Git被称为“The Stupid Content Tracker“（简称TCS），这个名称来源于它的创始人Linus Torvalds对它简洁直接的工作方式的描述

Git 被称为 “The Stupid Content Tracker”（简称 TCS），这一称呼反映了它的设计哲学以及创始人的幽默感。以下是对此名称来源及含义的解释：

1. 简单直接的设计理念
   Linus Torvalds 设计 Git 的初衷是为了满足 Linux 内核开发的需求，追求高效、快速和灵活性。他希望工具能够专注于核心功能而不被复杂的附加特性所干扰。“Stupid” 并非贬义词，而是强调了 Git 对于内容跟踪采取的一种极其直白的方式 —— 它不会尝试去理解文件的内容意义，只是单纯记录文件的变化。

2. 关注内容而非形式
   Git 更倾向于把注意力放在数据块上而不是像一些其他版本控制系统那样分析代码结构或者试图解析文本内的语法等高级特征。所以从某种意义上说,Git确实显得有些“愚蠢”,因为它只关心二进制级别的差异对比,对于更高层面上的应用场景不做过多干预.

3. 高效的分布式协作模型
   此外，“Content Tracker”的命名也体现了 Git 分布式架构下强大的内容管理能力。每个开发者都可以拥有完整的本地副本，包括所有的历史记录，并且可以独立完成各种操作如提交更改、创建分支等等，最后再与其他远程仓库同步更新状态即可。
   Git被称为"The Stupid Content Tracker"（简称TCS），这个名称来源于它的创始人Linus Torvalds对它简洁直接的工作方式的描述。尽管名字听起来有些贬义，但它实际上是在强调Git的直截了当和不添加复杂性的设计理念。Git的核心思想是让开发者能够轻松地管理文件的历史记录，即使是最小的改动也能被精确追踪。它的分布式特性使得每个开发者都有完整的项目副本，这样即便在网络不稳定时也能继续工作，而且合并过程相对简单。

Git不直接被称为"TCS"，但它的全名"Git"（GNU Interface Tool）可以与"Transportation Control System"（交通控制系统）的概念形成关联。这里的"TCS"可能是用来指代Git在软件开发中的作用，特别是在opentCS这样的交通运输自动化项目中。作为版本控制系统，Git帮助管理和跟踪代码变更，这对于任何控制系统的软件开发流程至关重要。

相关问题–:

1. Git在opentCS中的具体应用是什么？
2. 在其他领域，Git如何支持TCS类型的项目管理？
3. 如何通过Git进行代码审查以保证TCS系统的安全性？
   Git --local-branching-on-the-cheap
   Git确实因其创始人Linus Torvalds所赋予的绰号"The Stupid Content Tracker"而闻名。这个名字反映了Linus对于Git设计初衷的理念，即保持简单易用，专注于追踪文件内容的变化，而不是试图变得过于智能或复杂。尽管这个名称可能听起来贬低，但实际上是对其功能直接和不加掩饰的特点的一种赞美，因为这使得非技术背景的人也能轻松上手。

(1) Linus在其项目介绍时常常强调这一点，他认为Git的核心价值在于其直观的命令行接口和对版本控制基础操作的支持，如添加、提交和分支管理，这些操作对于开发者来说非常重要。
Git被称为"TCS"（理论计算机科学）的原因并不是因为它源于这个领域，而是因为它的创始人Linus Torvalds是一位计算机科学家，他在创建Git时受到了理论计算机科学原则的影响，特别是版本控制系统的设计原理。TCS通常指的是研究计算理论和算法设计的学科，而Git的设计展示了这些概念在实际软件开发工具中的应用。
除了Linus Torvalds（Linux内核的创始人）之外，Git的主要开发者还包括Jeff King、Junio C Hamano (也被称为gitster) 和 Tim Pope等人。他们在项目早期和后续版本的改进中发挥了关键作用。

