Documentation / git-fsck-objects.txton commit [PATCH] fetch.c: Make process() look at each object only once (f9cff26)
   1git-fsck-objects(1)
   2===================
   3v0.1, May 2005
   4
   5NAME
   6----
   7git-fsck-objects - Verifies the connectivity and validity of the objects in the database
   8
   9
  10SYNOPSIS
  11--------
  12'git-fsck-objects' [--tags] [--root] [--unreachable] [--cache] [--standalone | --full] [--strict] [<object>*]
  13
  14DESCRIPTION
  15-----------
  16Verifies the connectivity and validity of the objects in the database.
  17
  18OPTIONS
  19-------
  20<object>::
  21        An object to treat as the head of an unreachability trace.
  22
  23        If no objects are given, git-fsck-objects defaults to using the
  24        index file and all SHA1 references in .git/refs/* as heads.
  25
  26--unreachable::
  27        Print out objects that exist but that aren't readable from any
  28        of the reference nodes.
  29
  30--root::
  31        Report root nodes.
  32
  33--tags::
  34        Report tags.
  35
  36--cache::
  37        Consider any object recorded in the cache also as a head node for
  38        an unreachability trace.
  39
  40--standalone::
  41        Limit checks to the contents of GIT_OBJECT_DIRECTORY
  42        ($GIT_DIR/objects), making sure that it is consistent and
  43        complete without referring to objects found in alternate
  44        object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES,
  45        nor packed GIT archives found in $GIT_DIR/objects/pack;
  46        cannot be used with --full.
  47
  48--full::
  49        Check not just objects in GIT_OBJECT_DIRECTORY
  50        ($GIT_DIR/objects), but also the ones found in alternate
  51        object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES,
  52        and in packed GIT archives found in $GIT_DIR/objects/pack
  53        and corresponding pack subdirectories in alternate
  54        object pools; cannot be used with --standalone.
  55
  56--strict::
  57        Enable more strict checking, namely to catch a file mode
  58        recorded with g+w bit set, which was created by older
  59        versions of GIT.  Existing repositories, including the
  60        Linux kernel, GIT itself, and sparse repository have old
  61        objects that triggers this check, but it is recommended
  62        to check new projects with this flag.
  63
  64It tests SHA1 and general object sanity, and it does full tracking of
  65the resulting reachability and everything else. It prints out any
  66corruption it finds (missing or bad objects), and if you use the
  67'--unreachable' flag it will also print out objects that exist but
  68that aren't readable from any of the specified head nodes.
  69
  70So for example
  71
  72        git-fsck-objects --unreachable $(cat .git/HEAD .git/refs/heads/*)
  73
  74will do quite a _lot_ of verification on the tree. There are a few
  75extra validity tests to be added (make sure that tree objects are
  76sorted properly etc), but on the whole if "git-fsck-objects" is happy, you
  77do have a valid tree.
  78
  79Any corrupt objects you will have to find in backups or other archives
  80(ie you can just remove them and do an "rsync" with some other site in
  81the hopes that somebody else has the object you have corrupted).
  82
  83Of course, "valid tree" doesn't mean that it wasn't generated by some
  84evil person, and the end result might be crap. Git is a revision
  85tracking system, not a quality assurance system ;)
  86
  87Extracted Diagnostics
  88---------------------
  89
  90expect dangling commits - potential heads - due to lack of head information::
  91        You haven't specified any nodes as heads so it won't be
  92        possible to differentiate between un-parented commits and
  93        root nodes.
  94
  95missing sha1 directory '<dir>'::
  96        The directory holding the sha1 objects is missing.
  97
  98unreachable <type> <object>::
  99        The <type> object <object>, isn't actually referred to directly
 100        or indirectly in any of the trees or commits seen. This can
 101        mean that there's another root node that you're not specifying
 102        or that the tree is corrupt. If you haven't missed a root node
 103        then you might as well delete unreachable nodes since they
 104        can't be used.
 105
 106missing <type> <object>::
 107        The <type> object <object>, is referred to but isn't present in
 108        the database.
 109
 110dangling <type> <object>::
 111        The <type> object <object>, is present in the database but never
 112        'directly' used. A dangling commit could be a root node.
 113
 114warning: git-fsck-objects: tree <tree> has full pathnames in it::
 115        And it shouldn't...
 116
 117sha1 mismatch <object>::
 118        The database has an object who's sha1 doesn't match the
 119        database value.
 120        This indicates a serious data integrity problem.
 121
 122Environment Variables
 123---------------------
 124
 125GIT_OBJECT_DIRECTORY::
 126        used to specify the object database root (usually $GIT_DIR/objects)
 127
 128GIT_INDEX_FILE::
 129        used to specify the index file of the cache
 130
 131GIT_ALTERNATE_OBJECT_DIRECTORIES:
 132        used to specify additional object database roots (usually unset)
 133
 134Author
 135------
 136Written by Linus Torvalds <torvalds@osdl.org>
 137
 138Documentation
 139--------------
 140Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
 141
 142GIT
 143---
 144Part of the gitlink:git[7] suite
 145