy()) can be used.

     A lot more could be done here...  A look at a mv.c shows a lot of
     the issues this implementation glosses over.

     """
     real_dst = dst
     if os.path.isdir(dst):
         if _samefile(src, dst):
             # We might be on a case insensitive filesystem,
             # perform the rename anyway.
             os.rename(src, dst)
             return

         real_dst = os.path.join(dst, _basename(src))
         if os.path.exists(real_dst):
             raise Error("Destination path '%s' already exists" % real_dst)
     try:
         os.rename(src, real_dst)
     except OSError:
         if os.path.islink(src):
             linkto = os.readlink(src)
             os.symlink(linkto, real_dst)
             os.unlink(src)
         elif os.path.isdir(src):
             if _destinsrc(src, dst):
                 raise Error("Cannot move a directory '%s' into itself"
                             " '%s'." % (src, dst))
             copytree(src, real_dst, copy_function=copy_function,
                      symlinks=True)
             rmtree(src)
         else:
             copy_function(src, real_dst)
             os.unlink(src)
     return real_dst

source code

　　11、get_archive_formats()

　　返回用于存档支持的格式

 def get_archive_formats():
     """Returns a list of supported formats for archiving and unarchiving.

     Each element of the returned sequence is a tuple (name, description)
     """
     formats = [(name, registry[2]) for name, registry in
                _ARCHIVE_FORMATS.items()]
     formats.sort()
     return formats

source code

　　12、register_archive_format(name, function, extra_args=None, description='')

　　注册档案格式（没有使用过），可以自定义压缩种类、调用程序以及相关描述。调用get_archive_formats()会返回相应数据。

 def register_archive_format(name, function, extra_args=None, description=''):
     """Registers an archive format.

     name is the name of the format. function is the callable that will be
     used to create archives. If provided, extra_args is a sequence of
     (name, value) tuples that will be passed as arguments to the callable.
     description can be provided to describe the format, and will be returned
     by the get_archive_formats() function.
     """
     if extra_args is None:
         extra_args = []
     if not callable(function):
         raise TypeError('The %s object is not callable' % function)
     if not isinstance(extra_args, (tuple, list)):
         raise TypeError('extra_args needs to be a sequence')
     for element in extra_args:
         if not isinstance(element, (tuple, list)) or len(element) !=2:
             raise TypeError('extra_args elements are : (arg_name, value)')

     _ARCHIVE_FORMATS[name] = (function, extra_args, description)

source code

　　13、unregister_archive_format(name)

　　删除压缩包种类

　　14、make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,dry_run=0, owner=None, group=None, logger=None)

　　创建压缩包并返回文件路径

　　base_name：文件名，如果没有路径，保存在当前路径下

　　format：压缩包种类，“zip”“tar”“bztar”“gztar”

　　root_dir：要压缩文件夹路径（默认当前目录）

　　owner：用户，默认为当前用户

　　group：组，默认为当前组

　　logger：日志记录

 def make_archive(base_name, format, root_dir=None, base_dir=None, verbose=0,
                  dry_run=0, owner=None, group=None, logger=None):
     """Create an archive file (eg. zip or tar).

     'base_name' is the name of the file to create, minus any format-specific
     extension; 'format' is the archive format: one of "zip", "tar", "bztar"
     or "gztar".

     'root_dir' is a directory that will be the root directory of the
     archive; ie. we typically chdir into 'root_dir' before creating the
     archive.  'base_dir' is the directory where we start archiving from;
     ie. 'base_dir' will be the common prefix of all files and
     directories in the archive.  'root_dir' and 'base_dir' both default
     to the current directory.  Returns the name of the archive file.

     'owner' and 'group' are used when creating a tar archive. By default,
     uses the current owner and group.
     """
     save_cwd = os.getcwd()
     if root_dir is not None:
         if logger is not None:
             logger.debug("changing into '%s'", root_dir)
         base_name = os.path.abspath(base_name)
         if not dry_run:
             os.chdir(root_dir)

     if base_dir is None:
         base_dir = os.curdir

     kwargs = {'dry_run': dry_run, 'logger': logger}

     try:
         format_info = _ARCHIVE_FORMATS[format]
     except KeyError:
         raise ValueError("unknown archive format '%s'" % format)

     func = format_info[0]
     for arg, val in format_info[1]:
         kwargs[arg] = val

     if format != 'zip':
         kwargs['owner'] = owner
         kwargs['group'] = group

     try:
         filename = func(base_name, base_dir, **kwargs)
     finally:
         if root_dir is not None:
             if logger is not None:
                 logger.debug("changing back to '%s'", save_cwd)
             os.chdir(save_cwd)

     return filename

source code

　　15、get_unpack_formats()

　　返回解压缩包的类型

　　16、register_unpack_format(name, extensions, function, extra_args=None,description='')

　　注册解压缩包的类型

　　17、unregister_unpack_format(name)

　　取消解压缩包类型的注册

　　18、unpack_archive(filename, extract_dir=None, format=None)

　　解压缩命令，没有返回值

 def unpack_archive(filename, extract_dir=None, format=None):
     """Unpack an archive.

     `filename` is the name of the archive.

     `extract_dir` is the name of the target directory, where the archive
     is unpacked. If not provided, the current working directory is used.

     `format` is the archive format: one of "zip", "tar", or "gztar". Or any
     other registered format. If not provided, unpack_archive will use the
     filename extension and see if an unpacker was registered for that
     extension.

     In case none is found, a ValueError is raised.
     """
     if extract_dir is None:
         extract_dir = os.getcwd()

     if format is not None:
         try:
             format_info = _UNPACK_FORMATS[format]
         except KeyError:
             raise ValueError("Unknown unpack format '{0}'".format(format))

         func = format_info[1]
         func(filename, extract_dir, **dict(format_info[2]))
     else:
         # we need to look at the registered unpackers supported extensions
         format = _find_unpack_format(filename)
         if format is None:
             raise ReadError("Unknown archive format '{0}'".format(filename))

         func = _UNPACK_FORMATS[format][1]
         kwargs = dict(_UNPACK_FORMATS[format][2])
         func(filename, extract_dir, **kwargs)

source code

　　19、chown(path, user=None, group=None)

　　改变文件或目录的用户及属组信息

 def chown(path, user=None, group=None):
     """Change owner user and group of the given path.

     user and group can be the uid/gid or the user/group names, and in that case,
     they are converted to their respective uid/gid.
     """

     if user is None and group is None:
         raise ValueError("user and/or group must be set")

     _user = user
     _group = group

     # -1 means don't change it
     if user is None:
         _user = -1
     # user can either be an int (the uid) or a string (the system username)
     elif isinstance(user, str):
         _user = _get_uid(user)
         if _user is None:
             raise LookupError("no such user: {!r}".format(user))

     if group is None:
         _group = -1
     elif not isinstance(group, int):
         _group = _get_gid(group)
         if _group is None:
             raise LookupError("no such group: {!r}".format(group))

     os.chown(path, _user, _group)

source code

　　20、get_terminal_size(fallback=(80, 24))

　　获取终端大小，默认为（80，24）

　　21、which(cmd, mode=os.F_OK | os.X_OK, path=None)

　　返回命令的路径，可以自定义路径，否则使用os.environ.get（“PATH”）路径。如果没有找到返回None