The three States of Git

We’ve created Our First Commit with Git following our steps, but now we going to learn what really happened.

Git has three basic states, which are: committed, modified and staged. After you commit changes and you have your modifications ready, you can relax then because all your changes are safe in Git’s timeline, when the state is modified Git recognizes a change in the files but they aren’t committed and staged means the actual modifications of the files are in the queue but they are not committed.

Note: by actual modifications I mean the modifications you did to the file(s) before adding them to the queue, if you don’t tell Git you want to submit any new changes you do after the first commit, Git is going to submit the file(s) “as it was/as they were” when you told Git to add the file(s) to the queue in the first place.

Let’s start with the fun part, we are going to use git status, which can be familiar to some of you because we used it in the last part of this course.

On branch master
nothing to commit, working tree clean

As you can see, the output we get is really straight forward, the working tree is clean, in other words, there’s no file(s) to be committed. Why is this happening to me? Because the only file we have in our repository didn’t suffer any changes so… let’s sort this out. :P

Okay, remember index.html? We are going to modify it, just a simple change, adding the following snippet just before the<h1>.

<p>Would you like to get ninja level in Git?</p>

What about another git status?

On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)
        modified:   index.html
no changes added to commit (use "git add" and/or "git commit -a")

Knowledge is priceless, right? Now Changes not staged for commit sounds a bit better for us now, but we didn’t told Git we want to commit the changes, let’s do it with git add index.html.

On branch master
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)
        modified:   index.html

We have the actual version staged and ready for commit, what about adding some spice to our HTML? Just an extension of the last line we just added.

<p>Would you like to get ninja level in Git? Stay tuned to our course!</p>

As you can see we just added Stay tuned to our course! which would be the pride of all the Marketing Experts to be honest but what happens now with git status?

On branch master
Changes to be committed:
  (use "git reset HEAD <file>..." to unstage)
        modified:   index.html
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)
        modified:   index.html

As we said before, we have everything ready for our next commit, but with the changes we realized to our file, Git (who is a smart-y pants) knows the actual file has been modified again. At this point, there’s two options, we are aware of this and we add the next modifications for the commit with a simple git add index.html or, just do the commit like we are going to do now which is going to show us why using a version control software helps a lot, let’s commit our file to the repository with git commit -m "Adding a striking message".

[master f7c5eba] Adding a striking message
 1 file changed, 1 insertion(+)

And once again, let’s see what git status has to say

On branch master
Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)
        modified:   index.html
no changes added to commit (use "git add" and/or "git commit -a")

We’re in trouble now… we just send our commit but without the latest changes, don’t worry, thanks to Git we can solve this (at least for now…). If we didn’t committed any more changes but the last one, we can revert this, first, with git add index.html and after just a simple git commit --amend, the text editor (hopefully is vim…) we selected in the start of this course will open the next text.

Adding a striking message

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Tue Nov 7 20:02:01 2017 +0100
#
# On branch master
# Changes to be committed:
#       modified:   index.html

The first part is the message we added to the commit, in case you added a wrong commit message feel free to change it now and finally, save the file and…

[master e02c63c] Adding a striking message
 Date: Tue Nov 7 20:02:01 2017 +0100
 1 file changed, 1 insertion(+)

If you are into details, you can see the ID for the commit changed from f7c5eba to e02c63c, because even when we revert a commit, Git knows there was a commit realized just before this one and it gives another ID for the “same file” commit.

This is it, as the people usually say, remember, you can check Our GitHub Repo where you can find the repository for this course with all the steps and lessons we do in here :)

And never… ever… stop programming!