Sharing your work
Overview
Teaching: 30 min
Exercises: 0 minQuestions
What does
pushandpullmean?Objectives
create a repository on GitHub
link a local repository with a repository on GitHub
push changes from the local repository to GitHub
pull changes back from GitHub to the local repository
Create a repository
When we have logged in to GitHub, we can create a new repository by clicking the + icon in the upper-right corner of any page then selecting New repository. Let’s do this now.
- Create a new repository
- Give it the name
hello-world
GitHub will ask if you want to add a README.md, license or a .gitignore file. Do not do any of that for now.
Choosing a license
Choosing a license is an important part of openly sharing your creative work online. For help in wading through the many types of open source licenses, please visit https://choosealicense.com/.
Connecting your local repository to a remote repository
We now need to link the local repository that we created in the previous lesson with the remote repository that we have just created on GitHub.
$ git remote add origin <web_address_of_your_repo.git>
Why
origin?
originin thegit remote addline is just a short name or alias we’re giving to that big long repository URL. It could be almost any string we want, but by convention in git, it is usually calledorigin, representing where the repo originated.
We can check that it is set up correctly with the command:
$ git remote -v
origin https://github.com/<your_github_username>/hello-world (fetch)
origin https://github.com/<your_github_username>/hello-world (push)
“Pushing” changes
To add the changes we previously made to our local repository to the remote repository that we have just created on
GitHub we need to run the git push command.
$ git push -u origin master
Counting objects: 3, done.
Writing objects: 100% (3/3), 226 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To https://github.com/<your_github_username/hello-world
* [new branch] master -> master
Branch master set up to track remote branch master from origin.
PS C:\github\hello-world> git status
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working tree clean
The nickname of our remote is origin and the default local branch name is master. The -u flag tells git to remember
the parameters, so that next time we can simply run git push and Git will know what to do. Go ahead and push it!
You may be prompted to enter your GitHub username and password to complete the command.
When we do a git push, we will see Git ‘pushing’ changes upstream to GitHub. Because our file is very small, this
won’t take long but if we had made a lot of changes or were adding a very large repository, we might have to wait a
little longer. We can check where we’re at with git status.
$ git status
On branch master
Your branch is up-to-date with 'origin/master'.
nothing to commit, working tree clean
This output lets us know where we are working (the master branch). We can also see that we have no changes to commit and everything is in order.
We can use the git diff command to see changes we have made before making a commit. Open index.md with any text
editor and enter a new line.
$ git diff
diff --git a/index.md b/index.md
index aed0629..989787e 100644
--- a/index.md
+++ b/index.md
@@ -1 +1,2 @@
-# Hello, world!
\ No newline at end of file
+# Hello, world!
+A new line
We can see the changes we have made.
- The first line tells us that Git is producing output similar to the Unix diff command comparing the old and new versions of the file.
- The second line tells exactly which versions of the file Git is comparing;
aed0629and989787eare unique computer-generated identifiers for those versions. - The third and fourth lines once again show the name of the file being changed.
- The remaining lines are the most interesting; they show us the actual differences and the lines on which they occur. In particular, the + markers in the first column show where we have added lines.
We can now commit these changes again:
$ git add index.md
$ git commit -m 'Add another line'
If we are very forgetful and have already forgotten what we changes we have made, git log allows us to look at what
we have been doing with our git repository (in reverse chronological order, with the very latest changes first).
$ git log
commit 8e2eb9920eaa0bf18a4adfa12474ad58b765fd06
Author: Your Name <your_email>
Date: Mon Jun 5 12:41:45 2017 +0100
Add another line
commit e9e8fd3f12b64fc3cbe8533e321ef2cdb1f4ed39
Author: Your Name <your_email>
Date: Fri Jun 2 18:15:43 2017 +0100
Add index.md
This shows us the two commits we have made and shows the messages we wrote. It is important to try to use meaningful commit messages when we make changes. This is especially important when we are working with other people who might not be able to guess as easily what our short cryptic messages might mean. Note that it is best practice to always write commit messages in the imperative (e.g. ‘Add index.md’, rather than ‘Adding index.md’).
We might get a lit bit lonely working away on our own and want to work with other people. Before we get to that, it is worth learning a couple more git commands.
Pushing changes
If we have another look at our repository on GitHub, we can see that only our first change is there. This is because we haven’t yet pushed our local changes to the remote repository. This might seem like a mistake in design but it is often useful to make a lot of commits for small changes so you are able to make careful revisions later and you don’t necessarily want to push all these changes one by one.
Let’s push our changes now, using the git push command.
Pushing and Pulling
$ git push
Counting objects: 3, done.
Writing objects: 100% (3/3), 272 bytes | 0 bytes/s, done.
Total 3 (delta 0), reused 0 (delta 0)
To https://github.com/<your_github_username>/hello-world
e9e8fd3..8e2eb99 master -> master
Pulling changes
When working with others, or when we’re making our own changes from different machines, we need a way of pulling those remote changes back into our local copy. For now, we can see how this works by making a change on the GitHub website and then ‘pulling’ that change back to our computer.
Let’s go to our repository in GitHub and make a change. Underneath where our index.md file is listed you will see a button to ‘Add a README’. Do this now, entering whatever you like, scrolling to the bottom and clicking ‘Commit new file’ (The default commit message will be ‘Create README.md’, which is fine for our purposes).
The README file
It is good practice to add a README file to each project to give a brief overview of what the project is about. If you put your README file in your repository’s root directory, GitHub will recognize and automatically surface your README to repository visitors
Our local repository is now out of sync with our remote repository, so let’s fix that by pulling the remote changes into
our local repository using the git pull command.
$ git pull
remote: Counting objects: 3, done.
remote: Compressing objects: 100% (2/2), done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Unpacking objects: 100% (3/3), done.
From https://github.com/<your_github_username>/hello-world
8e2eb99..0f5a7b0 master -> origin/master
Updating 8e2eb99..0f5a7b0
Fast-forward
README.md | 1 +
1 file changed, 1 insertion(+)
create mode 100644 README.md
The above output shows that we have fast-forwarded our local repository to include the file README.md. We could confirm
this by entering the ls command.
When we begin collaborating on more complex projects, we may have to consider more aspects of git functionality, but this should be a good start. In the next section, we can look more closely at collaborating and using GitHub pages to create a website for our project.
Key Points
remote repositories on GitHub help you collaborate
pushis a Git verb for sending changes from the local repository to a remote repository
pullis a Git verb for bringing changes from a remote repository to the local repository