Day-10:Advance Git & GitHub for DevOps Engineers

Introduction

Hey DevOps enthusiasts! Today, we're diving into the cool stuff in Git and GitHub. Get ready to learn advanced tricks like Reverting, Reset, Rebase, and Merge, and why Branches are a big deal. We're keeping it interactive with hands-on tasks – stuck? Solutions are at your service. No more delays, let's make Git and GitHub a breeze! 🚀

GIT Branching

What is Git Branch?

A branch in Git is the line of development. In the normal scenario, we have a default branch ("master" or "main" ) and then we have other sub branches called the feature branch.

The Feature branch are used to push code that contains changes from the local repository to the remote repository without disturbing the line of development i.e. the default branch.

These sub branches can later on get merged to the default branch if it meets the requirements of the project.

Naming Convention of Branches:

A branch can be named on the purpose they solve. Here's a table explaining the ideal naming convention that should be followed:

Commands:

1. To Check the current branch

     git branch
   

2. To Create a branch

     git branch <name_of_branch>
   

3. To Checkout and Create a branch at the same time

     git checkout -b <name_of_branch>
   

4. To list all branches

     git branch -a
   

5. To Delete a branch

     git checkout -d <name_of_branch>
   

Git Revert and Reset

What is Git Revert?

Git Revert is the command that is used for undoing changes to a repository's commit history.

Git Reverts creates a new commit in which the changes made in the previous commit are reverted or Undone. By doing this, it preserves the commit history and users can access to the past commit if needed.

NOTE: It does not delete the commit.

Commands:

1. To Revert a change

     git revert <Hash_code_of_the_commit>
   

2. To Revert the previous commit

     git revert HEAD
   

What is Git Reset?

This is a similar command as compared to git revert but the catch here is that it creates a commit undoing the changes and DELETES the commit which needs to be undone.

There are two types of Resetting:

• --soft : It resets the commit but still we can have the access to the commit in the git history.

• --hard : It resets the commit and deletes it. This way we don't have any access to the history and the commit cannot be accessed.

Commands:

git reset --soft HEAD~n 
git reser --hard HEAD~n

Where n is the number of commits respectively from the head we want to reset.

Git Rebase and Merge

What is git Rebase?

Rebasing is the process of moving or combining a sequence of commits to a new base commit. Rebasing is most useful and easily visualized in the context of a feature branching workflow. The general process can be visualized as the following:

From the above we can conclude, rebasing is changing the base of your branch from one commit to another making it appear as if you'd created your branch from a different commit.

Git accomplishes this by creating new commits and applying them to the specified base.

NOTE: It's very important to understand that even though the branch looks the same, it's composed of entirely new commits.

Read more about Rebasing, Here.

What is Git Merge?

Git merge is a command used to merge two or more branches into the Main or Default branch.

Say we have a new branch feature that is based off the main branch. We now want to merge this feature branch into main.

Calling the git merge command will merge the specified branch feature into the main branch.

Read more, Here.

Commands:

git merge

Hands On Practice

Task 1:

• Navigate to the Devops directory and create a new branch called dev:

    git checkout -b dev && git branch
  

  

  

  

  Add new commit indevbranch after adding below mentioned content in Devops/Git/version01.txt: While writing the file make sure you write these lines

• 1st line>> This is the bug fix in development branch

    echo "This is the bug fix in development branch" >> version01.txt
  

  

• 2nd line>> This is gadbad code

    echo "This is gadbad code" >> version01.txt
  

  

• Commit this with message “ Added feature3 in development branch

•   git add version01.txt
  

git commit -m "Added feature3 in development branch"

• 3rd line>> This feature will gadbad everything from now.

echo "This feature will gadbad everything from now." >> version01.txt

• Commit with message “Added feature4 in development branch"

  

  

  Restoring the file to a previous version where the content should be “This is the bug fix in development branch”. We'll be using git reset command followed by --hard flag.

•   git reset --hard ec25c68
  

git push origin dev --force

Task 2:

• Create and switch to a new branch (e.g., feature_branch):

    git checkout -b feature_branch
  

    echo "created a new branch and added some changes in this feature_branch" > feature_branch.txt
  

  

  • Add changes to the dev branch and merge it into the main branch:

      git switch dev
      echo "Hello from TWS" >>version01.txt
      cat version01.txt
      git add version01.txt
      git commit -m "Make some changes"
    

    

      git switch main
    

      git merge dev
    

    

    Practicegit rebase:

    • Create and switch to a new branch (e.g., feature_branch2):

        git checkout -b feature_branch2
      

      

      • Make some changes in this branch, then rebase it onto the dev branch:

        

          echo "created a new branch and added some changes in this feature_branch2" > feature_branch2.txt
        

          git add feature_branch2.txt
          git commit -m "Added feature_branch2"
        

        

          git rebase dev
        

        

        

        This is the changes when you do rebase ⬆️

Conclusion

So here comes the end of this blog. In summary we covered the major concepts of branch, naming convention of branches, commands and also understood the differences between Git Revert, Git Reset and Git Rebase and Git Merge. Along with that the hands on practice section acted as a cherry on the cake making our learning even more fun and robust.

Happy Learning

Thanks For Reading!