Merge branch 'jk/fsck-doc'
[git/git.git] / Documentation / git-fsck.txt
1 git-fsck(1)
2 ===========
3
4 NAME
5 ----
6 git-fsck - Verifies the connectivity and validity of the objects in the database
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git fsck' [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
13 [--[no-]full] [--strict] [--verbose] [--lost-found]
14 [--[no-]dangling] [--[no-]progress] [--connectivity-only]
15 [--[no-]name-objects] [<object>*]
16
17 DESCRIPTION
18 -----------
19 Verifies the connectivity and validity of the objects in the database.
20
21 OPTIONS
22 -------
23 <object>::
24 An object to treat as the head of an unreachability trace.
25 +
26 If no objects are given, 'git fsck' defaults to using the
27 index file, all SHA-1 references in `refs` namespace, and all reflogs
28 (unless --no-reflogs is given) as heads.
29
30 --unreachable::
31 Print out objects that exist but that aren't reachable from any
32 of the reference nodes.
33
34 --[no-]dangling::
35 Print objects that exist but that are never 'directly' used (default).
36 `--no-dangling` can be used to omit this information from the output.
37
38 --root::
39 Report root nodes.
40
41 --tags::
42 Report tags.
43
44 --cache::
45 Consider any object recorded in the index also as a head node for
46 an unreachability trace.
47
48 --no-reflogs::
49 Do not consider commits that are referenced only by an
50 entry in a reflog to be reachable. This option is meant
51 only to search for commits that used to be in a ref, but
52 now aren't, but are still in that corresponding reflog.
53
54 --full::
55 Check not just objects in GIT_OBJECT_DIRECTORY
56 ($GIT_DIR/objects), but also the ones found in alternate
57 object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES
58 or $GIT_DIR/objects/info/alternates,
59 and in packed Git archives found in $GIT_DIR/objects/pack
60 and corresponding pack subdirectories in alternate
61 object pools. This is now default; you can turn it off
62 with --no-full.
63
64 --connectivity-only::
65 Check only the connectivity of reachable objects, making sure
66 that any objects referenced by a reachable tag, commit, or tree
67 is present. This speeds up the operation by avoiding reading
68 blobs entirely (though it does still check that referenced blobs
69 exist). This will detect corruption in commits and trees, but
70 not do any semantic checks (e.g., for format errors). Corruption
71 in blob objects will not be detected at all.
72 +
73 Unreachable tags, commits, and trees will also be accessed to find the
74 tips of dangling segments of history. Use `--no-dangling` if you don't
75 care about this output and want to speed it up further.
76
77 --strict::
78 Enable more strict checking, namely to catch a file mode
79 recorded with g+w bit set, which was created by older
80 versions of Git. Existing repositories, including the
81 Linux kernel, Git itself, and sparse repository have old
82 objects that triggers this check, but it is recommended
83 to check new projects with this flag.
84
85 --verbose::
86 Be chatty.
87
88 --lost-found::
89 Write dangling objects into .git/lost-found/commit/ or
90 .git/lost-found/other/, depending on type. If the object is
91 a blob, the contents are written into the file, rather than
92 its object name.
93
94 --name-objects::
95 When displaying names of reachable objects, in addition to the
96 SHA-1 also display a name that describes *how* they are reachable,
97 compatible with linkgit:git-rev-parse[1], e.g.
98 `HEAD@{1234567890}~25^2:src/`.
99
100 --[no-]progress::
101 Progress status is reported on the standard error stream by
102 default when it is attached to a terminal, unless
103 --no-progress or --verbose is specified. --progress forces
104 progress status even if the standard error stream is not
105 directed to a terminal.
106
107 DISCUSSION
108 ----------
109
110 git-fsck tests SHA-1 and general object sanity, and it does full tracking
111 of the resulting reachability and everything else. It prints out any
112 corruption it finds (missing or bad objects), and if you use the
113 `--unreachable` flag it will also print out objects that exist but that
114 aren't reachable from any of the specified head nodes (or the default
115 set, as mentioned above).
116
117 Any corrupt objects you will have to find in backups or other archives
118 (i.e., you can just remove them and do an 'rsync' with some other site in
119 the hopes that somebody else has the object you have corrupted).
120
121 If core.commitGraph is true, the commit-graph file will also be inspected
122 using 'git commit-graph verify'. See linkgit:git-commit-graph[1].
123
124 Extracted Diagnostics
125 ---------------------
126
127 expect dangling commits - potential heads - due to lack of head information::
128 You haven't specified any nodes as heads so it won't be
129 possible to differentiate between un-parented commits and
130 root nodes.
131
132 missing sha1 directory '<dir>'::
133 The directory holding the sha1 objects is missing.
134
135 unreachable <type> <object>::
136 The <type> object <object>, isn't actually referred to directly
137 or indirectly in any of the trees or commits seen. This can
138 mean that there's another root node that you're not specifying
139 or that the tree is corrupt. If you haven't missed a root node
140 then you might as well delete unreachable nodes since they
141 can't be used.
142
143 missing <type> <object>::
144 The <type> object <object>, is referred to but isn't present in
145 the database.
146
147 dangling <type> <object>::
148 The <type> object <object>, is present in the database but never
149 'directly' used. A dangling commit could be a root node.
150
151 hash mismatch <object>::
152 The database has an object whose hash doesn't match the
153 object database value.
154 This indicates a serious data integrity problem.
155
156 Environment Variables
157 ---------------------
158
159 GIT_OBJECT_DIRECTORY::
160 used to specify the object database root (usually $GIT_DIR/objects)
161
162 GIT_INDEX_FILE::
163 used to specify the index file of the index
164
165 GIT_ALTERNATE_OBJECT_DIRECTORIES::
166 used to specify additional object database roots (usually unset)
167
168 GIT
169 ---
170 Part of the linkgit:git[1] suite