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] [<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 tags, commits and tree objects. By avoiding to unpack blobs, this speeds up the operation, at the expense of missing corrupt objects or other problematic issues.

       --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.

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
       expect dangling commits - potential heads - due to lack of head information
           You haven’t specified any nodes as heads so it won’t be possible to differentiate between un-parented commits and root nodes.

       missing sha1 directory <dir>
           The directory holding the sha1 objects is missing.

       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.

       sha1 mismatch <object>
           The database has an object who’s sha1 doesn’t match the 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

Git 2.20.1                                                                                        04/20/2020                                                                                      GIT-FSCK(1)