2 :mod:`filecmp` --- File and Directory Comparisons
3 =================================================
6 :synopsis: Compare files efficiently.
7 .. sectionauthor:: Moshe Zadka <moshez@zadka.site.co.il>
10 The :mod:`filecmp` module defines functions to compare files and directories,
11 with various optional time/correctness trade-offs. For comparing files,
12 see also the :mod:`difflib` module.
14 The :mod:`filecmp` module defines the following functions:
17 .. function:: cmp(f1, f2[, shallow])
19 Compare the files named *f1* and *f2*, returning ``True`` if they seem equal,
22 Unless *shallow* is given and is false, files with identical :func:`os.stat`
23 signatures are taken to be equal.
25 Files that were compared using this function will not be compared again unless
26 their :func:`os.stat` signature changes.
28 Note that no external programs are called from this function, giving it
29 portability and efficiency.
32 .. function:: cmpfiles(dir1, dir2, common[, shallow])
34 Compare the files in the two directories *dir1* and *dir2* whose names are
37 Returns three lists of file names: *match*, *mismatch*,
38 *errors*. *match* contains the list of files that match, *mismatch* contains
39 the names of those that don't, and *errors* lists the names of files which
40 could not be compared. Files are listed in *errors* if they don't exist in
41 one of the directories, the user lacks permission to read them or if the
42 comparison could not be done for some other reason.
44 The *shallow* parameter has the same meaning and default value as for
47 For example, ``cmpfiles('a', 'b', ['c', 'd/e'])`` will compare ``a/c`` with
48 ``b/c`` and ``a/d/e`` with ``b/d/e``. ``'c'`` and ``'d/e'`` will each be in
49 one of the three returned lists.
55 >>> filecmp.cmp('undoc.rst', 'undoc.rst')
57 >>> filecmp.cmp('undoc.rst', 'index.rst')
63 The :class:`dircmp` class
64 -------------------------
66 :class:`dircmp` instances are built using this constructor:
69 .. class:: dircmp(a, b[, ignore[, hide]])
71 Construct a new directory comparison object, to compare the directories *a* and
72 *b*. *ignore* is a list of names to ignore, and defaults to ``['RCS', 'CVS',
73 'tags']``. *hide* is a list of names to hide, and defaults to ``[os.curdir,
76 The :class:`dircmp` class provides the following methods:
81 Print (to ``sys.stdout``) a comparison between *a* and *b*.
84 .. method:: report_partial_closure()
86 Print a comparison between *a* and *b* and common immediate
90 .. method:: report_full_closure()
92 Print a comparison between *a* and *b* and common subdirectories
95 The :class:`dircmp` offers a number of interesting attributes that may be
96 used to get various bits of information about the directory trees being
99 Note that via :meth:`__getattr__` hooks, all attributes are computed lazily,
100 so there is no speed penalty if only those attributes which are lightweight
104 .. attribute:: left_list
106 Files and subdirectories in *a*, filtered by *hide* and *ignore*.
109 .. attribute:: right_list
111 Files and subdirectories in *b*, filtered by *hide* and *ignore*.
114 .. attribute:: common
116 Files and subdirectories in both *a* and *b*.
119 .. attribute:: left_only
121 Files and subdirectories only in *a*.
124 .. attribute:: right_only
126 Files and subdirectories only in *b*.
129 .. attribute:: common_dirs
131 Subdirectories in both *a* and *b*.
134 .. attribute:: common_files
136 Files in both *a* and *b*
139 .. attribute:: common_funny
141 Names in both *a* and *b*, such that the type differs between the
142 directories, or names for which :func:`os.stat` reports an error.
145 .. attribute:: same_files
147 Files which are identical in both *a* and *b*.
150 .. attribute:: diff_files
152 Files which are in both *a* and *b*, whose contents differ.
155 .. attribute:: funny_files
157 Files which are in both *a* and *b*, but could not be compared.
160 .. attribute:: subdirs
162 A dictionary mapping names in :attr:`common_dirs` to :class:`dircmp` objects.