GIT-FSCK(1)			  Git Manual			   GIT-FSCK(1)

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] [--[no-]references] [<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 the 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 are
	   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 trigger 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.

       --[no-]references
	   Control whether to check the references database consistency via
	   git refs verify. See git-refs(1) for details. The default is to
	   check the references database.

CONFIGURATION
       Everything below this line in this section is selectively included from
       the git-config(1) documentation. The content is the same as what’s
       found there:

       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.fsck.*.
	   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 must be 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.

	   See the Fsck Messages section of git-fsck(1) for supported values
	   of <msg-id>.

       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 are 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 must be 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.

FSCK MESSAGES
       The following lists the types of errors git fsck detects and what each
       error means, with their default severity. The severity of the error,
       other than those that are marked as "(FATAL)", can be tweaked by
       setting the corresponding fsck.<msg-id> configuration variable.

       badDate
	   (ERROR) Invalid date format in an author/committer line.

       badDateOverflow
	   (ERROR) Invalid date value in an author/committer line.

       badEmail
	   (ERROR) Invalid email format in an author/committer line.

       badFilemode
	   (INFO) A tree contains a bad filemode entry.

       badName
	   (ERROR) An author/committer name is empty.

       badObjectSha1
	   (ERROR) An object has a bad sha1.

       badPackedRefEntry
	   (ERROR) The "packed-refs" file contains an invalid entry.

       badPackedRefHeader
	   (ERROR) The "packed-refs" file contains an invalid header.

       badParentSha1
	   (ERROR) A commit object has a bad parent sha1.

       badRefContent
	   (ERROR) A ref has bad content.

       badRefFiletype
	   (ERROR) A ref has a bad file type.

       badRefName
	   (ERROR) A ref has an invalid format.

       badReferentName
	   (ERROR) The referent name of a symref is invalid.

       badTagName
	   (INFO) A tag has an invalid format.

       badTimezone
	   (ERROR) Found an invalid time zone in an author/committer line.

       badTree
	   (ERROR) A tree cannot be parsed.

       badTreeSha1
	   (ERROR) A tree has an invalid format.

       badType
	   (ERROR) Found an invalid object type.

       duplicateEntries
	   (ERROR) A tree contains duplicate file entries.

       emptyName
	   (WARN) A path contains an empty name.

       emptyPackedRefsFile
	   (INFO) "packed-refs" file is empty. Report to the
	   git@vger.kernel.org[1] mailing list if you see this error. As only
	   very early versions of Git would create such an empty "packed_refs"
	   file, we might tighten this rule in the future.

       extraHeaderEntry
	   (IGNORE) Extra headers found after tagger.

       fullPathname
	   (WARN) A path contains the full path starting with "/".

       gitattributesBlob
	   (ERROR) A non-blob found at .gitattributes.

       gitattributesLarge
	   (ERROR) The .gitattributes blob is too large.

       gitattributesLineLength
	   (ERROR) The .gitattributes blob contains too long lines.

       gitattributesMissing
	   (ERROR) Unable to read .gitattributes blob.

       gitattributesSymlink
	   (INFO) .gitattributes is a symlink.

       gitignoreSymlink
	   (INFO) .gitignore is a symlink.

       gitmodulesBlob
	   (ERROR) A non-blob found at .gitmodules.

       gitmodulesLarge
	   (ERROR) The .gitmodules file is too large to parse.

       gitmodulesMissing
	   (ERROR) Unable to read .gitmodules blob.

       gitmodulesName
	   (ERROR) A submodule name is invalid.

       gitmodulesParse
	   (INFO) Could not parse .gitmodules blob.

       gitmodulesLarge; (ERROR) .gitmodules blob is too large to parse.

       gitmodulesPath
	   (ERROR) .gitmodules path is invalid.

       gitmodulesSymlink
	   (ERROR) .gitmodules is a symlink.

       gitmodulesUpdate
	   (ERROR) Found an invalid submodule update setting.

