Introduction to Git Exercises
These exercises aim to give you some practice with using the Git version control system. Each
exercise comes in two parts: a main task that most, if not all, course attendees should be able to
complete in the allocated time, as well as a stretch task for those who complete the main task
quickly.
Exercise 1
Main Task
1. Create a new directory and change into it.
2. Use the init command to create a Git repository in that directory.
3. Observe that there is now a .git directory.
4. Create a README file.
5. Look at the output of the status command; the README you created should appear as an
untracked file.
6. Use the add command to add the new file to the staging area. Again, look at the output of
the status command.
7. Now use the commit command to commit the contents of the staging area.
8. Create a src directory and add a couple of files to it.
9. Use the add command, but name the directory, not the individual files. Use the status
command. See how both files have been staged. Commit them.
10. Make a change to one of the files. Use the diff command to view the details of the change.
11. Next, add the changed file, and notice how it moves to the staging area in the status
output. Also observe that the diff command you did before using add now gives no output.
Why not? What do you have to do to see a diff of the things in the staging area? (Hint:
review the slides if you can’t remember.)
12. Now – without committing – make another change to the same file you changed in step 10.
Look at the status output, and the diff output. Notice how you can have both staged and
unstaged changes, even when you’re talking about a single file. Observe the difference when
you use the add command to stage the latest round of changes. Finally, commit them. You
should now have started to get a feel for the staging area.
13. Use the log command in order to see all of the commits you made so far.
14. Use the show command to look at an individual commit. How many characters of the
commit identifier can you get away with typing at a minimum?
15. Make a couple more commits, at least one of which should add an extra file.
Stretch Task
1. Use the Git rm command to remove a file. Look at the status afterwards. Now commit the
deletion.
2. Delete another file, but this time do not use Git to do it; e.g. if you are on Linux, just use the
normal (non-Git) rm command; on Windows use del.
3. Look at the status. Compare it to the status output you had after using the Git built-in rm
command. Is anything different? After this, commit the deletion.
4. Use the Git mv command to move or rename a file; for example, rename README to
README.txt. Look at the status. Commit the change.
5. Now do another rename, but this time using the operating system’s command to do so. How
does the status look? Will you get the right outcome if you were to commit at this point?
(Answer: almost certainly not, so don’t. ) Work out how to get the status to show that it
will not lose the file, and then commit. Did Git at any point work out that you had done a
rename?
6. Use git help log to find out how to get Git to display just the most recent 3 commits. Try
it.
7. If you don’t remember, look back in the slides to see what the --stat option did on the
diff command. Find out if this also works with the show command. How about the log
command?
8. Imagine you want to see a diff that summarizes all that happened between two commit
identifiers. Use the diff command, specifying two commit identifiers joined by two dots
(that is, something like abc123..def456). Check the output is what you expect.
Exercise 2
Main Task
1. Run the status command. Notice how it tells you what branch you are in.
2. Use the branch command to create a new branch.
3. Use the checkout command to switch to it.
4. Make a couple of commits in the branch – perhaps adding a new file and/or editing existing
ones.
5. Use the log command to see the latest commits. The two you just made should be at the
top of the list.
6. Use the checkout command to switch back to the master branch. Run log again. Notice
your commits don’t show up now. Check the files also – they should have their original
contents.
7. Use the checkout command to switch back to your branch. Use gitk to take a look at the
commit graph; notice it’s linear.
8. Now checkout the master branch again. Use the merge command to merge your branch in
to it. Look for information about it having been a fast-forward merge. Look at git log, and
see that there is no merge commit. Take a look in gitk and see how the DAG is linear.
9. Switch back to your branch. Make a couple more commits.
10. Switch back to master. Make a commit there, which should edit a different file from the
ones you touched in your branch – to be sure there is no conflict.
11. Now merge your branch again. (Aside: you don’t need to do anything to inform Git that you
only want to merge things added since your previous merge. Due to the way Git works, that
kind of issue simply does not come up, unlike in early versions of Subversion.)
12. Look at git log. Notice that there is a merge commit. Also look in gitk. Notice the DAG
now shows how things forked, and then were joined up again by a merge commit.
Stretch Task
1. Once again, checkout your branch. Make a couple of commits.
2. Return to your master branch. Make a commit there that changes the exact same line, or
lines, as commits in your branch did.
3. Now try to merge your branch. You should get a conflict.
4. Open the file(s) that is in conflict. Search for the conflict marker. Edit the file to remove the
conflict markers and resolve the conflict.
5. Now try to commit. Notice that Git will not allow you to do this when you still have
potentially unresolved conflicts. Look at the output of status too.
6. Use the add command to add the files that you have resolved conflicts in to the staging
area. Then use commit to commit the merge commit.
7. Take a look at git log and gitk, and make sure things are as you expected.
8. If time a