path: root/Documentation/git.txt

git(7)
======

NAME
----
git - the stupid content tracker


SYNOPSIS
--------
'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [--help] COMMAND [ARGS]

DESCRIPTION
-----------
'git' is both a program and a directory content tracker system.
The program 'git' is just a wrapper to reach the core git programs
(or a potty if you like, as it's not exactly porcelain but still
brings your stuff to the plumbing).

OPTIONS
-------
--version::
	prints the git suite version that the 'git' program came from.

--help::
	prints the synopsis and a list of available commands.
	If a git command is named this option will bring up the
	man-page for that command.

--exec-path::
	path to wherever your core git programs are installed.
	This can also be controlled by setting the GIT_EXEC_PATH
	environment variable. If no path is given 'git' will print
	the current setting and then exit.


NOT LEARNING CORE GIT COMMANDS
------------------------------

This manual is intended to give complete background information
and internal workings of git, which may be too much for most
people.  The <<Discussion>> section below contains much useful
definition and clarification - read that first.

If you are interested in using git to manage (version control)
projects, use link:everyday.html[Everyday GIT] as a guide to the
minimum set of commands you need to know for day-to-day work.
Most likely, that will get you started, and you can go a long
way without knowing the low level details too much.

The link:tutorial.html[tutorial] document covers how things
internally work.

If you are migrating from CVS, link:cvs-migration.html[cvs
migration] document may be helpful after you finish the
tutorial.

After you get the general feel from the tutorial and this
overview page, you may want to take a look at the
link:howto-index.html[howto] documents.


CORE GIT COMMANDS
-----------------

If you are writing your own Porcelain, you need to be familiar
with most of the low level commands --- I suggest starting from
gitlink:git-update-index[1] and gitlink:git-read-tree[1].


Commands Overview
-----------------
The git commands can helpfully be split into those that manipulate
the repository, the index and the files in the working tree, those that
interrogate and compare them, and those that moves objects and
references between repositories.

In addition, git itself comes with a spartan set of porcelain
commands.  They are usable but are not meant to compete with real
Porcelains.

There are also some ancillary programs that can be viewed as useful
aids for using the core commands but which are unlikely to be used by
SCMs layered over git.

Manipulation commands
~~~~~~~~~~~~~~~~~~~~~
gitlink:git-apply[1]::
	Reads a "diff -up1" or git generated patch file and
	applies it to the working tree.

gitlink:git-checkout-index[1]::
	Copy files from the index to the working tree.

gitlink:git-commit-tree[1]::
	Creates a new commit object.

gitlink:git-hash-object[1]::
	Computes the object ID from a file.

gitlink:git-index-pack[1]::
	Build pack idx file for an existing packed archive.

gitlink:git-init-db[1]::
	Creates an empty git object database, or reinitialize an
	existing one.

gitlink:git-merge-index[1]::
	Runs a merge for files needing merging.

gitlink:git-mktag[1]::
	Creates a tag object.

gitlink:git-pack-objects[1]::
	Creates a packed archive of objects.

gitlink:git-prune-packed[1]::
	Remove extra objects that are already in pack files.

gitlink:git-read-tree[1]::
	Reads tree information into the index.

gitlink:git-repo-config[1]::
	Get and set options in .git/config.

gitlink:git-unpack-objects[1]::
	Unpacks objects out of a packed archive.

gitlink:git-update-index[1]::
	Registers files in the working tree to the index.

gitlink:git-write-tree[1]::
	Creates a tree from the index.


Interrogation commands
~~~~~~~~~~~~~~~~~~~~~~

gitlink:git-cat-file[1]::
	Provide content or type/size information for repository objects.

gitlink:git-diff-index[1]::
	Compares content and mode of blobs between the index and repository.

gitlink:git-diff-files[1]::
	Compares files in the working tree and the index.

gitlink:git-diff-stages[1]::
	Compares two "merge stages" in the index.

gitlink:git-diff-tree[1]::
	Compares the content and mode of blobs found via two tree objects.

gitlink:git-fsck-objects[1]::
	Verifies the connectivity and validity of the objects in the database.

gitlink:git-ls-files[1]::
	Information about files in the index and the working tree.

gitlink:git-ls-tree[1]::
	Displays a tree object in human readable form.

gitlink:git-merge-base[1]::
	Finds as good common ancestors as possible for a merge.

gitlink:git-name-rev[1]::
	Find symbolic names for given revs.

gitlink:git-pack-redundant[1]::
	Find redundant pack files.

gitlink:git-rev-list[1]::
	Lists commit objects in reverse chronological order.

gitlink:git-show-index[1]::
	Displays contents of a pack idx file.

gitlink:git-tar-tree[1]::
	Creates a tar archive of the files in the named tree object.

gitlink:git-unpack-file[1]::
	Creates a temporary file with a blob's contents.

gitlink:git-var[1]::
	Displays a git logical variable.

gitlink:git-verify-pack[1]::
	Validates packed git archive files.

In general, the interrogate commands do not touch the files in
the working tree.


