Documentation / git-fsck.txton commit rebase -i: squash should retain the authorship of the _first_ commit (81ab1cb)
   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]
  12'git-fsck' [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
  13         [--full] [--strict] [--verbose] [--lost-found] [<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 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--no-reflogs::
  42        Do not consider commits that are referenced only by an
  43        entry in a reflog to be reachable.  This option is meant
  44        only to search for commits that used to be in a ref, but
  45        now aren't, but are still in that corresponding reflog.
  46
  47--full::
  48        Check not just objects in GIT_OBJECT_DIRECTORY
  49        ($GIT_DIR/objects), but also the ones found in alternate
  50        object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES
  51        or $GIT_DIR/objects/info/alternates,
  52        and in packed git archives found in $GIT_DIR/objects/pack
  53        and corresponding pack subdirectories in alternate
  54        object pools.
  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
  64--verbose::
  65        Be chatty.
  66
  67--lost-found::
  68        Write dangling objects into .git/lost-found/commit/ or
  69        .git/lost-found/other/, depending on type.  If the object is
  70        a blob, the contents are written into the file, rather than
  71        its object name.
  72
  73It tests SHA1 and general object sanity, and it does full tracking of
  74the resulting reachability and everything else. It prints out any
  75corruption it finds (missing or bad objects), and if you use the
  76'--unreachable' flag it will also print out objects that exist but
  77that aren't readable from any of the specified head nodes.
  78
  79So for example
  80
  81        git-fsck --unreachable HEAD $(cat .git/refs/heads/*)
  82
  83will do quite a _lot_ of verification on the tree. There are a few
  84extra validity tests to be added (make sure that tree objects are
  85sorted properly etc), but on the whole if "git-fsck" is happy, you
  86do have a valid tree.
  87
  88Any corrupt objects you will have to find in backups or other archives
  89(i.e., you can just remove them and do an "rsync" with some other site in
  90the hopes that somebody else has the object you have corrupted).
  91
  92Of course, "valid tree" doesn't mean that it wasn't generated by some
  93evil person, and the end result might be crap. git is a revision
  94tracking system, not a quality assurance system ;)
  95
  96Extracted Diagnostics
  97---------------------
  98
  99expect dangling commits - potential heads - due to lack of head information::
 100        You haven't specified any nodes as heads so it won't be
 101        possible to differentiate between un-parented commits and
 102        root nodes.
 103
 104missing sha1 directory '<dir>'::
 105        The directory holding the sha1 objects is missing.
 106
 107unreachable <type> <object>::
 108        The <type> object <object>, isn't actually referred to directly
 109        or indirectly in any of the trees or commits seen. This can
 110        mean that there's another root node that you're not specifying
 111        or that the tree is corrupt. If you haven't missed a root node
 112        then you might as well delete unreachable nodes since they
 113        can't be used.
 114
 115missing <type> <object>::
 116        The <type> object <object>, is referred to but isn't present in
 117        the database.
 118
 119dangling <type> <object>::
 120        The <type> object <object>, is present in the database but never
 121        'directly' used. A dangling commit could be a root node.
 122
 123warning: git-fsck: tree <tree> has full pathnames in it::
 124        And it shouldn't...
 125
 126sha1 mismatch <object>::
 127        The database has an object who's sha1 doesn't match the
 128        database value.
 129        This indicates a serious data integrity problem.
 130
 131Environment Variables
 132---------------------
 133
 134GIT_OBJECT_DIRECTORY::
 135        used to specify the object database root (usually $GIT_DIR/objects)
 136
 137GIT_INDEX_FILE::
 138        used to specify the index file of the index
 139
 140GIT_ALTERNATE_OBJECT_DIRECTORIES::
 141        used to specify additional object database roots (usually unset)
 142
 143Author
 144------
 145Written by Linus Torvalds <torvalds@osdl.org>
 146
 147Documentation
 148--------------
 149Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
 150
 151GIT
 152---
 153Part of the gitlink:git[7] suite