Git concepts

Concepts are more important than commands. I don’t try to memorize all commands, I prefer making aliases and learning how Git works.

3 Trees

1. the working directory: the files and directories you modify
2. the index: the changes you stage with a git add for the next git commit
3. the HEAD: a reference that points to the last commit of the current branch and moves when you switch to another branch

Local vs. Remote

The local repository is your machine. You use the remote repository to host your project, for example, on GitHub, GitLab, Bitbucket, etc. Each member of the team work on his local repository and then pushes the modifications to the remote repository when it's done.

Clone, status, pull and push

• git clone is the first command you learn. It copies a remote repository wherever you want if you have access.
• git status allows you to know the current status. Use it as much as you like.
• git pull incorporates changes from a remote repository into the current branch whereas git push updates remote refs using local refs.

Branches

The default branch is main or master. You can create new branches to safely diverge from the main branch. When you have finished, you can merge your new branch in the main branch.

Tags

Tags are versions for a particular branch at a moment in time. Fork It's the act of copying a repository to use it for your own purpose, safely experiment with it or contributing.

Merging vs. rebasing

It's the same purpose: incorporating modifications from one side to another. Merging is safer as it remembers the whole history but it's verbose. Rebasing is cleaner for the history but a bit more risky because it flattens changes as a linear series.

Advanced commands

Use command lines for relatively complex operations. I strongly recommend you use them as aliases. Don’t waste your time memorizing:

Amending a bad commit (BEFORE git push)

git add {file} && git commit --amend and if you don't need to modify the commit message, you can do git add {file} && git commit --amend --no-edit.

Stage and unstage only some modifications in a file

git add -p {file} and git reset -p {file}

Grab modifications from another branch without merging or rebasing

git cherry-pick {commit_sha}

Unstage all modifications in one command (~ unadd)

git reset HEAD

Change remote destination

Don't do git remote rm origin && git remote add origin {URL}. Instead run git remote set-url origin {URL}.

List ignored files

git ls-files --others -i --exclude-standard

Merge all modifications but squash them in one commit

git merge --squash {branch} && git commit

GUI clients

Be efficient, don’t waste your energy typing the same command over and over. GUI clients make sense for simple operations such as cloning, pulling/pushing modifications, and creating new branches.

Besides, it’s not uncommon to get conflicts when merging branches, and you should not handle conflicts without a graphical interface.

GitKraken

This client is simply beautiful. Download latest version of GitKraken

SmartGit

This client is efficient. Download latest version of SmartGit

Submodules

Submodules allow for including other git repositories in your repository as references. When you add submodules, it creates a config file called .gitmodules at the root of your project.

Adding a submodule

git submodule add {submodule_address} && git add {submodule_folder_path} && git commit

Cloning a git project with submodules

Nothing to do. The git clone command already grabs them, but don't forget git submodule update --init --recursive the first time to initialize all repositories locally.

How to update submodules

You can run git submodule update --remote --recursive

How to delete a submodule

Don't do it manually! Instead, run: git submodule deinit {submodule} && git rm {submodule_folder_path} && git commit

Configurations

Git works with a cascade of configuration files. You can define global configurations and override them locally for a particular project or a group of folders.

Global configuration

You can either edit ~/.gitconfig or run: git config --global --edit. You can also define specific git config per each project and folder. It will override the global config. Global list of ignored files and directories You can edit ~/.gitignore_global. You can also define specific .gitignore per each project and folder. It will override the global gitignore.

Git aliases

Aliases are custom shortcuts for git commands. You can edit ~/.gitconfig or run: git config --global --edit, or even run something similar to git config --global alias.st status.

Use ohmyzsh and its git plugins

You can add the git plugin to your config. You'll get excellent shortcuts and aliases.