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git-gc(1)
=========
 
NAME
----
git-gc - Cleanup unnecessary files and optimize the local repository
 
 
SYNOPSIS
--------
[verse]
'git gc' [--aggressive] [--auto] [--quiet] [--prune=<date> | --no-prune] [--force] [--keep-largest-pack]
 
DESCRIPTION
-----------
Runs a number of housekeeping tasks within the current repository,
such as compressing file revisions (to reduce disk space and increase
performance), removing unreachable objects which may have been
created from prior invocations of 'git add', packing refs, pruning
reflog, rerere metadata or stale working trees. May also update ancillary
indexes such as the commit-graph.
 
When common porcelain operations that create objects are run, they
will check whether the repository has grown substantially since the
last maintenance, and if so run `git gc` automatically. See `gc.auto`
below for how to disable this behavior.
 
Running `git gc` manually should only be needed when adding objects to
a repository without regularly running such porcelain commands, to do
a one-off repository optimization, or e.g. to clean up a suboptimal
mass-import. See the "PACKFILE OPTIMIZATION" section in
linkgit:git-fast-import[1] for more details on the import case.
 
OPTIONS
-------
 
--aggressive::
	Usually 'git gc' runs very quickly while providing good disk
	space utilization and performance.  This option will cause
	'git gc' to more aggressively optimize the repository at the expense
	of taking much more time.  The effects of this optimization are
	persistent, so this option only needs to be used occasionally; every
	few hundred changesets or so.
 
--auto::
	With this option, 'git gc' checks whether any housekeeping is
	required; if not, it exits without performing any work.
+
See the `gc.auto` option in the "CONFIGURATION" section below for how
this heuristic works.
+
Once housekeeping is triggered by exceeding the limits of
configuration options such as `gc.auto` and `gc.autoPackLimit`, all
other housekeeping tasks (e.g. rerere, working trees, reflog...) will
be performed as well.
 
 
--prune=<date>::
	Prune loose objects older than date (default is 2 weeks ago,
	overridable by the config variable `gc.pruneExpire`).
	--prune=now prunes loose objects regardless of their age and
	increases the risk of corruption if another process is writing to
	the repository concurrently; see "NOTES" below. --prune is on by
	default.
 
--no-prune::
	Do not prune any loose objects.
 
--quiet::
	Suppress all progress reports.
 
--force::
	Force `git gc` to run even if there may be another `git gc`
	instance running on this repository.
 
--keep-largest-pack::
	All packs except the largest pack and those marked with a
	`.keep` files are consolidated into a single pack. When this
	option is used, `gc.bigPackThreshold` is ignored.
 
CONFIGURATION
-------------
 
The below documentation is the same as what's found in
linkgit:git-config[1]:
 
include::config/gc.txt[]
 
NOTES
-----
 
'git gc' tries very hard not to delete objects that are referenced
anywhere in your repository. In
particular, it will keep not only objects referenced by your current set
of branches and tags, but also objects referenced by the index,
remote-tracking branches, refs saved by 'git filter-branch' in
refs/original/, or reflogs (which may reference commits in branches
that were later amended or rewound).
If you are expecting some objects to be deleted and they aren't, check
all of those locations and decide whether it makes sense in your case to
remove those references.
 
On the other hand, when 'git gc' runs concurrently with another process,
there is a risk of it deleting an object that the other process is using
but hasn't created a reference to. This may just cause the other process
to fail or may corrupt the repository if the other process later adds a
reference to the deleted object. Git has two features that significantly
mitigate this problem:
 
. Any object with modification time newer than the `--prune` date is kept,
  along with everything reachable from it.
 
. Most operations that add an object to the database update the
  modification time of the object if it is already present so that #1
  applies.
 
However, these features fall short of a complete solution, so users who
run commands concurrently have to live with some risk of corruption (which
seems to be low in practice) unless they turn off automatic garbage
collection with 'git config gc.auto 0'.
 
HOOKS
-----
 
The 'git gc --auto' command will run the 'pre-auto-gc' hook.  See
linkgit:githooks[5] for more information.
 
 
SEE ALSO
--------
linkgit:git-prune[1]
linkgit:git-reflog[1]
linkgit:git-repack[1]
linkgit:git-rerere[1]
 
GIT
---
Part of the linkgit:git[1] suite