git/Documentation/git.txt
Junio C Hamano f9253394a2 [PATCH] Add git-verify-pack command.
Given a list of <pack>.idx files, this command validates the
index file and the corresponding .pack file for consistency.

This patch also uses the same validation mechanism in fsck-cache
when the --full flag is used.

During normal operation, sha1_file.c verifies that a given .idx
file matches the .pack file by comparing the SHA1 checksum
stored in .idx file and .pack file as a minimum sanity check.
We may further want to check the pack signature and version when
we map the pack, but that would be a separate patch.

Earlier, errors to map a pack file was not flagged fatal but led
to a random fatal error later.  This version explicitly die()s
when such an error is detected.

Signed-off-by: Junio C Hamano <junkio@cox.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-06-29 09:11:39 -07:00

309 lines
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git(7)
======
May 2005
NAME
----
git - the stupid content tracker
SYNOPSIS
--------
'git-<command>' <args>
DESCRIPTION
-----------
This is reference information for the core git commands.
The Discussion section below contains much useful definition and
clarification info - read that first. And of the commands, I suggest
reading link:git-update-cache.html[git-update-cache] and
link:git-read-tree.html[git-read-tree] first - I wish I had!
David Greaves <david@dgreaves.com>
08/05/05
Updated by Junio C Hamano <junkio@cox.net> on 2005-05-05 to
reflect recent changes.
Commands Overview
-----------------
The git commands can helpfully be split into those that manipulate
the repository, the cache and the working fileset and those that
interrogate and compare them.
There are also some ancilliary 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
~~~~~~~~~~~~~~~~~~~~~
link:git-checkout-cache.html[git-checkout-cache]::
Copy files from the cache to the working directory
link:git-commit-tree.html[git-commit-tree]::
Creates a new commit object
link:git-init-db.html[git-init-db]::
Creates an empty git object database
link:git-merge-base.html[git-merge-base]::
Finds as good a common ancestor as possible for a merge
link:git-mktag.html[git-mktag]::
Creates a tag object
link:git-read-tree.html[git-read-tree]::
Reads tree information into the directory cache
link:git-update-cache.html[git-update-cache]::
Modifies the index or directory cache
link:git-write-blob.html[git-write-blob]::
Creates a blob from a file
link:git-write-tree.html[git-write-tree]::
Creates a tree from the current cache
Interrogation commands
~~~~~~~~~~~~~~~~~~~~~~
link:git-cat-file.html[git-cat-file]::
Provide content or type information for repository objects
link:git-check-files.html[git-check-files]::
Verify a list of files are up-to-date
link:git-diff-cache.html[git-diff-cache]::
Compares content and mode of blobs between the cache and repository
link:git-diff-files.html[git-diff-files]::
Compares files in the working tree and the cache
link:git-diff-tree.html[git-diff-tree]::
Compares the content and mode of blobs found via two tree objects
link:git-export.html[git-export]::
Exports each commit and a diff against each of its parents
link:git-fsck-cache.html[git-fsck-cache]::
Verifies the connectivity and validity of the objects in the database
link:git-ls-files.html[git-ls-files]::
Information about files in the cache/working directory
link:git-ls-tree.html[git-ls-tree]::
Displays a tree object in human readable form
link:git-merge-cache.html[git-merge-cache]::
Runs a merge for files needing merging
link:git-rev-list.html[git-rev-list]::
Lists commit objects in reverse chronological order
link:git-rev-tree.html[git-rev-tree]::
Provides the revision tree for one or more commits
link:git-tar-tree.html[git-tar-tree]::
Creates a tar archive of the files in the named tree
link:git-unpack-file.html[git-unpack-file]::
Creates a temporary file with a blob's contents
link:git-verify-pack.html[git-verify-pack]::
Validates packed GIT archive files
The interrogate commands may create files - and you can force them to
touch the working file set - but in general they don't
Ancilliary Commands
-------------------