       gitmodulesUrl
	   (ERROR) Found an invalid submodule url.

       hasDot
	   (WARN) A tree contains an entry named ..

       hasDotdot
	   (WARN) A tree contains an entry named ...

       hasDotgit
	   (WARN) A tree contains an entry named .git.

       largePathname
	   (WARN) A tree contains an entry with a very long path name. If the
	   value of fsck.largePathname contains a colon, that value is used as
	   the maximum allowable length (e.g., "warn:10" would complain about
	   any path component of 11 or more bytes). The default value is 4096.

       mailmapSymlink
	   (INFO) .mailmap is a symlink.

       missingAuthor
	   (ERROR) Author is missing.

       missingCommitter
	   (ERROR) Committer is missing.

       missingEmail
	   (ERROR) Email is missing in an author/committer line.

       missingNameBeforeEmail
	   (ERROR) Missing name before an email in an author/committer line.

       missingObject
	   (ERROR) Missing object line in tag object.

       missingSpaceBeforeDate
	   (ERROR) Missing space before date in an author/committer line.

       missingSpaceBeforeEmail
	   (ERROR) Missing space before the email in an author/committer line.

       missingTag
	   (ERROR) Unexpected end after type line in a tag object.

       missingTagEntry
	   (ERROR) Missing tag line in a tag object.

       missingTaggerEntry
	   (INFO) Missing tagger line in a tag object.

       missingTree
	   (ERROR) Missing tree line in a commit object.

       missingType
	   (ERROR) Invalid type value on the type line in a tag object.

       missingTypeEntry
	   (ERROR) Missing type line in a tag object.

       multipleAuthors
	   (ERROR) Multiple author lines found in a commit.

       nulInCommit
	   (WARN) Found a NUL byte in the commit object body.

       nulInHeader
	   (FATAL) NUL byte exists in the object header.

       nullSha1
	   (WARN) Tree contains entries pointing to a null sha1.

       packedRefEntryNotTerminated
	   (ERROR) The "packed-refs" file contains an entry that is not
	   terminated by a newline.

       packedRefUnsorted
	   (ERROR) The "packed-refs" file is not sorted.

       refMissingNewline
	   (INFO) A loose ref that does not end with newline(LF). As valid
	   implementations of Git never created such a loose ref file, it may
	   become an error in the future. Report to the git@vger.kernel.org[1]
	   mailing list if you see this error, as we need to know what tools
	   created such a file.

       symlinkRef
	   (INFO) A symbolic link is used as a symref. Report to the
	   git@vger.kernel.org[1] mailing list if you see this error, as we
	   are assessing the feasibility of dropping the support to drop
	   creating symbolic links as symrefs.

       symrefTargetIsNotARef
	   (INFO) The target of a symbolic reference points neither to a root
	   reference nor to a reference starting with "refs/". Although we
	   allow create a symref pointing to the referent which is outside the
	   "ref" by using git symbolic-ref, we may tighten the rule in the
	   future. Report to the git@vger.kernel.org[1] mailing list if you
	   see this error, as we need to know what tools created such a file.

       trailingRefContent
	   (INFO) A loose ref has trailing content. As valid implementations
	   of Git never created such a loose ref file, it may become an error
	   in the future. Report to the git@vger.kernel.org[1] mailing list if
	   you see this error, as we need to know what tools created such a
	   file.

       treeNotSorted
	   (ERROR) A tree is not properly sorted.

       unknownType
	   (ERROR) Found an unknown object type.

       unterminatedHeader
	   (FATAL) Missing end-of-line in the object header.

       zeroPaddedDate
	   (ERROR) Found a zero padded date in an author/committer line.

       zeroPaddedFilemode
	   (WARN) Found a zero padded filemode in a tree.

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

NOTES
	1. git@vger.kernel.org
	   mailto:git@vger.kernel.org

Git 2.51.0			  2025-08-17			   GIT-FSCK(1)