Git协作机制对软件开发的重要性主要体现在以下几个方面：

1. 版本控制: Git作为分布式版本控制系统，使得每个开发人员都可以拥有完整的代码副本，这允许他们独立工作并在本地进行提交，避免了中央服务器的压力。

2. 分支管理: Git支持快速创建和切换分支，开发者可以轻松地在不同功能或修复任务上并行工作，提高了团队的生产力。

3. 冲突解决: 当多人修改同一部分代码时，Git的合并工具能够帮助识别和解决潜在的冲突，保持代码的一致性。

4. 记录与追踪: 每次提交都有详细的元数据，包括作者、时间、消息和改动，方便团队成员了解代码历史，进行审计和回滚。

5. 远程协作: Git支持通过远程仓库（如GitHub、GitLab）与其他团队成员共享代码，即使不在同一地理位置也能高效合作。

因此，Git协作机制极大地促进了团队间的协同开发和项目管理。
Git的简洁直接的工作方式主要体现在以下几个方面：
一、核心功能的直观性
Git的核心功能包括版本控制、分支管理、合并等，这些功能在Git中都被设计得非常直观和易于理解。
版本控制：Git能够精确地追踪文件的每一次变更，开发者可以轻松地回溯到之前的版本，解决bug或恢复丢失的代码。这一过程通过简单的命令（如git commit、git log等）即可完成，无需复杂的配置或学习。
分支管理：Git支持快速创建和切换分支，允许开发者在不影响主代码库的情况下进行并行开发或实验。分支的创建和合并操作也非常简单，只需使用git branch、git checkout、git merge等命令即可。
二、命令行的易用性
Git通过命令行界面提供了一系列简洁明了的命令，使得开发者能够高效地管理代码库。
命令的简洁性：Git的命令通常都很短，而且易于记忆。例如，git add用于将文件添加到暂存区，git commit用于提交更改，git push用于将更改推送到远程仓库等。
命令的输出：Git命令的输出也非常直观，通常包含必要的信息，而且易于理解。例如，git status命令会显示当前工作目录的状态，包括哪些文件已被修改、哪些文件已被暂存等。
三、工作流程的清晰性
Git的工作流程非常清晰，通常包括以下几个步骤：
初始化仓库：使用git init命令创建一个新的Git仓库，或者在现有项目中初始化Git仓库。
添加和提交更改：在工作目录中修改文件后，使用git add命令将更改添加到暂存区，然后使用git commit命令将更改提交到本地仓库。
推送更改到远程仓库：使用git push命令将本地仓库的更改推送到远程仓库，以便与其他团队成员共享。
拉取远程仓库的更改：使用git pull命令从远程仓库拉取最新的更改，并合并到本地仓库中。
四、分布式架构的灵活性
Git采用分布式架构，使得每个开发者都有完整的项目副本。这种架构带来了极大的灵活性：
离线开发：开发者可以在没有网络连接的情况下进行开发，并在连接恢复后将更改推送到远程仓库。
多仓库协作：Git支持同时连接多个远程仓库，方便开发者在不同的项目或分支之间进行协作。
五、专注于核心内容
Git专注于提供版本控制和协作的基本功能，避免添加不必要的复杂性。这使得Git成为了一个高效、可靠的版本控制系统，广泛应用于各种软件开发项目中。
总结：
Git的简洁直接的工作方式体现在其核心功能的直观性、命令行的易用性、工作流程的清晰性、分布式架构的灵活性以及专注于核心内容等方面。这些特点使得Git成为了一个高效、可靠且易于使用的版本控制系统。
Git被称为“The Stupid Content Tracker”（简称TCS）这一名称，确实来源于它的创始人Linus Torvalds对其简洁直接的工作方式的描述。
分析说明：
简洁直接的设计理念：Linus Torvalds在创建Git时，旨在提供一个简单、高效的版本控制系统。他将其描述为“The Stupid Content Tracker”，这里的“stupid”并非贬义，而是强调Git的直截了当，不添加不必要的复杂性。Git的核心思想是让开发者能够轻松地管理文件的历史记录，即使是最小的改动也能被精确追踪。
名称的寓意：
The Stupid Content Tracker：这个名字反映了Linus对于Git设计初衷的理念，即保持简单易用，专注于追踪文件内容的变化，而不是试图变得过于智能或复杂。
简称TCS：尽管Git通常不直接被称为"TCS"，但这个简称有时被用来指代Git在软件开发中的作用，尤其是在某些特定的项目或语境中。
Git的特点：
分布式特性：每个开发者都有完整的项目副本，即使在网络不稳定时也能继续工作，而且合并过程相对简单。
高效性：Git使用快照而非差异的方式记录文件变化，操作速度快，适合处理大型项目。
强大的分支和合并功能：支持快速创建和切换分支，方便开发者并行工作，提高团队的生产力。
总结：
Git被称为“The Stupid Content Tracker”（简称TCS）这一名称，是对其简洁直接、高效实用的工作方式的形象描述。这个名字虽然听起来有些特别，但实际上是对Git功能特点的一种赞美和认可。

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 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

–version

Prints the Git suite version that the git program came from.

–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

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 =

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.

–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.

–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=

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=

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=

Set the Git namespace. See gitnamespaces[7] for more details. Equivalent to setting the GIT_NAMESPACE environment variable.

–super-prefix=

Currently for internal use only. Set a prefix which gives a path from above a repository down to its root. One use is to give submodules context about the superproject that invoked it.

–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. See git-replace[1] for more information.

–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.

–no-optional-locks

Do not perform optional operations that require locks. This is equivalent to setting the GIT_OPTIONAL_LOCKS to 0.

