Example of common file operation functions of the shutil module in Python,

Example of common file operation functions of the shutil module in Python,

The OS module allows you to create, delete, and view file attributes for directories or files, as well as perform path operations on files and directories. For example: absolute path, parent directory ...... However, OS file operations should also include operations such as mobile copy, packaging, compression, and decompression, which are not provided by these OS modules.
The shutil mentioned in this article is a supplement to file operations in OS. -- Compress and decompress mobile copy packages,
Shutil functions:
1 shutil. copyfileobj (fsrc, fdst [, length = 16*1024])
Copy the file content to another file. You can copy the content of the specified size.
Let's take a look at its source code.

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)

Note! Fsrc and fdst are all file objects and must be opened before copying.

import shutilf1=open('name','r')f2=open('name_copy','w+')shutil.copyfileobj(f1,f2,length=16*1024)

 
2 shutil. copyfile (src, dst)
Is it difficult to copy the file content? You also need to manually use the open function to open the file, which is not needed here. In fact, copyfile calls copyfileobj.

def copyfile(src, dst, *, follow_symlinks=True):  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

Shutil. copyfile ('name', 'name _ copy_2 ') # You can copy the file content in one sentence.

3 shutil. copymode (src, dst)
Only copy permission, without changing the file content, group and user.

def copymode(src, dst, *, follow_symlinks=True):  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))

First read the permissions of the two files

[root@slyoyo python_test]# ls -ltotal 4-rw-r--r--. 1 root root 79 May 14 05:17 test1-rwxr-xr-x. 1 root root 0 May 14 19:10 test2

Run commands

>>> import shutil>>> shutil.copymode('test1','test2')

View results

[root@slyoyo python_test]# ls -ltotal 4-rw-r--r--. 1 root root 79 May 14 05:17 test1-rw-r--r--. 1 root root 0 May 14 19:10 test2

An error is reported when we change the target file to a non-existent file.

>>> shutil.copymode('test1','test3')  Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/local/python/lib/python3.4/shutil.py", line 132, in copymode  chmod_func(dst, stat.S_IMODE(st.st_mode))FileNotFoundError: [Errno 2] No such file or directory: 'test233'

4 shutil. copystat (src, dst)
Copy all status information, including permissions, groups, users, and time.

def copystat(src, dst, *, follow_symlinks=True):  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)

 
5 shutil. copy (src, dst)
Copy the content and permissions of the file, first copyfile and then copymode

 def copy(src, dst, *, follow_symlinks=True):  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

6 shutil. copy2 (src, dst)
Copy the content of the file and all the status information of the file. Copyfile first and copystat

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

 
7 shutil. copytree (src, dst, symlinks = False, ignore = None, copy_function = copy2, ignore_dangling_symlinks = False)
Recursive copy file content and status information

def copytree(src, dst, symlinks=False, ignore=None, copy_function=copy2,       ignore_dangling_symlinks=False):  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

[root@slyoyo python_test]# tree copytree_test/copytree_test/└── test  ├── test1  ├── test2  └── hahaha[root@slyoyo test]# ls -ltotal 0-rw-r--r--. 1 python python 0 May 14 19:36 hahaha-rw-r--r--. 1 python python 0 May 14 19:36 test1-rw-r--r--. 1 root  root  0 May 14 19:36 test2>>> shutil.copytree('copytree_test','copytree_copy')'copytree_copy'[root@slyoyo python_test]# ls -ltotal 12drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copydrwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_test-rw-r--r--. 1 python python  79 May 14 05:17 test1-rw-r--r--. 1 root  root   0 May 14 19:10 test2[root@slyoyo python_test]# tree copytree_copy/copytree_copy/└── test  ├── hahaha  ├── test1  └── test2

 
8 shutil. rmtree (path, ignore_errors = False, onerror = None)
Recursively delete an object

def rmtree(path, ignore_errors=False, onerror=None):  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)

 
9 shutil. move (src, dst)
Recursively move a file

def move(src, dst):  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, symlinks=True)      rmtree(src)    else:      copy2(src, real_dst)      os.unlink(src)  return real_dst

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

Compress and Package

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

 
Base_name: Name or path name of the compressed package
Format: compression or packaging format: "zip", "tar", "bztar" or "gztar"
Root_dir: directory or file to be packaged (that is, the source file)
 

>>> shutil.make_archive('tarball','gztar',root_dir='copytree_test')[root@slyoyo python_test]# ls -ltotal 12drwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_copydrwxr-xr-x. 3 root  root  4096 May 14 19:36 copytree_test-rw-r--r--. 1 root  root   0 May 14 21:12 tarball.tar.gz-rw-r--r--. 1 python python  79 May 14 05:17 test1-rw-r--r--. 1 root  root   0 May 14 19:10 test2