NAME

       git-fsck - Verifies the connectivity and validity of the objects in the database

SYNOPSIS

       git fsck [--tags] [--root] [--unreachable] [--cache] [--no-reflogs]
                [--[no-]full] [--strict] [--verbose] [--lost-found]
                [--[no-]dangling] [--[no-]progress] [--connectivity-only]
                [--[no-]name-objects] [<object>...]

DESCRIPTION

       Verifies the connectivity and validity of the objects in the database.

OPTIONS

       <object>
           An object to treat as the head of an unreachability trace.

           If no objects are given, git fsck defaults to using the index file, all SHA-1
           references in refs namespace, and all reflogs (unless --no-reflogs is given) as heads.

       --unreachable
           Print out objects that exist but that aren’t reachable from any of the reference
           nodes.

       --[no-]dangling
           Print objects that exist but that are never directly used (default).  --no-dangling
           can be used to omit this information from the output.

       --root
           Report root nodes.

       --tags
           Report tags.

       --cache
           Consider any object recorded in the index also as a head node for an unreachability
           trace.

       --no-reflogs
           Do not consider commits that are referenced only by an entry in a reflog to be
           reachable. This option is meant only to search for commits that used to be in a ref,
           but now aren’t, but are still in that corresponding reflog.

       --full
           Check not just objects in GIT_OBJECT_DIRECTORY ($GIT_DIR/objects), but also the ones
           found in alternate object pools listed in GIT_ALTERNATE_OBJECT_DIRECTORIES or
           $GIT_DIR/objects/info/alternates, and in packed Git archives found in
           $GIT_DIR/objects/pack and corresponding pack subdirectories in alternate object pools.
           This is now default; you can turn it off with --no-full.

       --connectivity-only
           Check only the connectivity of reachable objects, making sure that any objects
           referenced by a reachable tag, commit, or tree is present. This speeds up the
           operation by avoiding reading blobs entirely (though it does still check that
           referenced blobs exist). This will detect corruption in commits and trees, but not do
           any semantic checks (e.g., for format errors). Corruption in blob objects will not be
           detected at all.

           Unreachable tags, commits, and trees will also be accessed to find the tips of
           dangling segments of history. Use --no-dangling if you don’t care about this output
           and want to speed it up further.

       --strict
           Enable more strict checking, namely to catch a file mode recorded with g+w bit set,
           which was created by older versions of Git. Existing repositories, including the Linux
           kernel, Git itself, and sparse repository have old objects that triggers this check,
           but it is recommended to check new projects with this flag.

       --verbose
           Be chatty.

       --lost-found
           Write dangling objects into .git/lost-found/commit/ or .git/lost-found/other/,
           depending on type. If the object is a blob, the contents are written into the file,
           rather than its object name.

       --name-objects
           When displaying names of reachable objects, in addition to the SHA-1 also display a
           name that describes how they are reachable, compatible with git-rev-parse(1), e.g.
           HEAD@{1234567890}~25^2:src/.

       --[no-]progress
           Progress status is reported on the standard error stream by default when it is
           attached to a terminal, unless --no-progress or --verbose is specified. --progress
           forces progress status even if the standard error stream is not directed to a
           terminal.

CONFIGURATION

       fsck.<msg-id>
           During fsck git may find issues with legacy data which wouldn’t be generated by
           current versions of git, and which wouldn’t be sent over the wire if
           transfer.fsckObjects was set. This feature is intended to support working with legacy
           repositories containing such data.

           Setting fsck.<msg-id> will be picked up by git-fsck(1), but to accept pushes of such
           data set receive.fsck.<msg-id> instead, or to clone or fetch it set
           fetch.fsck.<msg-id>.

           The rest of the documentation discusses fsck.*  for brevity, but the same applies for
           the corresponding receive.fsck.*  and fetch.<msg-id>.*. variables.

