The .git directory is the core of the Git repository and contains all the data required for version control. 1. It stores key contents such as objects (such as commits, trees, tags), references (such as branches and tag pointers), HEAD's current branch information, index temporary storage area, configuration files, etc. 2. Users usually do not need to manually operate these files, because direct editing may cause the repository to be damaged, such as deleting files, modifying references, or destroying indexes. 3. If there is a problem, you can use gitfsck or gitreflog to fix it. 4. Although .git content should not be changed at will, viewing files such as HEAD, config and logs can help understand the operation of Git. Understanding the structure of .git helps to gain a deep understanding of how Git works.

A three-way merge is a merge method that uses the original version and two modified versions to resolve conflicts more accurately. 1. It is based on three versions: Common ancestor (base version), your changes (local version), and others' changes (remote version). 2. The system compares the two modified versions with the basic version, identify overlapping modifications and marks conflicting areas for manual processing. 3. Compared with two-way comparison, it can better understand the change context, reduce false positives and improve the security of automatic merging. 4. Commonly used in Git branch merge, PullRequest and advanced merge tools. 5. When using it, make sure that the selected basic version is the true common ancestor, and use tools that support three-way merging to ensure accuracy.

TocloneaGitrepository,ensureGitisinstalledbycheckingwithgit--versionandinstallingifneeded.(1)Setupyourusernameandemailusinggitconfig.(2)UsegitclonefollowedbytherepositoryURLtocreatealocalcopy.(3)Forprivaterepos,useSSHwithanaddedkey.(4)Optionallyspeci

Common Git workflows include Gitflow, GitHubFlow and GitLabFlow, each suitable for different development scenarios. Gitflow is suitable for projects with planned release, and is structured management through main, develop, feature, release and hotfix branches; GitHubFlow is centered on a single main branch, emphasizing continuous delivery, and is suitable for small teams or web applications that require frequent deployment; GitLabFlow increases environment awareness based on GitHubFlow, supports multi-environment deployment and uses tags to track production status. Each process has its own advantages and disadvantages, and should be adjusted according to the team size, project type and release frequency when choosing.

.gitignore files are used to specify files or folders that Git should ignore, preventing them from being committed to the repository, thus avoiding unnecessary or sensitive files being traced. Its core functions include: 1. Exclude temporary files generated during development such as node_modules, .env, .log, etc.; 2. Avoid specific files generated by the operating system or editor entering version control; 3. Clean up the compiled products generated by the construction tool such as dist/, build/ directory; 4. Pay attention to syntax such as wildcard characters *, directories ending with /, and ! when setting. If you have submitted the file, you need to manually run gitrm-r--cached. Clear the cache and then resubmit it.

To clear the entire stash list in Git, there are no direct built-in commands, but it can be done in a few steps. First run gitstashlist to view all current stash entries, and then use gitstashdropstash@{n} to delete them one by one, or use gitreflogdelete --expire-unreachable=nowrefs/stash and gitgc-prune=now to force all stashes to be cleared at once. In addition, you can also use the bash loop command whilegitstashlist|grep-q'^stash@';dogitstashdrop;d

Git submodule allows embedding of one Git repository as a subdirectory into another repository, suitable for references to external projects or components without merging their history. Reasons for using submodules include: managing third-party libraries with independent version control, maintaining independent development history for different parts of a project, and sharing code among multiple projects. The working principle of a submodule is: when adding a submodule, Git will record the specific submissions to be used, and the parent project only tracks the changes in the submodule, not the file changes in the submodule; the submodule needs to be initialized and updated after cloning the main repository; the submodule information is stored in the .gitmodules file and .git/config, and the actual file is located in the .git/modules/ path. Applicable scenarios include: Strict control of external dependency versions

Packfile is an efficient mechanism used by Git to package, compress and transfer repository objects. When you execute gitpush, gitfetch or gitclone, what Git actually transmits is the packfile; 1. It is initially generated by loose objects through gitgc or gitrepack commands and stored in the .git/objects/pack/ directory; 2. The packfile not only contains object data, but also records the delta relationship between objects, and achieves rapid search with index file (.idx). 3. This design reduces the transmission volume and improves synchronization efficiency; 4. A large number of small packfiles may affect performance, and can be used through gitgc or git