–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)

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-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

gitk[1]

The Git repository browser

git-log[1]

Show commit logs

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]

Initialize and modify the sparse-checkout

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

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-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-count-objects[1]

Count unpacked number of objects and their disk consumption

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]

Show three-way merge without touching index

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

gitweb[1]

Git web interface (web frontend to Git repositories)

git-whatchanged[1]

Show logs with difference each commit introduces

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 creates a blob 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-multi-pack-index[1]

Write and verify multi-pack-indexes

git-mktag[1]

Creates a tag object

git-mktree[1]

Build a tree-object from ls-tree formatted text

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-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 content or type and size information for 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-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-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-parse-remote[1]

Routines to help parsing remote repository access parameters

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-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

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

Indicates the object name for any type of object.

Indicates a blob object name.

Indicates a tree object name.

Indicates a commit object name.

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>.

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>.

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

Indicates a filename - almost always relative to the root of the tree structure GIT_INDEX_FILE describes.

Symbolic Identifiers

Any Git command accepting any can also use the following symbolic notation:

HEAD

indicates the head of the current branch.

a valid tag name (i.e. a refs/tags/<tag> reference).

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 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 a foreign front-end.

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_INDEX_VERSION

This environment variable allows the specification of an index version for new repositories. 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 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 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, instead of the diff invocation described above. 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_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_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_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 environment variable is set to 0, git will not prompt on the terminal (e.g., when asking for HTTP authentication).

GIT_CONFIG_NOSYSTEM

Whether to skip reading settings from the system-wide $(prefix)/etc/gitconfig file. This 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 temporarily to avoid using a buggy /etc/gitconfig file while waiting for someone with sufficient permissions to fix it.

GIT_FLUSH

If this environment variable is set to "1", 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 "0", 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_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. This option overrides setting the GIT_CURL_VERBOSE environment variable. 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 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 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 for full details.

GIT_REDACT_COOKIES

This can be set to a comma-separated list of strings. When a curl trace is enabled (see GIT_TRACE_CURL above), whenever a "Cookies:" header sent by the client is dumped, values of cookies whose key is in that list (case-sensitive) are redacted.

GIT_LITERAL_PATHSPECS

Setting this variable to 1 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 variable to 1 will cause Git to treat all pathspecs as glob patterns (aka "glob" magic).

GIT_NOGLOB_PATHSPECS

Setting this variable to 1 will cause Git to treat all pathspecs as literal (aka "literal" magic).

GIT_ICASE_PATHSPECS

Setting this variable to 1 will cause Git to treat all pathspecs as case-insensitive.

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 set to 1, include broken or badly named refs when iterating over lists of refs. In a normal, non-corrupted repository, this does nothing. However, enabling it may help git to detect and abort some operations in the presence of broken refs. Git sets this variable automatically when performing destructive operations like git-prune[1]. You should not need to set it yourself unless you want to be paranoid about making sure an operation has touched every ref (e.g., because you are cloning a repository to make a backup).

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). In other words, any protocol not mentioned will be disallowed (i.e., this is a whitelist, not a blacklist). See the description of protocol.allow in git-config[1] for more details.

GIT_PROTOCOL_FROM_USER

Set to 0 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.

GIT_OPTIONAL_LOCKS

If set to 0, 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).

Discussion

More detail on the following is available from the Git concepts chapter of the user-manual and gitcore-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. Refs with names beginning ref/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 ref/tags/. A special 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.
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 and gitcore-tutorial[7] both provide introductions to the underlying Git architecture.

See gitworkflows[7] for an overview of recommended workflows.

See also the howto documents for some useful examples.

The internals are documented in the Git API documentation.

Users migrating from CVS may also want to read gitcvs-migration[7].
Authors

Git was started by Linus Torvalds, and is currently maintained by Junio C Hamano. Numerous contributions have come from the Git mailing list git@vger.kernel.org. http://www.openhub.net/p/git/contributors/summary gives you a more complete list of contributors.

If you have a clone of git.git itself, the output of git-shortlog[1] and git-blame[1] can show you the authors for specific parts of the project.
Reporting Bugs

Report bugs to the Git mailing list git@vger.kernel.org where the development and maintenance is primarily done. You do not have to be subscribed to the list to send a message there. See the list archive at https://lore.kernel.org/git for previous bug reports and other discussions.

Issues which are security relevant should be disclosed privately to the Git Security mailing list git-security@googlegroups.com.
SEE ALSO

gittutorial[7], gittutorial-2[7], giteveryday[7], gitcvs-migration[7], gitglossary[7], gitcore-tutorial[7], gitcli[7], The Git User’s Manual, gitworkflows[7]

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Version 2.26.1 ▾
git last updated in 2.26.1
NAME

git - the stupid content tracker
SYNOPSIS

git [–version] [–help] [-C ] [-c =]
[–exec-path[= ]] [–html-path] [–man-path] [–info-path]
[-p|–paginate|-P|–no-pager] [–no-replace-objects] [–bare]
[–git-dir= ] [–work-tree= ] [–namespace=]
[–super-prefix= ]
[]