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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CONFIGURATION | DISCUSSION | EXTRACTED DIAGNOSTICS | FSCK MESSAGES | ENVIRONMENT VARIABLES | GIT | NOTES | COLOPHON |
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GIT-FSCK(1) Git Manual GIT-FSCK(1)
git-fsck - Verifies the connectivity and validity of the objects
in the database
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>...]
Verifies the connectivity and validity of the objects in the
database.
<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.
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.
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).
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.
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.
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)
Part of the git(1) suite
1. git@vger.kernel.org
mailto:git@vger.kernel.org
This page is part of the git (Git distributed version control
system) project. Information about the project can be found at
⟨http://git-scm.com/⟩. If you have a bug report for this manual
page, see ⟨http://git-scm.com/community⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/git/git.git⟩ on 2025-08-11. (At that time,
the date of the most recent commit that was found in the
repository was 2025-08-07.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Git 2.51.0.rc1 2025-08-07 GIT-FSCK(1)
Pages that refer to this page: git(1), git-config(1), git-fetch(1), git-fsck(1), git-fsck-objects(1), git-index-pack(1), git-mktag(1), git-prune(1), git-refs(1)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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