Git Practical Beginner's Guide

Strategy

GitFlow is a popular git flow strategy. It is a solid start point and can work with CI/CD flows well.

Source: https://datasift.github.io/gitflow/IntroducingGitFlow.html

Theory

Stages

Indexed -> Staged -> Committed -> Pushed or Pulled to remote

Concept: HEAD

HEAD means the current branch. To check where the HEAD is point, you can use the following command.

Unix style command

cat .git/HEAD

OR

Windows style command

type .git/HEAD

Scenarios

Get the latest code from an existing remote branch

The fetch command is for getting the latest of repo’s branch structure. For example, if your colleagues have commited and pushed new branches.

git fetch
git switch "target-branch"
git pull

Even better, you can do the following.

git pull origin source-branch-name
git pull origin master #for example, do this on the target branch

However, I got burnt with the following command. Because it didn’t prompt for conflicts, and left a lot of rubbish in my code base.

git merge origin source-branch-name

Create new branch

git switch -c "feature/[feature-name]"

The git checkout commend is retiring.

git checkout -b "feature/[feature-name]"

Undo indexed changes

git clean
git clean -df #remove untracked directories and files.

Undo staged changes

git checkout -- .

Reset - Undo commited changes with reset

The following command set is for undo the latest commit and it will also keep the change at your local repo unstaged.

git add .
git commit -m "yolo"
git push 
git reset --soft HEAD~1
git commit -m "maybe not"
git push 

Rebase

The following command will go to the head of the origin/main branch. Then apply all commits from the “feature/yolo” branch on the top.

git switch feature/yolo
git rebase origin/main

WorkTree

This is a very useful command. It allows you to have multiple branches available locally in parallel. So you can multitask or compare code in different branches.

git workfree add [local file path] [git branch name]

git worktree add "../yolo" feature/yolo
git worktree remove feature/yolo

Rename your branch

git checkout <old_name>
git branch -m <new_name>
git push origin -u <new_name>
git push origin --delete <old_name>

Reference(s)

https://linuxize.com/post/how-to-rename-local-and-remote-git-branch/

Revert a commit already pushed to a remote repository

“People generally avoid history rewiriting, for a good reason: it will fundamentally diverge your repository from anyone who cloned or forked it. People cannot just pull your rewritten history as usual. If they have local changes, they have to do some work to get in sync again; work which requires a bit more knowledge on how Git works to do it properly.”

Reference(s)

https://christoph.ruegg.name/blog/git-howto-revert-a-commit-already-pushed-to-a-remote-reposit.html

tag

Deployment https://stackoverflow.com/questions/18216991/create-a-tag-in-a-github-repository

stash

Scenarios

You are working on a feature branch and your team lead asked your to fix a bug with urgency. So you need to stash you current work and switch context.

# your are working on new features on branch A
# Save WIP changes
git stash
git swith bugfixes/branch-b
# fix bugs in the branch b
git stash pop

Scenario: Stash your work with meaningful comment.

I recommend stage this way over the default git stash

git stash save "remove semi-colon from schema"
git stash list
git stash pop stash@{2}

Other useful git stash parameters

git stash save --keep-index #All changes already added to the index (staged) are left intact
git stash save --keep-index --include-untracked
git stash --all #stash untracked files and ignored files.
git stash drop

Reference(s)

https://opensource.com/article/21/4/git-stash

switch vs checkout

git switch “branch-name” = git checkout “branch-name”

git restore “path-to-a-file” = git checkout “path-to-a-file”

git switch command parameters

    -c, --create <branch> #create and switch to a new branch
    -m, --merge #perform a 3-way merge with the new branch

push

The following three commands are doing the same thing. the “-u” parameter name stands for upstream.

git push -u origin feature/yolo

git push -u origin

git push

remote prune

Scenario: remove the local branches that are not on the remote any more.

git branch -vv #Check local remote branches mapping
git branch -r #List all remote branches
git remote prune origin

Scenario: delete all local branches that are already merged into master

git branch --merged main | grep -v '^[ *]*main$' | xargs git branch -d

Reference(s)

https://stackoverflow.com/questions/13064613/how-to-prune-local-tracking-branches-that-do-not-exist-on-remote-anymore

Tools

Fork

A light weight tool and great for visualization.

Pretty Prompt

How to setup

Please check out this brilliant article from almighty Scott Hanselman.

Prompt status abbreviation explained

The local branch is behind

The local branch is ahead

The merge conflict

Committed and pushed

PoshGit

I couldn’t say better than Phil Haack. So here is a link to his PoshGit blog post.

References

Sources

What is Git HEAD? https://stackoverflow.com/questions/10228760/how-do-i-fix-a-git-detached-head https://stackoverflow.com/questions/2304087/what-is-head-in-git

How to check current HEAD? https://stackoverflow.com/questions/25879039/cat-git-head-command-in-windows

What is the difference between soft and hard reset? https://stackoverflow.com/questions/3528245/whats-the-difference-between-git-reset-mixed-soft-and-hard/3528483#3528483