Synching repositories
~~~~~~~~~~~~~~~~~~~~~

gitlink:git-clone-pack[1]::
	Clones a repository into the current repository (engine
	for ssh and local transport).

gitlink:git-fetch-pack[1]::
	Updates from a remote repository (engine for ssh and
	local transport).

gitlink:git-http-fetch[1]::
	Downloads a remote git repository via HTTP by walking
	commit chain.

gitlink:git-local-fetch[1]::
	Duplicates another git repository on a local system by
	walking commit chain.

gitlink:git-peek-remote[1]::
	Lists references on a remote repository using
	upload-pack protocol (engine for ssh and local
	transport).

gitlink:git-receive-pack[1]::
	Invoked by 'git-send-pack' to receive what is pushed to it.

gitlink:git-send-pack[1]::
	Pushes to a remote repository, intelligently.

gitlink:git-http-push[1]::
	Push missing objects using HTTP/DAV.

gitlink:git-shell[1]::
	Restricted shell for GIT-only SSH access.

gitlink:git-ssh-fetch[1]::
	Pulls from a remote repository over ssh connection by
	walking commit chain.

gitlink:git-ssh-upload[1]::
	Helper "server-side" program used by git-ssh-fetch.

gitlink:git-update-server-info[1]::
	Updates auxiliary information on a dumb server to help
	clients discover references and packs on it.

gitlink:git-upload-pack[1]::
	Invoked by 'git-clone-pack' and 'git-fetch-pack' to push
	what are asked for.


Porcelain-ish Commands
----------------------

gitlink:git-add[1]::
	Add paths to the index.

gitlink:git-am[1]::
	Apply patches from a mailbox, but cooler.

gitlink:git-applymbox[1]::
	Apply patches from a mailbox, original version by Linus.

gitlink:git-bisect[1]::
	Find the change that introduced a bug by binary search.

gitlink:git-branch[1]::
	Create and Show branches.

gitlink:git-checkout[1]::
	Checkout and switch to a branch.

gitlink:git-cherry-pick[1]::
	Cherry-pick the effect of an existing commit.

gitlink:git-clone[1]::
	Clones a repository into a new directory.

gitlink:git-commit[1]::
	Record changes to the repository.

gitlink:git-diff[1]::
	Show changes between commits, commit and working tree, etc.

gitlink:git-fetch[1]::
	Download from a remote repository via various protocols.

gitlink:git-format-patch[1]::
	Prepare patches for e-mail submission.

gitlink:git-grep[1]::
	Print lines matching a pattern.

gitlink:git-log[1]::
	Shows commit logs.

gitlink:git-ls-remote[1]::
	Shows references in a remote or local repository.

gitlink:git-merge[1]::
	Grand unified merge driver.

gitlink:git-mv[1]::
	Move or rename a file, a directory, or a symlink.

gitlink:git-pull[1]::
	Fetch from and merge with a remote repository.

gitlink:git-push[1]::
	Update remote refs along with associated objects.

gitlink:git-rebase[1]::
	Rebase local commits to the updated upstream head.

gitlink:git-repack[1]::
	Pack unpacked objects in a repository.

gitlink:git-reset[1]::
	Reset current HEAD to the specified state.

gitlink:git-resolve[1]::
	Merge two commits.

gitlink:git-revert[1]::
	Revert an existing commit.

gitlink:git-shortlog[1]::
	Summarizes 'git log' output.

gitlink:git-show-branch[1]::
	Show branches and their commits.

gitlink:git-status[1]::
	Shows the working tree status.

gitlink:git-verify-tag[1]::
	Check the GPG signature of tag.

gitlink:git-whatchanged[1]::
	Shows commit logs and differences they introduce.


Ancillary Commands
------------------
Manipulators:

gitlink:git-applypatch[1]::
	Apply one patch extracted from an e-mail.

gitlink:git-archimport[1]::
	Import an arch repository into git.

gitlink:git-convert-objects[1]::
	Converts old-style git repository.

gitlink:git-cvsimport[1]::
	Salvage your data out of another SCM people love to hate.

gitlink:git-cvsexportcommit[1]::
	Export a single commit to a CVS checkout.

gitlink:git-lost-found[1]::
	Recover lost refs that luckily have not yet been pruned.

gitlink:git-merge-one-file[1]::
	The standard helper program to use with `git-merge-index`.

gitlink:git-prune[1]::
	Prunes all unreachable objects from the object database.

gitlink:git-relink[1]::
	Hardlink common objects in local repositories.

gitlink:git-svnimport[1]::
	Import a SVN repository into git.

gitlink:git-sh-setup[1]::
	Common git shell script setup code.

gitlink:git-symbolic-ref[1]::
	Read and modify symbolic refs.

gitlink:git-tag[1]::
	An example script to create a tag object signed with GPG.

gitlink:git-update-ref[1]::
	Update the object name stored in a ref safely.


Interrogators:

gitlink:git-check-ref-format[1]::
	Make sure ref name is well formed.

gitlink:git-cherry[1]::
	Find commits not merged upstream.

gitlink:git-count-objects[1]::
	Count unpacked number of objects and their disk consumption.

gitlink:git-daemon[1]::
	A really simple server for git repositories.

gitlink:git-get-tar-commit-id[1]::
	Extract commit ID from an archive created using git-tar-tree.

gitlink:git-mailinfo[1]::
	Extracts patch and authorship information from a single
	e-mail message, optionally transliterating the commit
	message into utf-8.

gitlink:git-mailsplit[1]::
	A stupid program to split UNIX mbox format mailbox into
	individual pieces of e-mail.

gitlink:git-patch-id[1]::
	Compute unique ID for a patch.

gitlink:git-parse-remote[1]::
	Routines to help parsing `$GIT_DIR/remotes/` files.

gitlink:git-request-pull[1]::
	git-request-pull.

gitlink:git-rev-parse[1]::
	Pick out and massage parameters.

gitlink:git-send-email[1]::
	Send patch e-mails out of "format-patch --mbox" output.

gitlink:git-symbolic-ref[1]::
	Read and modify symbolic refs.

gitlink:git-stripspace[1]::
	Filter out empty lines.


Commands not yet documented
---------------------------

gitlink:gitk[1]::
	The gitk repository browser.


Configuration Mechanism
-----------------------

Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
is used to hold per-repository configuration options.  It is a
simple text file modelled after `.ini` format familiar to some
people.  Here is an example:

------------
#
# A '#' or ';' character indicates a comment.
#

; core variables
[core]
	; Don't trust file modes
	filemode = false

; user identity
[user]
	name = "Junio C Hamano"
	email = "junkio@twinsun.com"

------------

Various commands read from the configuration file and adjust
their operation accordingly.


Identifier Terminology
----------------------
<object>::
	Indicates the object name for any type of object.

<blob>::
	Indicates a blob object name.

<tree>::
	Indicates a tree object name.

<commit>::
	Indicates a commit object name.

<tree-ish>::
	Indicates a tree, commit or tag object name.  A
	command that takes a <tree-ish> argument ultimately wants to
	operate on a <tree> object but automatically dereferences
	<commit> and <tag> objects that point at a <tree>.

<type>::
	Indicates that an object type is required.
	Currently one of: `blob`, `tree`, `commit`, or `tag`.

<file>::
	Indicates a filename - almost always relative to the
	root of the tree structure `GIT_INDEX_FILE` describes.

Symbolic Identifiers
--------------------
Any git command accepting any <object> can also use the following
symbolic notation:

HEAD::
	indicates the head of the current branch (i.e. the
	contents of `$GIT_DIR/HEAD`).

<tag>::
	a valid tag 'name'
	(i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).

<head>::
	a valid head 'name'
	(i.e. the contents of `$GIT_DIR/refs/heads/<head>`).

<snap>::
	a valid snapshot 'name'
	(i.e. the contents of `$GIT_DIR/refs/snap/<snap>`).


File/Directory Structure
------------------------

Please see link:repository-layout.html[repository layout] document.

Higher level SCMs may provide and manage additional information in the
`$GIT_DIR`.


Terminology
-----------
Please see link:glossary.html[glossary] document.


Environment Variables
---------------------
Various git commands use the following environment variables:

The git Repository
~~~~~~~~~~~~~~~~~~
These environment variables apply to 'all' core git commands. Nb: it
is worth noting that they may be used/overridden by SCMS sitting above
git so take care if using Cogito etc.

