Documentation / git-fsck-objects.txton commit Merge part of np/delta (882e4dc)
   1git-fsck-objects(1)
   2===================
   3
   4NAME
   5----
   6git-fsck-objects - Verifies the connectivity and validity of the objects in the database
   7
   8
   9SYNOPSIS
  10--------
  11[verse]
  12'git-fsck-objects' [--tags] [--root] [--unreachable] [--cache]
  13                 [--standalone | --full] [--strict] [<object>*]
  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+
  24If no objects are given, git-fsck-objects defaults to using the
  25index file and all SHA1 references in .git/refs/* as heads.
  26
  27--unreachable::
  28        Print out objects that exist but that aren't readable from any
  29        of the reference nodes.
  30
  31--root::
  32        Report root nodes.
  33
  34--tags::
  35        Report tags.
  36
  37--cache::
  38        Consider any object recorded in the index also as a head node for
  39        an unreachability trace.
  40
  41--standalone::
  42        Limit checks to the contents of GIT_OBJECT_DIRECTORY
  43        ($GIT_DIR/objects), making sure that it is consistent and
  44        complete without referring to objects found in alternate
  45        object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES,
  46        nor packed git archives found in $GIT_DIR/objects/pack;
  47        cannot be used with --full.
  48
  49--full::
  50        Check not just objects in GIT_OBJECT_DIRECTORY
  51        ($GIT_DIR/objects), but also the ones found in alternate
  52        object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES,
  53        and in packed git archives found in $GIT_DIR/objects/pack
  54        and corresponding pack subdirectories in alternate
  55        object pools; cannot be used with --standalone.
  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
  65It tests SHA1 and general object sanity, and it does full tracking of
  66the resulting reachability and everything else. It prints out any
  67corruption it finds (missing or bad objects), and if you use the
  68'--unreachable' flag it will also print out objects that exist but
  69that aren't readable from any of the specified head nodes.
  70
  71So for example
  72
  73        git-fsck-objects --unreachable HEAD $(cat .git/refs/heads/*)
  74
  75will do quite a _lot_ of verification on the tree. There are a few
  76extra validity tests to be added (make sure that tree objects are
  77sorted properly etc), but on the whole if "git-fsck-objects" is happy, you
  78do have a valid tree.
  79
  80Any corrupt objects you will have to find in backups or other archives
  81(ie you can just remove them and do an "rsync" with some other site in
  82the hopes that somebody else has the object you have corrupted).
  83
  84Of course, "valid tree" doesn't mean that it wasn't generated by some
  85evil person, and the end result might be crap. git is a revision
  86tracking system, not a quality assurance system ;)
  87
  88Extracted Diagnostics
  89---------------------
  90
  91expect dangling commits - potential heads - due to lack of head information::
  92        You haven't specified any nodes as heads so it won't be
  93        possible to differentiate between un-parented commits and
  94        root nodes.
  95
  96missing sha1 directory '<dir>'::
  97        The directory holding the sha1 objects is missing.
  98
  99unreachable <type> <object>::
 100        The <type> object <object>, isn't actually referred to directly
 101        or indirectly in any of the trees or commits seen. This can
 102        mean that there's another root node that you're not specifying
 103        or that the tree is corrupt. If you haven't missed a root node
 104        then you might as well delete unreachable nodes since they
 105        can't be used.
 106
 107missing <type> <object>::
 108        The <type> object <object>, is referred to but isn't present in
 109        the database.
 110
 111dangling <type> <object>::
 112        The <type> object <object>, is present in the database but never
 113        'directly' used. A dangling commit could be a root node.
 114
 115warning: git-fsck-objects: tree <tree> has full pathnames in it::
 116        And it shouldn't...
 117
 118sha1 mismatch <object>::
 119        The database has an object who's sha1 doesn't match the
 120        database value.
 121        This indicates a serious data integrity problem.
 122
 123Environment Variables
 124---------------------
 125
 126GIT_OBJECT_DIRECTORY::
 127        used to specify the object database root (usually $GIT_DIR/objects)
 128
 129GIT_INDEX_FILE::
 130        used to specify the index file of the index
 131
 132GIT_ALTERNATE_OBJECT_DIRECTORIES::
 133        used to specify additional object database roots (usually unset)
 134
 135Author
 136------
 137Written by Linus Torvalds <torvalds@osdl.org>
 138
 139Documentation
 140--------------
 141Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
 142
 143GIT
 144---
 145Part of the gitlink:git[7] suite
 146