In the world of software development, Git is a vital tool that aids in version control and collaborative work. This glossary aims to provide an in-depth understanding of the various terminologies associated with Git. The glossary is tailored to meet the needs of software engineers, providing comprehensive explanations, historical context, use cases, and specific examples where relevant.
Git, as a distributed version control system, has a unique set of terminologies that can be complex and confusing, especially for beginners. This glossary seeks to demystify these terms and provide a clear understanding of their usage and importance in the Git ecosystem.
Definition of Git
Git is a distributed version control system developed by Linus Torvalds, the creator of the Linux operating system. It was designed to handle everything from small to very large projects with speed and efficiency. Git is easy to learn and has a tiny footprint with lightning-fast performance.
It outclasses SCM tools like Subversion, CVS, Perforce, and ClearCase with features like cheap local branching, convenient staging areas, and multiple workflows. In Git, every developer's working directory is a full-fledged repository with complete history and full version-tracking abilities, independent of network access or a central server.
Origin of Git
Git was created by Linus Torvalds in 2005 for development of the Linux kernel, with other kernel developers contributing to its initial development. Its current maintainer since 2005 is Junio Hamano.
The name "Git" was given by Linus Torvalds when he wrote the very first version. He described the tool as "the stupid content tracker" and the name as (depending on your mood).
Key Git Terminologies
Understanding Git requires a grasp of its key terminologies. These terms form the basis of Git's functionality and are crucial for effective usage of the tool.
Here, we will delve into some of the most commonly used Git terminologies, providing clear definitions, explanations, and examples of each.
Repository
In Git, a repository (or "repo" for short) is a digital directory or storage space where your project lives. It can contain all of the project files, and also stores each file's revision history. Repositories can have multiple collaborators and can be either public or private.
A repository is like a project's folder. Each project has its own repo, and you can access it with a unique URL. But unlike a folder on your computer, a Git repository also records all changes and the entire history of the project.
Commit
A commit, or "revision", is an individual change to a file (or set of files). It's like when you save a file, except with Git, every time you save it creates a unique ID (a.k.a. the "SHA" or "hash") that allows you to keep record of what changes were made when and by who. Commits usually contain a commit message which is a brief description of what changes were made.
When you make a commit to save your work, Git creates a unique ID (a.k.a. the "SHA" or "hash") that allows you to keep record of the specific changes associated with each commit. This is also important for collaborating with others, as it allows you to see exactly what changes have been made and by whom.
Branch
A branch is a parallel version of a repository. It is contained within the repository, but does not affect the primary or master branch allowing you to work freely without disrupting the "live" version. When you've made the changes you want to make, you can merge your branch back into the master branch to publish your changes.
Branching is a core concept in Git, and the entire Git flow is based upon it. It's a way to propose changes you want to make. For example, if you want to add a new page to your website you can create a new branch just for that page without affecting the main part of the project. Once you're done with the page, you can merge your changes from your branch into the master branch. When you create a new branch, Git keeps track of which commit your branch 'branched' off of, so it knows the history behind all the files.
Git Commands
Git commands are a set of instructions that perform a specific operation or task in the Git environment. These commands are used to create repositories, create and switch branches, commit changes, push code to remote repositories, and more.
Understanding these commands is crucial to effectively using Git. Here, we will delve into some of the most commonly used Git commands, providing clear definitions, explanations, and examples of each.
git init
The 'git init' command is used to initialize a new Git repository. It is the first command that you'll use when starting a new project. The command creates a new .git subdirectory in the current working directory. This .git subdirectory contains all the necessary metadata for the new repository.
For example, if you're starting a new project in a directory named 'my_project', you would navigate to this directory in your terminal and then run the 'git init' command. This would create a new Git repository in the 'my_project' directory.
git clone
The 'git clone' command is used to create a copy of an existing Git repository. This is typically used to download a repository from a remote server to your local machine. The command takes the URL of the repository as a parameter.
For example, if you wanted to download a repository located at 'https://github.com/user/repo', you would run the command 'git clone https://github.com/user/repo'. This would create a new directory in your current working directory named 'repo', and would download the repository into this directory.
git add
The 'git add' command is used to stage changes for the next commit. When you make changes to your project, Git recognizes that the files have changed, but it doesn't include these changes in the next commit unless you tell it to. The 'git add' command is how you tell Git to include the changes in the next commit.
For example, if you've made changes to a file named 'file1.txt', you would run the command 'git add file1.txt' to stage these changes. You can also use the command 'git add .' to stage all changes in the repository.
Git Workflow
The Git workflow is a set of rules that dictate how changes are applied to a Git repository. It includes steps like branching, committing changes, and merging branches. The workflow ensures that the repository remains organized and that changes are applied in a controlled manner.
Understanding the Git workflow is crucial for effective collaboration and version control. Here, we will delve into the standard Git workflow, providing a clear explanation and examples of each step.
Creating a Branch
The first step in the Git workflow is to create a new branch. This is done using the 'git branch' command followed by the name of the new branch. For example, 'git branch new_feature' would create a new branch named 'new_feature'.
Once the branch is created, you can switch to it using the 'git checkout' command followed by the name of the branch. For example, 'git checkout new_feature' would switch to the 'new_feature' branch. You can also create and switch to a new branch in one command using 'git checkout -b new_feature'.
Making Changes
Once you've switched to your new branch, you can start making changes to your project. These changes can be anything from adding new features to fixing bugs. Once you've made your changes, you can view them using the 'git status' command. This will show you all of the files that have been modified since the last commit.
After reviewing your changes, you can stage them for the next commit using the 'git add' command. For example, 'git add .' would stage all changes in the repository. Once your changes are staged, you can commit them using the 'git commit' command followed by a message describing the changes. For example, 'git commit -m "Added new feature"' would commit the changes with the message "Added new feature".
Merging Changes
Once your changes have been committed, you can merge them into the master branch. This is done using the 'git merge' command followed by the name of the branch that you want to merge. For example, 'git merge new_feature' would merge the 'new_feature' branch into the current branch.
Before you can merge your changes, you need to switch back to the branch that you want to merge into. This is typically the master branch. You can switch to the master branch using the 'git checkout master' command. Once you're on the master branch, you can merge your changes using the 'git merge' command.
Conclusion
Git is a powerful tool for version control and collaboration in software development. Understanding the key terminologies and commands associated with Git is crucial for effective usage of the tool. This glossary provides a comprehensive overview of these terminologies and commands, and serves as a valuable resource for software engineers.
Whether you're a beginner just getting started with Git, or an experienced developer looking to brush up on your Git knowledge, this glossary has something for you. By understanding and applying the concepts explained in this glossary, you can improve your efficiency and productivity in your software development projects.