# git

## NAME



           git - the stupid content tracker
    


## SYNOPSIS



           _git_ [-v | --version] [-h | --help] [-C <path>] [-c <name>=<value>]
               [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
               [-p | --paginate | -P | --no-pager] [--no-replace-objects] [--no-lazy-fetch]
               [--no-optional-locks] [--no-advice] [--bare] [--git-dir=<path>]
               [--work-tree=<path>] [--namespace=<name>] [--config-env=<name>=<envvar>]
               <command> [<args>]
    


## DESCRIPTION



           Git is a fast, scalable, distributed revision control system with
           an unusually rich command set that provides both high-level
           operations and full access to internals.
    
           See gittutorial(7) to get started, then see giteveryday(7) for a
           useful minimum set of commands. The **Git User’s Manual******[1] has a
           more in-depth introduction.
    
           After you mastered the basic concepts, you can come back to this
           page to learn what commands Git offers. You can learn more about
           individual Git commands with "git help command".gitcli(7) manual
           page gives you an overview of the command-line command syntax.
    
           A formatted and hyperlinked copy of the latest Git documentation
           can be viewed at **https://git.github.io/htmldocs/git.html******or**https://git-scm.com/docs ******.


## OPTIONS



           -v, --version
               Prints the Git suite version that the _git_ program came from.
    
               This option is internally converted to **git version**... and
               accepts the same options as the git-version(1) command. If
               **--help** is also given, it takes precedence over **--version**.
    
           -h, --help
               Prints the synopsis and a list of the most commonly used
               commands. If the option **--all** or **-a** is given then all
               available commands are printed. If a Git command is named this
               option will bring up the manual page for that command.
    
               Other options are available to control how the manual page is
               displayed. See git-help(1) for more information, because **git**
               **--help**... is converted internally into **git help**....
    
           -C <path>
               Run as if git was started in _< path>_ instead of the current
               working directory. When multiple **-C** options are given, each
               subsequent non-absolute **-C** _< path>_ is interpreted relative to
               the preceding **-C** _< path>_. If _< path>_ is present but empty, e.g.
               **-C** "", then the current working directory is left unchanged.
    
               This option affects options that expect path name like
               **--git-dir** and **--work-tree** in that their interpretations of the
               path names would be made relative to the working directory
               caused by the **-C** option. For example the following invocations
               are equivalent:
    
                   git --git-dir=a.git --work-tree=b -C c status
                   git --git-dir=c/a.git --work-tree=c/b status
    
           -c <name>=<value>
               Pass a configuration parameter to the command. The value given
               will override values from configuration files. The <name> is
               expected in the same format as listed by _git config_ (subkeys
               separated by dots).
    
               Note that omitting the **=** in **git -c foo.bar**... is allowed and
               sets **foo.bar** to the boolean true value (just like [**foo**]**bar**
               would in a config file). Including the equals but with an
               empty value (like **git -c foo.bar=**...) sets **foo.bar** to the
               empty string which **git config --type=bool** will convert to
               **false**.
    
           --config-env=<name>=<envvar>
               Like **-c** _< name>_**=**_< value>_, give configuration variable _< name>_ a
               value, where <envvar> is the name of an environment variable
               from which to retrieve the value. Unlike **-c** there is no
               shortcut for directly setting the value to an empty string,
               instead the environment variable itself must be set to the
               empty string. It is an error if the _< envvar>_ does not exist in
               the environment.  _< envvar>_ may not contain an equals sign to
               avoid ambiguity with _< name>_ containing one.
    
               This is useful for cases where you want to pass transitory
               configuration options to git, but are doing so on operating
               systems where other processes might be able to read your
               command line (e.g.  **/proc/self/cmdline**), but not your
               environment (e.g.  **/proc/self/environ**). That behavior is the
               default on Linux, but may not be on your system.
    
               Note that this might add security for variables such as
               **http.extraHeader** where the sensitive information is part of
               the value, but not e.g.  **url.**_< base>_**.insteadOf** where the
               sensitive information can be part of the key.
    
           --exec-path[=<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.
    
           --html-path
               Print the path, without trailing slash, where Git’s HTML
               documentation is installed and exit.
    
           --man-path
               Print the manpath (see **man**(**1**)) for the man pages for this
               version of Git and exit.
    
           --info-path
               Print the path where the Info files documenting this version
               of Git are installed and exit.
    
           -p, --paginate
               Pipe all output into _less_ (or if set, $PAGER) if standard
               output is a terminal. This overrides the **pager.**_< cmd>_
               configuration options (see the "Configuration Mechanism"
               section below).
    
           -P, --no-pager
               Do not pipe Git output into a pager.
    
           --git-dir=<path>
               Set the path to the repository (".git" directory). This can
               also be controlled by setting the **GIT_DIR** environment
               variable. It can be an absolute path or relative path to
               current working directory.
    
               Specifying the location of the ".git" directory using this
               option (or **GIT_DIR** environment variable) turns off the
               repository discovery that tries to find a directory with
               ".git" subdirectory (which is how the repository and the
               top-level of the working tree are discovered), and tells Git
               that you are at the top level of the working tree. If you are
               not at the top-level directory of the working tree, you should
               tell Git where the top-level of the working tree is, with the
               **--work-tree=**_< path>_ option (or **GIT_WORK_TREE** environment
               variable)
    
               If you just want to run git as if it was started in _< path>_
               then use **git -C** _< path>_.
    
           --work-tree=<path>
               Set the path to the working tree. It can be an absolute path
               or a path relative to the current working directory. This can
               also be controlled by setting the GIT_WORK_TREE environment
               variable and the core.worktree configuration variable (see
               core.worktree in git-config(1) for a more detailed
               discussion).
    
           --namespace=<path>
               Set the Git namespace. See gitnamespaces(7) for more details.
               Equivalent to setting the **GIT_NAMESPACE** environment variable.
    
           --bare
               Treat the repository as a bare repository. If GIT_DIR
               environment is not set, it is set to the current working
               directory.
    
           --no-replace-objects
               Do not use replacement refs to replace Git objects. This is
               equivalent to exporting the **GIT_NO_REPLACE_OBJECTS** environment
               variable with any value. See git-replace(1) for more
               information.
    
           --no-lazy-fetch
               Do not fetch missing objects from the promisor remote on
               demand. Useful together with **git cat-file -e** _< object>_ to see
               if the object is locally available. This is equivalent to
               setting the **GIT_NO_LAZY_FETCH** environment variable to **1**.
    
           --no-optional-locks
               Do not perform optional operations that require locks. This is
               equivalent to setting the **GIT_OPTIONAL_LOCKS** to **0**.
    
           --no-advice
               Disable all advice hints from being printed.
    