'GIT_INDEX_FILE'::
	This environment allows the specification of an alternate
	index file. If not specified, the default of `$GIT_DIR/index`
	is used.

'GIT_OBJECT_DIRECTORY'::
	If the object storage directory is specified via this
	environment variable then the sha1 directories are created
	underneath - otherwise the default `$GIT_DIR/objects`
	directory is used.

'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
	Due to the immutable nature of git objects, old objects can be
	archived into shared, read-only directories. This variable
	specifies a ":" separated list of git object directories which
	can be used to search for git objects. New objects will not be
	written to these directories.

'GIT_DIR'::
	If the 'GIT_DIR' environment variable is set then it
	specifies a path to use instead of the default `.git`
	for the base of the repository.

git Commits
~~~~~~~~~~~
'GIT_AUTHOR_NAME'::
'GIT_AUTHOR_EMAIL'::
'GIT_AUTHOR_DATE'::
'GIT_COMMITTER_NAME'::
'GIT_COMMITTER_EMAIL'::
	see gitlink:git-commit-tree[1]

git Diffs
~~~~~~~~~
'GIT_DIFF_OPTS'::
'GIT_EXTERNAL_DIFF'::
	see the "generating patches" section in :
	gitlink:git-diff-index[1];
	gitlink:git-diff-files[1];
	gitlink:git-diff-tree[1]

Discussion[[Discussion]]
------------------------
include::../README[]

Authors
-------
* git's founding father is Linus Torvalds <torvalds@osdl.org>.
* The current git nurse is Junio C Hamano <junkio@cox.net>.
* The git potty was written by Andres Ericsson <ae@op5.se>.
* General upbringing is handled by the git-list <git@vger.kernel.org>.

Documentation
--------------
The documentation for git suite was started by David Greaves
<david@dgreaves.com>, and later enhanced greatly by the
contributors on the git-list <git@vger.kernel.org>.

GIT
---
Part of the gitlink:git[7] suite