           Unlike variables like color.ui and core.editor the receive.fsck.<msg-id> and
           fetch.fsck.<msg-id> variables will not fall back on the fsck.<msg-id> configuration if
           they aren’t set. To uniformly configure the same fsck settings in different
           circumstances all three of them they must all set to the same values.

           When fsck.<msg-id> is set, errors can be switched to warnings and vice versa by
           configuring the fsck.<msg-id> setting where the <msg-id> is the fsck message ID and
           the value is one of error, warn or ignore. For convenience, fsck prefixes the
           error/warning with the message ID, e.g. "missingEmail: invalid author/committer line -
           missing email" means that setting fsck.missingEmail = ignore will hide that issue.

           In general, it is better to enumerate existing objects with problems with
           fsck.skipList, instead of listing the kind of breakages these problematic objects
           share to be ignored, as doing the latter will allow new instances of the same
           breakages go unnoticed.

           Setting an unknown fsck.<msg-id> value will cause fsck to die, but doing the same for
           receive.fsck.<msg-id> and fetch.fsck.<msg-id> will only cause git to warn.

       fsck.skipList
           The path to a list of object names (i.e. one unabbreviated SHA-1 per line) that are
           known to be broken in a non-fatal way and should be ignored. On versions of Git 2.20
           and later comments (#), empty lines, and any leading and trailing whitespace is
           ignored. Everything but a SHA-1 per line will error out on older versions.

           This feature is useful when an established project should be accepted despite early
           commits containing errors that can be safely ignored such as invalid committer email
           addresses. Note: corrupt objects cannot be skipped with this setting.

           Like fsck.<msg-id> this variable has corresponding receive.fsck.skipList and
           fetch.fsck.skipList variants.

           Unlike variables like color.ui and core.editor the receive.fsck.skipList and
           fetch.fsck.skipList variables will not fall back on the fsck.skipList configuration if
           they aren’t set. To uniformly configure the same fsck settings in different
           circumstances all three of them they must all set to the same values.

           Older versions of Git (before 2.20) documented that the object names list should be
           sorted. This was never a requirement, the object names could appear in any order, but
           when reading the list we tracked whether the list was sorted for the purposes of an
           internal binary search implementation, which could save itself some work with an
           already sorted list. Unless you had a humongous list there was no reason to go out of
           your way to pre-sort the list. After Git version 2.20 a hash implementation is used
           instead, so there’s now no reason to pre-sort the list.

DISCUSSION

       git-fsck tests SHA-1 and general object sanity, and it does full tracking of the resulting
       reachability and everything else. It prints out any corruption it finds (missing or bad
       objects), and if you use the --unreachable flag it will also print out objects that exist
       but that aren’t reachable from any of the specified head nodes (or the default set, as
       mentioned above).

       Any corrupt objects you will have to find in backups or other archives (i.e., you can just
       remove them and do an rsync with some other site in the hopes that somebody else has the
       object you have corrupted).

       If core.commitGraph is true, the commit-graph file will also be inspected using git
       commit-graph verify. See git-commit-graph(1).

EXTRACTED DIAGNOSTICS

       unreachable <type> <object>
           The <type> object <object>, isn’t actually referred to directly or indirectly in any
           of the trees or commits seen. This can mean that there’s another root node that you’re
           not specifying or that the tree is corrupt. If you haven’t missed a root node then you
           might as well delete unreachable nodes since they can’t be used.

       missing <type> <object>
           The <type> object <object>, is referred to but isn’t present in the database.

       dangling <type> <object>
           The <type> object <object>, is present in the database but never directly used. A
           dangling commit could be a root node.

       hash mismatch <object>
           The database has an object whose hash doesn’t match the object database value. This
           indicates a serious data integrity problem.

ENVIRONMENT VARIABLES

       GIT_OBJECT_DIRECTORY
           used to specify the object database root (usually $GIT_DIR/objects)

       GIT_INDEX_FILE
           used to specify the index file of the index

       GIT_ALTERNATE_OBJECT_DIRECTORIES
           used to specify additional object database roots (usually unset)

GIT

       Part of the git(1) suite