           --literal-pathspecs
               Treat pathspecs literally (i.e. no globbing, no pathspec
               magic). This is equivalent to setting the
               **GIT_LITERAL_PATHSPECS** environment variable to **1**.
    
           --glob-pathspecs
               Add "glob" magic to all pathspec. This is equivalent to
               setting the **GIT_GLOB_PATHSPECS** environment variable to **1**.
               Disabling globbing on individual pathspecs can be done using
               pathspec magic ":(literal)"
    
           --noglob-pathspecs
               Add "literal" magic to all pathspec. This is equivalent to
               setting the **GIT_NOGLOB_PATHSPECS** environment variable to **1**.
               Enabling globbing on individual pathspecs can be done using
               pathspec magic ":(glob)"
    
           --icase-pathspecs
               Add "icase" magic to all pathspec. This is equivalent to
               setting the **GIT_ICASE_PATHSPECS** environment variable to **1**.
    
           --list-cmds=<group>[,<group>...]
               List commands by group. This is an internal/experimental
               option and may change or be removed in the future. Supported
               groups are: builtins, parseopt (builtin commands that use
               parse-options), main (all commands in libexec directory),
               others (all other commands in **$PATH** that have git- prefix),
               list-<category> (see categories in command-list.txt),
               nohelpers (exclude helper commands), alias and config
               (retrieve command list from config variable
               completion.commands)
    
           --attr-source=<tree-ish>
               Read gitattributes from <tree-ish> instead of the worktree.
               See gitattributes(5). This is equivalent to setting the
               **GIT_ATTR_SOURCE** environment variable.
    


## GIT COMMANDS



           We divide Git into high level ("porcelain") commands and low level
           ("plumbing") commands.
    


## HIGH-LEVEL COMMANDS (PORCELAIN)



           We separate the porcelain commands into the main commands and some
           ancillary user utilities.
    
       **Main porcelain commands**
           git-add(1)
               Add file contents to the index.
    
           git-am(1)
               Apply a series of patches from a mailbox.
    
           git-archive(1)
               Create an archive of files from a named tree.
    
           git-backfill(1)
               Download missing objects in a partial clone.
    
           git-bisect(1)
               Use binary search to find the commit that introduced a bug.
    
           git-branch(1)
               List, create, or delete branches.
    
           git-bundle(1)
               Move objects and refs by archive.
    
           git-checkout(1)
               Switch branches or restore working tree files.
    
           git-cherry-pick(1)
               Apply the changes introduced by some existing commits.
    
           git-citool(1)
               Graphical alternative to git-commit.
    
           git-clean(1)
               Remove untracked files from the working tree.
    
           git-clone(1)
               Clone a repository into a new directory.
    
           git-commit(1)
               Record changes to the repository.
    
           git-describe(1)
               Give an object a human readable name based on an available
               ref.
    
           git-diff(1)
               Show changes between commits, commit and working tree, etc.
    
           git-fetch(1)
               Download objects and refs from another repository.
    
           git-format-patch(1)
               Prepare patches for e-mail submission.
    
           git-gc(1)
               Cleanup unnecessary files and optimize the local repository.
    
           git-grep(1)
               Print lines matching a pattern.
    
           git-gui(1)
               A portable graphical interface to Git.
    
           git-init(1)
               Create an empty Git repository or reinitialize an existing
               one.
    
           git-log(1)
               Show commit logs.
    
           git-maintenance(1)
               Run tasks to optimize Git repository data.
    
           git-merge(1)
               Join two or more development histories together.
    
           git-mv(1)
               Move or rename a file, a directory, or a symlink.
    
           git-notes(1)
               Add or inspect object notes.
    
           git-pull(1)
               Fetch from and integrate with another repository or a local
               branch.
    
           git-push(1)
               Update remote refs along with associated objects.
    
           git-range-diff(1)
               Compare two commit ranges (e.g. two versions of a branch).
    
           git-rebase(1)
               Reapply commits on top of another base tip.
    
           git-reset(1)
               Reset current HEAD to the specified state.
    
           git-restore(1)
               Restore working tree files.
    
           git-revert(1)
               Revert some existing commits.
    
           git-rm(1)
               Remove files from the working tree and from the index.
    
           git-shortlog(1)
               Summarize _git log_ output.
    
           git-show(1)
               Show various types of objects.
    
           git-sparse-checkout(1)
               Reduce your working tree to a subset of tracked files.
    
           git-stash(1)
               Stash the changes in a dirty working directory away.
    
           git-status(1)
               Show the working tree status.
    
           git-submodule(1)
               Initialize, update or inspect submodules.
    
           git-switch(1)
               Switch branches.
    
           git-tag(1)
               Create, list, delete or verify a tag object signed with GPG.
    
           git-worktree(1)
               Manage multiple working trees.
    
           gitk(1)
               The Git repository browser.
    
           scalar(1)
               A tool for managing large Git repositories.
    
       **Ancillary Commands**
           Manipulators:
    
           git-config(1)
               Get and set repository or global options.
    
           git-fast-export(1)
               Git data exporter.
    
           git-fast-import(1)
               Backend for fast Git data importers.
    
           git-filter-branch(1)
               Rewrite branches.
    
           git-mergetool(1)
               Run merge conflict resolution tools to resolve merge
               conflicts.
    
           git-pack-refs(1)
               Pack heads and tags for efficient repository access.
    
           git-prune(1)
               Prune all unreachable objects from the object database.
    
           git-reflog(1)
               Manage reflog information.
    
           git-refs(1)
               Low-level access to refs.
    
           git-remote(1)
               Manage set of tracked repositories.
    
           git-repack(1)
               Pack unpacked objects in a repository.
    
           git-replace(1)
               Create, list, delete refs to replace objects.
    
           Interrogators:
    
           git-annotate(1)
               Annotate file lines with commit information.
    
           git-blame(1)
               Show what revision and author last modified each line of a
               file.
    
           git-bugreport(1)
               Collect information for user to file a bug report.
    
           git-count-objects(1)
               Count unpacked number of objects and their disk consumption.
    
           git-diagnose(1)
               Generate a zip archive of diagnostic information.
    
           git-difftool(1)
               Show changes using common diff tools.
    
           git-fsck(1)
               Verifies the connectivity and validity of the objects in the
               database.
    
           git-help(1)
               Display help information about Git.
    
           git-instaweb(1)
               Instantly browse your working repository in gitweb.
    
           git-merge-tree(1)
               Perform merge without touching index or working tree.
    
           git-rerere(1)
               Reuse recorded resolution of conflicted merges.
    
           git-show-branch(1)
               Show branches and their commits.
    
           git-verify-commit(1)
               Check the GPG signature of commits.
    
           git-verify-tag(1)
               Check the GPG signature of tags.
    
           git-version(1)
               Display version information about Git.
    
           git-whatchanged(1)
               Show logs with differences each commit introduces.
    
           gitweb(1)
               Git web interface (web frontend to Git repositories).
    