Manipulators:
link:git-apply-patch-script.html[git-apply-patch-script]::
Sample script to apply the diffs from git-diff-*
link:git-convert-cache.html[git-convert-cache]::
Converts old-style GIT repository
link:git-http-pull.html[git-http-pull]::
Downloads a remote GIT repository via HTTP
link:git-local-pull.html[git-local-pull]::
Duplicates another GIT repository on a local system
link:git-merge-one-file-script.html[git-merge-one-file-script]::
The standard helper program to use with "git-merge-cache"
link:git-pull-script.html[git-pull-script]::
Script used by Linus to pull and merge a remote repository
link:git-prune-script.html[git-prune-script]::
Prunes all unreachable objects from the object database
link:git-resolve-script.html[git-resolve-script]::
Script used to merge two trees
link:git-tag-script.html[git-tag-script]::
An example script to create a tag object signed with GPG
link:git-ssh-pull.html[git-ssh-pull]::
Pulls from a remote repository over ssh connection
Interogators:
link:git-diff-helper.html[git-diff-helper]::
Generates patch format output for git-diff-*
link:git-ssh-push.html[git-ssh-push]::
Helper "server-side" program used by git-ssh-pull
Identifier Terminology
----------------------
<object>::
Indicates the sha1 identifier for any type of object
<blob>::
Indicates a blob object sha1 identifier
<tree>::
Indicates a tree object sha1 identifier
<commit>::
Indicates a commit object sha1 identifier
<tree-ish>::
Indicates a tree, commit or tag object sha1 identifier. 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/tag
<file>::
Indicates a filename - always relative to the root of
the tree structure GIT_INDEX_FILE describes.
Symbolic Identifiers
--------------------
Any git comand accepting any <object> can also use the following
symbolic notation:
HEAD::
indicates the head of the repository (ie the contents of
`$GIT_DIR/HEAD`)
<tag>::
a valid tag 'name'+
(ie the contents of `$GIT_DIR/refs/tags/<tag>`)
<head>::
a valid head 'name'+
(ie the contents of `$GIT_DIR/refs/heads/<head>`)
<snap>::
a valid snapshot 'name'+
(ie the contents of `$GIT_DIR/refs/snap/<snap>`)
File/Directory Structure
------------------------
The git-core manipulates the following areas in the directory:
.git/ The base (overridden with $GIT_DIR)
objects/ The object base (overridden with $GIT_OBJECT_DIRECTORY)
??/ 'First 2 chars of object' directories
It can interrogate (but never updates) the following areas:
refs/ Directories containing symbolic names for objects
(each file contains the hex SHA1 + newline)
heads/ Commits which are heads of various sorts
tags/ Tags, by the tag name (or some local renaming of it)
snap/ ????
... Everything else isn't shared
HEAD Symlink to refs/heads/<something>
Higher level SCMs may provide and manage additional information in the
GIT_DIR.
Terminology
-----------
Each line contains terms which you may see used interchangeably
object database, .git directory
directory cache, index
id, sha1, sha1-id, sha1 hash
type, tag
Environment Variables
---------------------
Various git commands use the following environment variables:
The git Repository
~~~~~~~~~~~~~~~~~~
These environment variables apply to 'all' core git commands. Nb: it
is worth noting that they may be used/overridden by SCMS sitting above
git so take care if using Cogito etc
'GIT_INDEX_FILE'::
This environment allows the specification of an alternate
cache/index file. If not specified, the default of
`$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 ":" seperated 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 `./.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 link:git-commit-tree.html[git-commit-tree]
git Diffs
~~~~~~~~~
'GIT_DIFF_OPTS'::
'GIT_EXTERNAL_DIFF'::
see the "generating patches" section in :
link:git-diff-cache.html[git-diff-cache];
link:git-diff-files.html[git-diff-files];
link:git-diff-tree.html[git-diff-tree]
Discussion
----------
include::../README[]
Author
------
Written by Linus Torvalds <torvalds@osdl.org> and the git-list <git@vger.kernel.org>.
Documentation
--------------
Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.
GIT
---
Part of the link:git.html[git] suite