Git Started: Advanced Tips

This tutorial aims to explain Git in a way beginners can understand. This is the third post of the cleverly named series Git Started. In this post, I will share some useful tips for using git on the command line. For a conceptual understanding of Git, please refer to the first post: [Git Started: Introduction]({% post_url 2019-09-21-git-started-introduction %}). For an introduction on git CLI usage, please refer to the second post: [Git Started: Basic Usage]({% post_url 2019-10-10-git-started-basic-usage %}).

Patches

Any change to a versioned file is a patch. Back when the dinosaurs roamed the ARPANET, a patch could be sent by email and applied to the source. However possible today, that is generally not necessary.

With that background, here is your Pro Tip!!!: Git allows to add patches via git add -p.

Whenever I stage my changes, I almost always use git add -p because it forces me to actually see what I did. It is a self code-review before anyone else reviews it, and more often than not it has helped me catch bugs before ever running the code.

Bonus Pro Tip!!!: git diff --staged or git diff --cached will show you the changes already added.

I’ve Made a Mistake

Fixing small mistakes in your last commit is simply adding the (corrected) changes, then amending the commit.

Pro Tip!!!: git commit --amend --no-edit to make amends.

To fix any mistakes in a previous commit, you will have to rebase which translates to modifying that commit and then applying all the patches after it. The easiest way that I like to rebase is interactively: git rebase -i HEAD~10.

Catch Up to Master

Generally when working on a feature branch, you will branch off of master then make a PR to get your changes in. In that time it takes you to write your feature, master can update causing your feature branch to become out of date.

Pro Tip!!!: Catch up to master with git rebase -f -X theirs upstream/master.

When ran from your feature branch, this command will rebase (apply feature branch’s changes) onto upstream/master. It will also automatically resolve conflicts by choosing the changes in upstream/master over your changes.

                     A---B---C topic
                    /
               D---E---F---G master

       From this point, the result of following command:

           git rebase -f -X theirs master

       would be:

                             A'--B'--C' topic
                            /
               D---E---F---G master

Logs

The last tip is for those who need a better visual of Git history (including myself). This is how I always view the Git log.

Pro Tip!!!: git log --graph --decorate --all to view a full graph log of the entire repository history. For Oh My Zsh! users, this is equivalent to the alias glgga.

Bonus Pro Tip!!!: git log -p to show patches changed in each commit and git log -S string to search for commits that have added or deleted “string”. Combine the two for an easy way to search your history!

Conclusion

This concludes the cleverly named Git Started series. Hopefully you learned something new about Git and can confidently use the git CLI.