doc/git-fsck: change the way for getting heads' SHA1s
[git/git.git] / Documentation / git-fsck.txt
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1git-fsck(1)
2===========
3
4NAME
5----
6git-fsck - Verifies the connectivity and validity of the objects in the database
7
8
9SYNOPSIS
10--------
11[verse]
b1889c36 12'git fsck' [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
68f6c019 13 [--full] [--strict] [--verbose] [--lost-found] [<object>*]
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14
15DESCRIPTION
16-----------
17Verifies the connectivity and validity of the objects in the database.
18
19OPTIONS
20-------
21<object>::
22 An object to treat as the head of an unreachability trace.
23+
ba020ef5 24If no objects are given, 'git-fsck' defaults to using the
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25index file, all SHA1 references in .git/refs/*, and all reflogs (unless
26--no-reflogs is given) as heads.
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27
28--unreachable::
29 Print out objects that exist but that aren't readable from any
30 of the reference nodes.
31
32--root::
33 Report root nodes.
34
35--tags::
36 Report tags.
37
38--cache::
39 Consider any object recorded in the index also as a head node for
40 an unreachability trace.
41
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42--no-reflogs::
43 Do not consider commits that are referenced only by an
44 entry in a reflog to be reachable. This option is meant
45 only to search for commits that used to be in a ref, but
46 now aren't, but are still in that corresponding reflog.
47
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48--full::
49 Check not just objects in GIT_OBJECT_DIRECTORY
50 ($GIT_DIR/objects), but also the ones found in alternate
51 object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES
52 or $GIT_DIR/objects/info/alternates,
53 and in packed git archives found in $GIT_DIR/objects/pack
54 and corresponding pack subdirectories in alternate
55 object pools.
56
57--strict::
58 Enable more strict checking, namely to catch a file mode
59 recorded with g+w bit set, which was created by older
60 versions of git. Existing repositories, including the
61 Linux kernel, git itself, and sparse repository have old
62 objects that triggers this check, but it is recommended
63 to check new projects with this flag.
64
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65--verbose::
66 Be chatty.
67
68f6c019 68--lost-found::
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69 Write dangling objects into .git/lost-found/commit/ or
70 .git/lost-found/other/, depending on type. If the object is
71 a blob, the contents are written into the file, rather than
72 its object name.
68f6c019 73
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74It tests SHA1 and general object sanity, and it does full tracking of
75the resulting reachability and everything else. It prints out any
76corruption it finds (missing or bad objects), and if you use the
77'--unreachable' flag it will also print out objects that exist but
78that aren't readable from any of the specified head nodes.
79
80So for example
81
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82 git fsck --unreachable HEAD \
83 $(git for-each-ref --format="%(objectname)" refs/heads)
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84
85will do quite a _lot_ of verification on the tree. There are a few
86extra validity tests to be added (make sure that tree objects are
ba020ef5 87sorted properly etc), but on the whole if 'git-fsck' is happy, you
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88do have a valid tree.
89
90Any corrupt objects you will have to find in backups or other archives
2fd02c92 91(i.e., you can just remove them and do an 'rsync' with some other site in
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92the hopes that somebody else has the object you have corrupted).
93
94Of course, "valid tree" doesn't mean that it wasn't generated by some
95evil person, and the end result might be crap. git is a revision
96tracking system, not a quality assurance system ;)
97
98Extracted Diagnostics
99---------------------
100
101expect dangling commits - potential heads - due to lack of head information::
102 You haven't specified any nodes as heads so it won't be
103 possible to differentiate between un-parented commits and
104 root nodes.
105
106missing sha1 directory '<dir>'::
107 The directory holding the sha1 objects is missing.
108
109unreachable <type> <object>::
110 The <type> object <object>, isn't actually referred to directly
111 or indirectly in any of the trees or commits seen. This can
112 mean that there's another root node that you're not specifying
113 or that the tree is corrupt. If you haven't missed a root node
114 then you might as well delete unreachable nodes since they
115 can't be used.
116
117missing <type> <object>::
118 The <type> object <object>, is referred to but isn't present in
119 the database.
120
121dangling <type> <object>::
122 The <type> object <object>, is present in the database but never
123 'directly' used. A dangling commit could be a root node.
124
125warning: git-fsck: tree <tree> has full pathnames in it::
126 And it shouldn't...
127
128sha1 mismatch <object>::
129 The database has an object who's sha1 doesn't match the
130 database value.
131 This indicates a serious data integrity problem.
132
133Environment Variables
134---------------------
135
136GIT_OBJECT_DIRECTORY::
137 used to specify the object database root (usually $GIT_DIR/objects)
138
139GIT_INDEX_FILE::
140 used to specify the index file of the index
141
142GIT_ALTERNATE_OBJECT_DIRECTORIES::
143 used to specify additional object database roots (usually unset)
144
145Author
146------
147Written by Linus Torvalds <torvalds@osdl.org>
148
149Documentation
150--------------
151Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
152
153GIT
154---
9e1f0a85 155Part of the linkgit:git[1] suite