       **Interacting with Others**
           These commands are to interact with foreign SCM and with other
           people via patch over e-mail.
    
           git-archimport(1)
               Import a GNU Arch repository into Git.
    
           git-cvsexportcommit(1)
               Export a single commit to a CVS checkout.
    
           git-cvsimport(1)
               Salvage your data out of another SCM people love to hate.
    
           git-cvsserver(1)
               A CVS server emulator for Git.
    
           git-imap-send(1)
               Send a collection of patches from stdin to an IMAP folder.
    
           git-p4(1)
               Import from and submit to Perforce repositories.
    
           git-quiltimport(1)
               Applies a quilt patchset onto the current branch.
    
           git-request-pull(1)
               Generates a summary of pending changes.
    
           git-send-email(1)
               Send a collection of patches as emails.
    
           git-svn(1)
               Bidirectional operation between a Subversion repository and
               Git.
    
       **Reset, restore and revert**
           There are three commands with similar names: **git reset** , **git**
           **restore** and **git revert**.
    
           •   git-revert(1) is about making a new commit that reverts the
               changes made by other commits.
    
           •   git-restore(1) is about restoring files in the working tree
               from either the index or another commit. This command does not
               update your branch. The command can also be used to restore
               files in the index from another commit.
    
           •   git-reset(1) is about updating your branch, moving the tip in
               order to add or remove commits from the branch. This operation
               changes the commit history.
    
               **git reset** can also be used to restore the index, overlapping
               with **git restore**.
    


## LOW-LEVEL COMMANDS (PLUMBING)



           Although Git includes its own porcelain layer, its low-level
           commands are sufficient to support development of alternative
           porcelains. Developers of such porcelains might start by reading
           about git-update-index(1) and git-read-tree(1).
    
           The interface (input, output, set of options and the semantics) to
           these low-level commands are meant to be a lot more stable than
           Porcelain level commands, because these commands are primarily for
           scripted use. The interface to Porcelain commands on the other
           hand are subject to change in order to improve the end user
           experience.
    
           The following description divides the low-level commands into
           commands that manipulate objects (in the repository, index, and
           working tree), commands that interrogate and compare objects, and
           commands that move objects and references between repositories.
    
       **Manipulation commands**
           git-apply(1)
               Apply a patch to files and/or to the index.
    
           git-checkout-index(1)
               Copy files from the index to the working tree.
    
           git-commit-graph(1)
               Write and verify Git commit-graph files.
    
           git-commit-tree(1)
               Create a new commit object.
    
           git-hash-object(1)
               Compute object ID and optionally create an object from a file.
    
           git-index-pack(1)
               Build pack index file for an existing packed archive.
    
           git-merge-file(1)
               Run a three-way file merge.
    
           git-merge-index(1)
               Run a merge for files needing merging.
    
           git-mktag(1)
               Creates a tag object with extra validation.
    
           git-mktree(1)
               Build a tree-object from ls-tree formatted text.
    
           git-multi-pack-index(1)
               Write and verify multi-pack-indexes.
    
           git-pack-objects(1)
               Create a packed archive of objects.
    
           git-prune-packed(1)
               Remove extra objects that are already in pack files.
    
           git-read-tree(1)
               Reads tree information into the index.
    
           git-replay(1)
               EXPERIMENTAL: Replay commits on a new base, works with bare
               repos too.
    
           git-symbolic-ref(1)
               Read, modify and delete symbolic refs.
    
           git-unpack-objects(1)
               Unpack objects from a packed archive.
    
           git-update-index(1)
               Register file contents in the working tree to the index.
    
           git-update-ref(1)
               Update the object name stored in a ref safely.
    
           git-write-tree(1)
               Create a tree object from the current index.
    
       **Interrogation commands**
           git-cat-file(1)
               Provide contents or details of repository objects.
    
           git-cherry(1)
               Find commits yet to be applied to upstream.
    
           git-diff-files(1)
               Compares files in the working tree and the index.
    
           git-diff-index(1)
               Compare a tree to the working tree or index.
    
           git-diff-pairs(1)
               Compare the content and mode of provided blob pairs.
    
           git-diff-tree(1)
               Compares the content and mode of blobs found via two tree
               objects.
    
           git-for-each-ref(1)
               Output information on each ref.
    
           git-for-each-repo(1)
               Run a Git command on a list of repositories.
    
           git-get-tar-commit-id(1)
               Extract commit ID from an archive created using git-archive.
    
           git-ls-files(1)
               Show information about files in the index and the working
               tree.
    
           git-ls-remote(1)
               List references in a remote repository.
    
           git-ls-tree(1)
               List the contents of a tree object.
    
           git-merge-base(1)
               Find as good common ancestors as possible for a merge.
    
           git-name-rev(1)
               Find symbolic names for given revs.
    
           git-pack-redundant(1)
               Find redundant pack files.
    
           git-rev-list(1)
               Lists commit objects in reverse chronological order.
    
           git-rev-parse(1)
               Pick out and massage parameters.
    
           git-show-index(1)
               Show packed archive index.
    
           git-show-ref(1)
               List references in a local repository.
    
           git-unpack-file(1)
               Creates a temporary file with a blob’s contents.
    
           git-var(1)
               Show a Git logical variable.
    
           git-verify-pack(1)
               Validate packed Git archive files.
    
           In general, the interrogate commands do not touch the files in the
           working tree.
    
       **Syncing repositories**
           git-daemon(1)
               A really simple server for Git repositories.
    
           git-fetch-pack(1)
               Receive missing objects from another repository.
    
           git-http-backend(1)
               Server side implementation of Git over HTTP.
    
           git-send-pack(1)
               Push objects over Git protocol to another repository.
    
           git-update-server-info(1)
               Update auxiliary info file to help dumb servers.
    
           The following are helper commands used by the above; end users
           typically do not use them directly.
    
           git-http-fetch(1)
               Download from a remote Git repository via HTTP.
    
           git-http-push(1)
               Push objects over HTTP/DAV to another repository.
    
           git-receive-pack(1)
               Receive what is pushed into the repository.
    
           git-shell(1)
               Restricted login shell for Git-only SSH access.
    
           git-upload-archive(1)
               Send archive back to git-archive.
    
           git-upload-pack(1)
               Send objects packed back to git-fetch-pack.
    
