Doc/lib/libshutil.tex

   1 \section{\module{shutil} ---
   2          High-level file operations}
   3
   4 \declaremodule{standard}{shutil}
   5 \modulesynopsis{High-level file operations, including copying.}
   6 \sectionauthor{Fred L. Drake, Jr.}{fdrake@acm.org}
   7 % partly based on the docstrings
   8
   9
  10 The \module{shutil} module offers a number of high-level operations on
  11 files and collections of files.  In particular, functions are provided
  12 which support file copying and removal.
  13 \index{file!copying}
  14 \index{copying files}
  15
  16 \strong{Caveat:}  On MacOS, the resource fork and other metadata are
  17 not used.  For file copies, this means that resources will be lost and
  18 file type and creator codes will not be correct.
  19
  20
  21 \begin{funcdesc}{copyfile}{src, dst}
  22   Copy the contents of the file named \var{src} to a file named
  23   \var{dst}.  If \var{dst} exists, it will be replaced, otherwise it
  24   will be created.
  25 \end{funcdesc}
  26
  27 \begin{funcdesc}{copyfileobj}{fsrc, fdst\optional{, length}}
  28   Copy the contents of the file-like object \var{fsrc} to the
  29   file-like object \var{fdst}.  The integer \var{length}, if given,
  30   is the buffer size. In particular, a negative \var{length} value
  31   means to copy the data without looping over the source data in
  32   chunks; by default the data is read in chunks to avoid uncontrolled
  33   memory consumption.
  34 \end{funcdesc}
  35
  36 \begin{funcdesc}{copymode}{src, dst}
  37   Copy the permission bits from \var{src} to \var{dst}.  The file
  38   contents, owner, and group are unaffected.
  39 \end{funcdesc}
  40
  41 \begin{funcdesc}{copystat}{src, dst}
  42   Copy the permission bits, last access time, and last modification
  43   time from \var{src} to \var{dst}.  The file contents, owner, and
  44   group are unaffected.
  45 \end{funcdesc}
  46
  47 \begin{funcdesc}{copy}{src, dst}
  48   Copy the file \var{src} to the file or directory \var{dst}.  If
  49   \var{dst} is a directory, a file with the same basename as \var{src}
  50   is created (or overwritten) in the directory specified.  Permission
  51   bits are copied.
  52 \end{funcdesc}
  53
  54 \begin{funcdesc}{copy2}{src, dst}
  55   Similar to \function{copy()}, but last access time and last
  56   modification time are copied as well.  This is similar to the
  57   \UNIX{} command \program{cp} \programopt{-p}.
  58 \end{funcdesc}
  59
  60 \begin{funcdesc}{copytree}{src, dst\optional{, symlinks}}
  61   Recursively copy an entire directory tree rooted at \var{src}.  The
  62   destination directory, named by \var{dst}, must not already exist;
  63   it will be created.  Individual files are copied using
  64   \function{copy2()}.  If \var{symlinks} is true, symbolic links in
  65   the source tree are represented as symbolic links in the new tree;
  66   if false or omitted, the contents of the linked files are copied to
  67   the new tree.  Errors are reported to standard output.
  68
  69   The source code for this should be considered an example rather than
  70   a tool.
  71 \end{funcdesc}
  72
  73 \begin{funcdesc}{rmtree}{path\optional{, ignore_errors\optional{, onerror}}}
  74 \index{directory!deleting}
  75   Delete an entire directory tree.  If \var{ignore_errors} is true,
  76   errors will be ignored; if false or omitted, errors are handled by
  77   calling a handler specified by \var{onerror} or raise an exception.
  78
  79   If \var{onerror} is provided, it must be a callable that accepts
  80   three parameters: \var{function}, \var{path}, and \var{excinfo}.
  81   The first parameter, \var{function}, is the function which raised
  82   the exception; it will be \function{os.remove()} or
  83   \function{os.rmdir()}.  The second parameter, \var{path}, will be
  84   the path name passed to \var{function}.  The third parameter,
  85   \var{excinfo}, will be the exception information return by
  86   \function{sys.exc_info()}.  Exceptions raised by \var{onerror} will
  87   not be caught.
  88 \end{funcdesc}
  89
  90
  91 \subsection{Example \label{shutil-example}}
  92
  93 This example is the implementation of the \function{copytree()}
  94 function, described above, with the docstring omitted.  It
  95 demonstrates many of the other functions provided by this module.
  96
  97 \begin{verbatim}
  98 def copytree(src, dst, symlinks=0):
  99     names = os.listdir(src)
 100     os.mkdir(dst)
 101     for name in names:
 102         srcname = os.path.join(src, name)
 103         dstname = os.path.join(dst, name)
 104         try:
 105             if symlinks and os.path.islink(srcname):
 106                 linkto = os.readlink(srcname)
 107                 os.symlink(linkto, dstname)
 108             elif os.path.isdir(srcname):
 109                 copytree(srcname, dstname)
 110             else:
 111                 copy2(srcname, dstname)
 112             # XXX What about devices, sockets etc.?
 113         except (IOError, os.error), why:
 114             print "Can't copy %s to %s: %s" % (`srcname`, `dstname`, str(why))
 115 \end{verbatim}