Git Tutorial

A basic tutorial on using git for version control, focusing on git native commands. There are some easy-to-use tools that can be an assistance, such as Git Graph (vscode extension) and Source Control (vscode built in tool).

Some reference: Official Tutorial, Docs Tutorial, Video Tutorial

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1. Create and Submit

1.1 Clone a remote repo to local

git clone https://github.com/Shihao-Feng-98/GitTutorial.git

1.2 Initialize the local repo

git config --global user.email "[email protected]"
git config --global user.name "Your Name"

Note: Up to date, you can coding locally.

1.3 Put the current files into Stage

git add . # add all modified files
git add file_name # add specific file

1.4 Submit the current contents of Stage to Branch

git commit -m "some descriptions of submission" # add some descriptions

1.5 Push to remote (Github or Gitlab)

git push origin main # push to the corresponding remote branch, e.g. main

Note: You can add, commit, or push multiple times as you need.

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2. Version Control

2.1 Version rollback

If you want to rollback to the previous version, run

git log # find the commit_id that you want to rollback
git reset --hard commit_id

Now, if you want to rollback to the future version of the current version, run

git reflog # show the command you have been used, find the commit_id here
git reset --hard commit_id

2.2 Undo changes

If you want to undo the changes on the working directory, run

git checkout -- file_name

If you want to undo the changes that have been add to stage, run

git reset HEAD file_name
git checkout -- file_name

If you want to undo the canges that have been commit, run

git reset --hard commit_id
git reset HEAD file_name
git checkout -- file_name

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3. Use Feature branch

When you developing a new feature in a project, the following process should be followed.

3.1 Create a new branch

git checkout dev # switch to desired parent branch, e.g. dev
git branch dev/feat_a # create a branch, e.g. dev/feat_a
git checkout dev/feat_a # switch to new branch, e.g. dev/feat_a

3.2 Follow 1.3, 1.4, and 1.5

Note: The "dev/feat_a" branch would created on the remote after implementing 1.5.

3.3 Use pull request

When you cooperate with others, a pull request should be submitted. Before merging your branch, you should modify your code after review.

3.4 Deal with conflict

When new changes have been applied to the dev branch, the current merge may fail. Sometimes conflicts should be resolved before the current merge.
TODO: conflict ref

3.5 Merge to desired branch

git checkout dev # switch to desired branch
git merge dev/feat_a # merge feature branch to desired branch

3.6 Delete the old branch

git branch -d dev/feat_a # delete the local branch
git push origin --delete dev/feat_a # delete the remote branch

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4 Use Bug branch

If there is a bug needs to be fixed when you developing a new feature in a project, the following process should be followed.

4.1 Stash the current code

git stash # save the current code

4.2 Create new branch and fix the bug

Please follow 3.1.

4.3 Recovery the previous code

git stash pop # recovery code and delete the stash

4.4 Fix the same bug on current branch

git log # find the commit_id for bug fixing
git cherry-pick commit_id

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5 Some Useful Skills

5.1 Get information

git log # list the commit history

git status # check the status of the current local branch

git remote show origin # check the infomation of remote branch

git branch # list local branch
git branch -r # list remote branch
git branch -a # list all branch

git tag # list tag
git show tag_name # check the infomation of the current tag 

5.2 Combine commits

During development, you would add many commits, but you should combine them into one commit before Pull request to keep it clear.

Use git reset --soft:

git log -5 # show last 5 commits
git reset --soft commit_id # restore files from repo to cache without changing the local work area
git add -u # add tracked files
git commit -m "new description"
git push --force

Use git rebase:

git log -5
git rebase -i HEAD~5 # combine last 5 commits into one commit
git push --force

Notes:

• Run git rebase -i HEAD~5 would enter a editor, change the reserved commit as pick, change the discarded commit as fixup.
• git rebase would create a new branch. If you make a mistake, you can git checkout to the previous branch and git rebase again.