       **Internal helper commands**
           These are internal helper commands used by other commands; end
           users typically do not use them directly.
    
           git-check-attr(1)
               Display gitattributes information.
    
           git-check-ignore(1)
               Debug gitignore / exclude files.
    
           git-check-mailmap(1)
               Show canonical names and email addresses of contacts.
    
           git-check-ref-format(1)
               Ensures that a reference name is well formed.
    
           git-column(1)
               Display data in columns.
    
           git-credential(1)
               Retrieve and store user credentials.
    
           git-credential-cache(1)
               Helper to temporarily store passwords in memory.
    
           git-credential-store(1)
               Helper to store credentials on disk.
    
           git-fmt-merge-msg(1)
               Produce a merge commit message.
    
           git-hook(1)
               Run git hooks.
    
           git-interpret-trailers(1)
               Add or parse structured information in commit messages.
    
           git-mailinfo(1)
               Extracts patch and authorship from a single e-mail message.
    
           git-mailsplit(1)
               Simple UNIX mbox splitter program.
    
           git-merge-one-file(1)
               The standard helper program to use with git-merge-index.
    
           git-patch-id(1)
               Compute unique ID for a patch.
    
           git-sh-i18n(1)
               Git’s i18n setup code for shell scripts.
    
           git-sh-setup(1)
               Common Git shell script setup code.
    
           git-stripspace(1)
               Remove unnecessary whitespace.
    


## GUIDES



           The following documentation pages are guides about Git concepts.
    
           gitcore-tutorial(7)
               A Git core tutorial for developers.
    
           gitcredentials(7)
               Providing usernames and passwords to Git.
    
           gitcvs-migration(7)
               Git for CVS users.
    
           gitdiffcore(7)
               Tweaking diff output.
    
           giteveryday(7)
               A useful minimum set of commands for Everyday Git.
    
           gitfaq(7)
               Frequently asked questions about using Git.
    
           gitglossary(7)
               A Git Glossary.
    
           gitnamespaces(7)
               Git namespaces.
    
           gitremote-helpers(7)
               Helper programs to interact with remote repositories.
    
           gitsubmodules(7)
               Mounting one repository inside another.
    
           gittutorial(7)
               A tutorial introduction to Git.
    
           gittutorial-2(7)
               A tutorial introduction to Git: part two.
    
           gitworkflows(7)
               An overview of recommended workflows with Git.
    


## REPOSITORY, COMMAND AND FILE INTERFACES



           This documentation discusses repository and command interfaces
           which users are expected to interact with directly. See
           **--user-formats** in git-help(1) for more details on the criteria.
    
           gitattributes(5)
               Defining attributes per path.
    
           gitcli(7)
               Git command-line interface and conventions.
    
           githooks(5)
               Hooks used by Git.
    
           gitignore(5)
               Specifies intentionally untracked files to ignore.
    
           gitmailmap(5)
               Map author/committer names and/or E-Mail addresses.
    
           gitmodules(5)
               Defining submodule properties.
    
           gitrepository-layout(5)
               Git Repository Layout.
    
           gitrevisions(7)
               Specifying revisions and ranges for Git.
    


## FILE FORMATS, PROTOCOLS AND OTHER DEVELOPER INTERFACES



           This documentation discusses file formats, over-the-wire protocols
           and other git developer interfaces. See **--developer-interfaces** in
           git-help(1).
    
           gitformat-bundle(5)
               The bundle file format.
    
           gitformat-chunk(5)
               Chunk-based file formats.
    
           gitformat-commit-graph(5)
               Git commit-graph format.
    
           gitformat-index(5)
               Git index format.
    
           gitformat-pack(5)
               Git pack format.
    
           gitformat-signature(5)
               Git cryptographic signature formats.
    
           gitprotocol-capabilities(5)
               Protocol v0 and v1 capabilities.
    
           gitprotocol-common(5)
               Things common to various protocols.
    
           gitprotocol-http(5)
               Git HTTP-based protocols.
    
           gitprotocol-pack(5)
               How packs are transferred over-the-wire.
    
           gitprotocol-v2(5)
               Git Wire Protocol, Version 2.
    


## CONFIGURATION MECHANISM



           Git uses a simple text format to store customizations that are per
           repository and are per user. Such a configuration file may look
           like this:
    
               #
               # A '#' or ';' character indicates a comment.
               #
    
               ; core variables
               [core]
                       ; Don't trust file modes
                       filemode = false
    
               ; user identity
               [user]
                       name = "Junio C Hamano"
                       email = "gitster@pobox.com"
    
           Various commands read from the configuration file and adjust their
           operation accordingly. See git-config(1) for a list and more
           details about the configuration mechanism.
    


## 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>.
    
           <commit-ish>
               Indicates a commit or tag object name. A command that takes a
               <commit-ish> argument ultimately wants to operate on a
               <commit> object but automatically dereferences <tag> objects
               that point at a <commit>.
    
           <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.
    
           <tag>
               a valid tag _name_ (i.e. a **refs/tags/**_< tag>_ reference).
    
           <head>
               a valid head _name_ (i.e. a **refs/heads/**_< head>_ reference).
    
           For a more complete list of ways to spell object names, see
           "SPECIFYING REVISIONS" section in gitrevisions(7).
    


## FILE/DIRECTORY STRUCTURE



           Please see the gitrepository-layout(5) document.
    
           Read githooks(5) for more details about each hook.
    
           Higher level SCMs may provide and manage additional information in
           the **$GIT_DIR**.
    


## TERMINOLOGY



           Please see gitglossary(7).
    


## ENVIRONMENT VARIABLES



           Various Git commands pay attention to environment variables and
           change their behavior. The environment variables marked as
           "Boolean" take their values the same way as Boolean valued
           configuration variables, i.e., "true", "yes", "on" and positive
           numbers are taken as "yes", while "false", "no", "off", and "0"
           are taken as "no".
    
           Here are the variables:
    
       **System**
           **HOME**
               Specifies the path to the user’s home directory. On Windows,
               if unset, Git will set a process environment variable equal
               to: **$HOMEDRIVE$HOMEPATH** if both **$HOMEDRIVE** and **$HOMEPATH**
               exist; otherwise **$USERPROFILE** if **$USERPROFILE** exists.
    
       **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 a foreign front-end.
    
           **GIT_INDEX_FILE**
               This environment variable specifies an alternate index file.
               If not specified, the default of **$GIT_DIR/index** is used.
    
           **GIT_INDEX_VERSION**
               This environment variable specifies what index version is used
               when writing the index file out. It won’t affect existing
               index files. By default index file version 2 or 3 is used. See
               git-update-index(1) for more information.
    
           **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 (on Windows ";" separated) list of
               Git object directories which can be used to search for Git
               objects. New objects will not be written to these directories.
    
               Entries that begin with " (double-quote) will be interpreted
               as C-style quoted paths, removing leading and trailing
               double-quotes and respecting backslash escapes. E.g., the
               value "path-with-\"-and-:-in-it":vanilla-path has two paths:
               **path-with-** "-and-:-in-it and **vanilla-path**.
    
           **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. The **--git-dir** command-line option also sets this
               value.
    
           **GIT_WORK_TREE**
               Set the path to the root of the working tree. This can also be
               controlled by the **--work-tree** command-line option and the
               core.worktree configuration variable.
    
           **GIT_NAMESPACE**
               Set the Git namespace; see gitnamespaces(7) for details. The
               **--namespace** command-line option also sets this value.
    
           **GIT_CEILING_DIRECTORIES**
               This should be a colon-separated list of absolute paths. If
               set, it is a list of directories that Git should not chdir up
               into while looking for a repository directory (useful for
               excluding slow-loading network directories). It will not
               exclude the current working directory or a GIT_DIR set on the
               command line or in the environment. Normally, Git has to read
               the entries in this list and resolve any symlink that might be
               present in order to compare them with the current directory.
               However, if even this access is slow, you can add an empty
               entry to the list to tell Git that the subsequent entries are
               not symlinks and needn’t be resolved; e.g.,
               **GIT_CEILING_DIRECTORIES=/maybe/symlink::/very/slow/non/symlink**.
    
           **GIT_DISCOVERY_ACROSS_FILESYSTEM**
               When run in a directory that does not have ".git" repository
               directory, Git tries to find such a directory in the parent
               directories to find the top of the working tree, but by
               default it does not cross filesystem boundaries. This Boolean
               environment variable can be set to true to tell Git not to
               stop at filesystem boundaries. Like **GIT_CEILING_DIRECTORIES** ,
               this will not affect an explicit repository directory set via
               **GIT_DIR** or on the command line.
    
           **GIT_COMMON_DIR**
               If this variable is set to a path, non-worktree files that are
               normally in $GIT_DIR will be taken from this path instead.
               Worktree-specific files such as HEAD or index are taken from
               $GIT_DIR. See gitrepository-layout(5) and git-worktree(1) for
               details. This variable has lower precedence than other path
               variables such as GIT_INDEX_FILE, GIT_OBJECT_DIRECTORY...
    
           **GIT_DEFAULT_HASH**
               If this variable is set, the default hash algorithm for new
               repositories will be set to this value. This value is ignored
               when cloning and the setting of the remote repository is
               always used. The default is "sha1". See **--object-format** in
               git-init(1).
    
           **GIT_DEFAULT_REF_FORMAT**
               If this variable is set, the default reference backend format
               for new repositories will be set to this value. The default is
               "files". See **--ref-format** in git-init(1).
    
       **Git Commits**
           **GIT_AUTHOR_NAME**
               The human-readable name used in the author identity when
               creating commit or tag objects, or when writing reflogs.
               Overrides the **user.name** and **author.name** configuration
               settings.
    
           **GIT_AUTHOR_EMAIL**
               The email address used in the author identity when creating
               commit or tag objects, or when writing reflogs. Overrides the
               **user.email** and **author.email** configuration settings.
    
           **GIT_AUTHOR_DATE**
               The date used for the author identity when creating commit or
               tag objects, or when writing reflogs. See git-commit(1) for
               valid formats.
    
           **GIT_COMMITTER_NAME**
               The human-readable name used in the committer identity when
               creating commit or tag objects, or when writing reflogs.
               Overrides the **user.name** and **committer.name** configuration
               settings.
    
           **GIT_COMMITTER_EMAIL**
               The email address used in the author identity when creating
               commit or tag objects, or when writing reflogs. Overrides the
               **user.email** and **committer.email** configuration settings.
    
           **GIT_COMMITTER_DATE**
               The date used for the committer identity when creating commit
               or tag objects, or when writing reflogs. See git-commit(1) for
               valid formats.
    
           **EMAIL**
               The email address used in the author and committer identities
               if no other relevant environment variable or configuration
               setting has been set.
    
       **Git Diffs**
           **GIT_DIFF_OPTS**
               Only valid setting is "--unified=??" or "-u??" to set the
               number of context lines shown when a unified diff is created.
               This takes precedence over any "-U" or "--unified" option
               value passed on the Git diff command line.
    
           **GIT_EXTERNAL_DIFF**
               When the environment variable **GIT_EXTERNAL_DIFF** is set, the
               program named by it is called to generate diffs, and Git does
               not use its builtin diff machinery. For a path that is added,
               removed, or modified, **GIT_EXTERNAL_DIFF** is called with 7
               parameters:
    
                   path old-file old-hex old-mode new-file new-hex new-mode
    
               where:
    
           <old|new>-file
               are files GIT_EXTERNAL_DIFF can use to read the contents of
               <old|new>,
    
           <old|new>-hex
               are the 40-hexdigit SHA-1 hashes,
    
           <old|new>-mode
               are the octal representation of the file modes.
    
               The file parameters can point at the user’s working file (e.g.
               **new-file** in "git-diff-files"), **/dev/null**(e.g.  **old-file** when
               a new file is added), or a temporary file (e.g.  **old-file** in
               the index).  **GIT_EXTERNAL_DIFF** should not worry about
               unlinking the temporary file — it is removed when
               **GIT_EXTERNAL_DIFF** exits.
    
               For a path that is unmerged, **GIT_EXTERNAL_DIFF** is called with
               1 parameter, <path>.
    
               For each path **GIT_EXTERNAL_DIFF** is called, two environment
               variables, **GIT_DIFF_PATH_COUNTER** and **GIT_DIFF_PATH_TOTAL** are
               set.
    
           **GIT_EXTERNAL_DIFF_TRUST_EXIT_CODE**
               If this Boolean environment variable is set to true then the
               **GIT_EXTERNAL_DIFF** command is expected to return exit code 0 if
               it considers the input files to be equal or 1 if it considers
               them to be different, like **diff**(**1**). If it is set to false,
               which is the default, then the command is expected to return
               exit code 0 regardless of equality. Any other exit code causes
               Git to report a fatal error.
    
           **GIT_DIFF_PATH_COUNTER**
               A 1-based counter incremented by one for every path.
    
           **GIT_DIFF_PATH_TOTAL**
               The total number of paths.
    
       **other**
           **GIT_MERGE_VERBOSITY**
               A number controlling the amount of output shown by the
               recursive merge strategy. Overrides merge.verbosity. See
               git-merge(1)
    
           **GIT_PAGER**
               This environment variable overrides **$PAGER**. If it is set to an
               empty string or to the value "cat", Git will not launch a
               pager. See also the **core.pager** option in git-config(1).
    
           **GIT_PROGRESS_DELAY**
               A number controlling how many seconds to delay before showing
               optional progress indicators. Defaults to 2.
    
           **GIT_EDITOR**
               This environment variable overrides **$EDITOR** and **$VISUAL**. It is
               used by several Git commands when, on interactive mode, an
               editor is to be launched. See also git-var(1) and the
               **core.editor** option in git-config(1).
    
           **GIT_SEQUENCE_EDITOR**
               This environment variable overrides the configured Git editor
               when editing the todo list of an interactive rebase. See also
               git-rebase(1) and the **sequence.editor** option in git-config(1).
    
           **GIT_SSH** , **GIT_SSH_COMMAND**
               If either of these environment variables is set then _git fetch_
               and _git push_ will use the specified command instead of _ssh_
               when they need to connect to a remote system. The command-line
               parameters passed to the configured command are determined by
               the ssh variant. See **ssh.variant** option in git-config(1) for
               details.
    
               **$GIT_SSH_COMMAND** takes precedence over **$GIT_SSH** , and is
               interpreted by the shell, which allows additional arguments to
               be included.  **$GIT_SSH** on the other hand must be just the path
               to a program (which can be a wrapper shell script, if
               additional arguments are needed).
    
               Usually it is easier to configure any desired options through
               your personal **.ssh/config** file. Please consult your ssh
               documentation for further details.
    
           **GIT_SSH_VARIANT**
               If this environment variable is set, it overrides Git’s
               autodetection whether **GIT_SSH** /**GIT_SSH_COMMAND** /**core.sshCommand**
               refer to OpenSSH, plink or tortoiseplink. This variable
               overrides the config setting **ssh.variant** that serves the same
               purpose.
    
           **GIT_SSL_NO_VERIFY**
               Setting and exporting this environment variable to any value
               tells Git not to verify the SSL certificate when fetching or
               pushing over HTTPS.
    
           **GIT_ATTR_SOURCE**
               Sets the treeish that gitattributes will be read from.
    
           **GIT_ASKPASS**
               If this environment variable is set, then Git commands which
               need to acquire passwords or passphrases (e.g. for HTTP or
               IMAP authentication) will call this program with a suitable
               prompt as command-line argument and read the password from its
               STDOUT. See also the **core.askPass** option in git-config(1).
    
           **GIT_TERMINAL_PROMPT**
               If this Boolean environment variable is set to false, git will
               not prompt on the terminal (e.g., when asking for HTTP
               authentication).
    
           **GIT_CONFIG_GLOBAL** , **GIT_CONFIG_SYSTEM**
               Take the configuration from the given files instead from
               global or system-level configuration files. If
               **GIT_CONFIG_SYSTEM** is set, the system config file defined at
               build time (usually **/etc/gitconfig**) will not be read.
               Likewise, if **GIT_CONFIG_GLOBAL** is set, neither
               **$HOME/.gitconfig** nor **$XDG_CONFIG_HOME/git/config** will be read.
               Can be set to **/dev/null** to skip reading configuration files of
               the respective level.
    
           **GIT_CONFIG_NOSYSTEM**
               Whether to skip reading settings from the system-wide
               **$**(**prefix**)**/etc/gitconfig** file. This Boolean environment
               variable can be used along with **$HOME** and **$XDG_CONFIG_HOME** to
               create a predictable environment for a picky script, or you
               can set it to true to temporarily avoid using a buggy
               **/etc/gitconfig** file while waiting for someone with sufficient
               permissions to fix it.
    
           **GIT_FLUSH**
               If this Boolean environment variable is set to true, then
               commands such as _git blame_ (in incremental mode), _git_
               _rev-list_ , _git log_ , _git check-attr_ and _git check-ignore_ will
               force a flush of the output stream after each record have been
               flushed. If this variable is set to false, the output of these
               commands will be done using completely buffered I/O. If this
               environment variable is not set, Git will choose buffered or
               record-oriented flushing based on whether stdout appears to be
               redirected to a file or not.
    
           **GIT_TRACE**
               Enables general trace messages, e.g. alias expansion, built-in
               command execution and external command execution.
    
               If this variable is set to "1", "2" or "true" (comparison is
               case insensitive), trace messages will be printed to stderr.
    
               If the variable is set to an integer value greater than 2 and
               lower than 10 (strictly) then Git will interpret this value as
               an open file descriptor and will try to write the trace
               messages into this file descriptor.
    
               Alternatively, if the variable is set to an absolute path
               (starting with a _/_ character), Git will interpret this as a
               file path and will try to append the trace messages to it.
    
               Unsetting the variable, or setting it to empty, "0" or "false"
               (case insensitive) disables trace messages.
    
           **GIT_TRACE_FSMONITOR**
               Enables trace messages for the filesystem monitor extension.
               See **GIT_TRACE** for available trace output options.
    
           **GIT_TRACE_PACK_ACCESS**
               Enables trace messages for all accesses to any packs. For each
               access, the pack file name and an offset in the pack is
               recorded. This may be helpful for troubleshooting some
               pack-related performance problems. See **GIT_TRACE** for available
               trace output options.
    
           **GIT_TRACE_PACKET**
               Enables trace messages for all packets coming in or out of a
               given program. This can help with debugging object negotiation
               or other protocol issues. Tracing is turned off at a packet
               starting with "PACK" (but see **GIT_TRACE_PACKFILE** below). See
               **GIT_TRACE** for available trace output options.
    
           **GIT_TRACE_PACKFILE**
               Enables tracing of packfiles sent or received by a given
               program. Unlike other trace output, this trace is verbatim: no
               headers, and no quoting of binary data. You almost certainly
               want to direct into a file (e.g.,
               **GIT_TRACE_PACKFILE=/tmp/my.pack**) rather than displaying it on
               the terminal or mixing it with other trace output.
    
               Note that this is currently only implemented for the client
               side of clones and fetches.
    
           **GIT_TRACE_PERFORMANCE**
               Enables performance related trace messages, e.g. total
               execution time of each Git command. See **GIT_TRACE** for
               available trace output options.
    
           **GIT_TRACE_REFS**
               Enables trace messages for operations on the ref database. See
               **GIT_TRACE** for available trace output options.
    
           **GIT_TRACE_SETUP**
               Enables trace messages printing the .git, working tree and
               current working directory after Git has completed its setup
               phase. See **GIT_TRACE** for available trace output options.
    
           **GIT_TRACE_SHALLOW**
               Enables trace messages that can help debugging fetching /
               cloning of shallow repositories. See **GIT_TRACE** for available
               trace output options.
    
           **GIT_TRACE_CURL**
               Enables a curl full trace dump of all incoming and outgoing
               data, including descriptive information, of the git transport
               protocol. This is similar to doing curl **--trace-ascii** on the
               command line. See **GIT_TRACE** for available trace output
               options.
    
           **GIT_TRACE_CURL_NO_DATA**
               When a curl trace is enabled (see **GIT_TRACE_CURL** above), do
               not dump data (that is, only dump info lines and headers).
    
           **GIT_TRACE2**
               Enables more detailed trace messages from the "trace2"
               library. Output from **GIT_TRACE2** is a simple text-based format
               for human readability.
    
               If this variable is set to "1", "2" or "true" (comparison is
               case insensitive), trace messages will be printed to stderr.
    
               If the variable is set to an integer value greater than 2 and
               lower than 10 (strictly) then Git will interpret this value as
               an open file descriptor and will try to write the trace
               messages into this file descriptor.
    
               Alternatively, if the variable is set to an absolute path
               (starting with a _/_ character), Git will interpret this as a
               file path and will try to append the trace messages to it. If
               the path already exists and is a directory, the trace messages
               will be written to files (one per process) in that directory,
               named according to the last component of the SID and an
               optional counter (to avoid filename collisions).
    
               In addition, if the variable is set to
               **af_unix:**[_< socket-type>_**:**]_< absolute-pathname>_, Git will try to
               open the path as a Unix Domain Socket. The socket type can be
               either **stream** or **dgram**.
    
               Unsetting the variable, or setting it to empty, "0" or "false"
               (case insensitive) disables trace messages.
    
               See **Trace2 documentation******[2] for full details.**GIT_TRACE2_EVENT**
               This setting writes a JSON-based format that is suited for
               machine interpretation. See **GIT_TRACE2** for available trace
               output options and **Trace2 documentation******[2] for full details.**GIT_TRACE2_PERF**
               In addition to the text-based messages available in
               **GIT_TRACE2** , this setting writes a column-based format for
               understanding nesting regions. See **GIT_TRACE2** for available
               trace output options and **Trace2 documentation******[2] for full
               details.**GIT_TRACE_REDACT**
               By default, when tracing is activated, Git redacts the values
               of cookies, the "Authorization:" header, the
               "Proxy-Authorization:" header and packfile URIs. Set this
               Boolean environment variable to false to prevent this
               redaction.
    
           **GIT_NO_REPLACE_OBJECTS**
               Setting and exporting this environment variable tells Git to
               ignore replacement refs and do not replace Git objects.
    
           **GIT_LITERAL_PATHSPECS**
               Setting this Boolean environment variable to true will cause
               Git to treat all pathspecs literally, rather than as glob
               patterns. For example, running **GIT_LITERAL_PATHSPECS=1 git log**
               **--** '*.c' will search for commits that touch the path ***.c** , not
               any paths that the glob ***.c** matches. You might want this if
               you are feeding literal paths to Git (e.g., paths previously
               given to you by **git ls-tree** , **--raw** diff output, etc).
    
           **GIT_GLOB_PATHSPECS**
               Setting this Boolean environment variable to true will cause
               Git to treat all pathspecs as glob patterns (aka "glob"
               magic).
    
           **GIT_NOGLOB_PATHSPECS**
               Setting this Boolean environment variable to true will cause
               Git to treat all pathspecs as literal (aka "literal" magic).
    
           **GIT_ICASE_PATHSPECS**
               Setting this Boolean environment variable to true will cause
               Git to treat all pathspecs as case-insensitive.
    
           **GIT_NO_LAZY_FETCH**
               Setting this Boolean environment variable to true tells Git
               not to lazily fetch missing objects from the promisor remote
               on demand.
    
           **GIT_REFLOG_ACTION**
               When a ref is updated, reflog entries are created to keep
               track of the reason why the ref was updated (which is
               typically the name of the high-level command that updated the
               ref), in addition to the old and new values of the ref. A
               scripted Porcelain command can use set_reflog_action helper
               function in **git-sh-setup** to set its name to this variable when
               it is invoked as the top level command by the end user, to be
               recorded in the body of the reflog.
    
           **GIT_REF_PARANOIA**
               If this Boolean environment variable is set to false, ignore
               broken or badly named refs when iterating over lists of refs.
               Normally Git will try to include any such refs, which may
               cause some operations to fail. This is usually preferable, as
               potentially destructive operations (e.g., git-prune(1)) are
               better off aborting rather than ignoring broken refs (and thus
               considering the history they point to as not worth saving).
               The default value is **1**(i.e., be paranoid about detecting and
               aborting all operations). You should not normally need to set
               this to **0** , but it may be useful when trying to salvage data
               from a corrupted repository.
    
           **GIT_COMMIT_GRAPH_PARANOIA**
               When loading a commit object from the commit-graph, Git
               performs an existence check on the object in the object
               database. This is done to avoid issues with stale
               commit-graphs that contain references to already-deleted
               commits, but comes with a performance penalty.
    
               The default is "false", which disables the aforementioned
               behavior. Setting this to "true" enables the existence check
               so that stale commits will never be returned from the
               commit-graph at the cost of performance.
    
           **GIT_ALLOW_PROTOCOL**
               If set to a colon-separated list of protocols, behave as if
               **protocol.allow** is set to **never** , and each of the listed
               protocols has **protocol.**_< name>_**.allow** set to **always**(overriding
               any existing configuration). See the description of
               **protocol.allow** in git-config(1) for more details.
    
           **GIT_PROTOCOL_FROM_USER**
               Set this Boolean environment variable to false to prevent
               protocols used by fetch/push/clone which are configured to the
               **user** state. This is useful to restrict recursive submodule
               initialization from an untrusted repository or for programs
               which feed potentially-untrusted URLS to git commands. See
               git-config(1) for more details.
    
           **GIT_PROTOCOL**
               For internal use only. Used in handshaking the wire protocol.
               Contains a colon _:_ separated list of keys with optional values
               _< key>[=<value>]_. Presence of unknown keys and values must be
               ignored.
    
               Note that servers may need to be configured to allow this
               variable to pass over some transports. It will be propagated
               automatically when accessing local repositories (i.e., **file://**
               or a filesystem path), as well as over the **git://** protocol.
               For git-over-http, it should work automatically in most
               configurations, but see the discussion in git-http-backend(1).
               For git-over-ssh, the ssh server may need to be configured to
               allow clients to pass this variable (e.g., by using **AcceptEnv**
               **GIT_PROTOCOL** with OpenSSH).
    
               This configuration is optional. If the variable is not
               propagated, then clients will fall back to the original "v0"
               protocol (but may miss out on some performance improvements or
               features). This variable currently only affects clones and
               fetches; it is not yet used for pushes (but may be in the
               future).
    
           **GIT_OPTIONAL_LOCKS**
               If this Boolean environment variable is set to false, Git will
               complete any requested operation without performing any
               optional sub-operations that require taking a lock. For
               example, this will prevent **git status** from refreshing the
               index as a side effect. This is useful for processes running
               in the background which do not want to cause lock contention
               with other operations on the repository. Defaults to **1**.
    
           **GIT_REDIRECT_STDIN** , **GIT_REDIRECT_STDOUT** , **GIT_REDIRECT_STDERR**
               Windows-only: allow redirecting the standard
               input/output/error handles to paths specified by the
               environment variables. This is particularly useful in
               multi-threaded applications where the canonical way to pass
               standard handles via **CreateProcess**() is not an option because
               it would require the handles to be marked inheritable (and
               consequently **every** spawned process would inherit them,
               possibly blocking regular Git operations). The primary
               intended use case is to use named pipes for communication
               (e.g.  **\\.\pipe\my-git-stdin-123**).
    
               Two special values are supported: **off** will simply close the
               corresponding standard handle, and if **GIT_REDIRECT_STDERR** is
               **2** >&1, standard error will be redirected to the same handle as
               standard output.
    
           **GIT_PRINT_SHA1_ELLIPSIS**(deprecated)
               If set to **yes** , print an ellipsis following an (abbreviated)
               SHA-1 value. This affects indications of detached HEADs (‐
               git-checkout(1)) and the raw diff output (git-diff(1)).
               Printing an ellipsis in the cases mentioned is no longer
               considered adequate and support for it is likely to be removed
               in the foreseeable future (along with the variable).
    
           **GIT_ADVICE**
               If set to **0** , then disable all advice messages. These messages
               are intended to provide hints to human users that may help
               them get out of problematic situations or take advantage of
               new features. Users can disable individual messages using the
               **advice.*** config keys. These messages may be disruptive to
               tools that execute Git processes, so this variable is
               available to disable the messages. (The **--no-advice** global
               option is also available, but old Git versions may fail when
               this option is not understood. The environment variable will
               be ignored by Git versions that do not understand it.)
    


## DISCUSSION



           More detail on the following is available from the **Git concepts**
           **chapter of the user-manual******[3] andgitcore-tutorial(7).
    
           A Git project normally consists of a working directory with a
           ".git" subdirectory at the top level. The .git directory contains,
           among other things, a compressed object database representing the
           complete history of the project, an "index" file which links that
           history to the current contents of the working tree, and named
           pointers into that history such as tags and branch heads.
    
           The object database contains objects of three main types: blobs,
           which hold file data; trees, which point to blobs and other trees
           to build up directory hierarchies; and commits, which each
           reference a single tree and some number of parent commits.
    
           The commit, equivalent to what other systems call a "changeset" or
           "version", represents a step in the project’s history, and each
           parent represents an immediately preceding step. Commits with more
           than one parent represent merges of independent lines of
           development.
    
           All objects are named by the SHA-1 hash of their contents,
           normally written as a string of 40 hex digits. Such names are
           globally unique. The entire history leading up to a commit can be
           vouched for by signing just that commit. A fourth object type, the
           tag, is provided for this purpose.
    
           When first created, objects are stored in individual files, but
           for efficiency may later be compressed together into "pack files".
    
           Named pointers called refs mark interesting points in history. A
           ref may contain the SHA-1 name of an object or the name of another
           ref (the latter is called a "symbolic ref"). Refs with names
           beginning **refs/head/** contain the SHA-1 name of the most recent
           commit (or "head") of a branch under development. SHA-1 names of
           tags of interest are stored under **refs/tags/**. A symbolic ref named
           **HEAD** contains the name of the currently checked-out branch.
    
           The index file is initialized with a list of all paths and, for
           each path, a blob object and a set of attributes. The blob object
           represents the contents of the file as of the head of the current
           branch. The attributes (last modified time, size, etc.) are taken
           from the corresponding file in the working tree. Subsequent
           changes to the working tree can be found by comparing these
           attributes. The index may be updated with new content, and new
           commits may be created from the content stored in the index.
    
           The index is also capable of storing multiple entries (called
           "stages") for a given pathname. These stages are used to hold the
           various unmerged version of a file when a merge is in progress.
    


## SECURITY



           Some configuration options and hook files may cause Git to run
           arbitrary shell commands. Because configuration and hooks are not
           copied using **git clone** , it is generally safe to clone remote
           repositories with untrusted content, inspect them with **git log** ,
           and so on.
    
           However, it is not safe to run Git commands in a **.git** directory
           (or the working tree that surrounds it) when that **.git** directory
           itself comes from an untrusted source. The commands in its config
           and hooks are executed in the usual way.
    
           By default, Git will refuse to run when the repository is owned by
           someone other than the user running the command. See the entry for
           **safe.directory** in git-config(1). While this can help protect you
           in a multi-user environment, note that you can also acquire
           untrusted repositories that are owned by you (for example, if you
           extract a zip file or tarball from an untrusted source). In such
           cases, you’d need to "sanitize" the untrusted repository first.
    
           If you have an untrusted **.git** directory, you should first clone it
           with **git clone --no-local** to obtain a clean copy. Git does
           restrict the set of options and hooks that will be run by
           **upload-pack** , which handles the server side of a clone or fetch,
           but beware that the surface area for attack against **upload-pack** is
           large, so this does carry some risk. The safest thing is to serve
           the repository as an unprivileged user (either via git-daemon(1),
           ssh, or using other tools to change user ids). See the discussion
           in the **SECURITY** section of git-upload-pack(1).
    


## FURTHER DOCUMENTATION



           See the references in the "description" section to get started
           using Git. The following is probably more detail than necessary
           for a first-time user.
    
           The **Git concepts chapter of the user-manual******[3] andgitcore-tutorial(7) both provide introductions to the underlying
           Git architecture.
    
           See gitworkflows(7) for an overview of recommended workflows.
    
           See also the **howto******[4] documents for some useful examples.
    
           The internals are documented in the**Git API documentation******[5].
    
           Users migrating from CVS may also want to readgitcvs-migration(7).
    


## GIT



           Part of the git(1) suite
    


## NOTES



            1. Git User’s Manual
               file:///home/mtk/share/doc/git-doc/user-manual.html
    
            2. Trace2 documentation
               file:///home/mtk/share/doc/git-doc/technical/api-trace2.html
    
            3. Git concepts chapter of the user-manual
               file:///home/mtk/share/doc/git-doc/user-manual.html#git-concepts
    
            4. howto
               file:///home/mtk/share/doc/git-doc/howto-index.html
    
            5. Git API documentation
               file:///home/mtk/share/doc/git-doc/technical/api-index.html
    
            6. git@vger.kernel.org
               mailto:git@vger.kernel.org
    
            7. git-security@googlegroups.com
               mailto:git-security@googlegroups.com
    


* * *