Module 2

Question 1

What does HEAD represent in Git?

Answer 1

The currently checked-out snapshot of your project

Question 2

What is the purpose of the git checkout command?

Answer 2

It reverts changes to modified files before they are staged.

It will revert to state from HEAD.

Question 2

What is the gitignore file

Question 3

What is the purpose of the git checkout -p command?

Answer 3

It allows reverting specific changes only. Git will go through change by change and ask if I want to revert.

Question 4

What is the purpose of the git reset command?

Answer 4

It reverts changes to modified files after they’ve been staged.

It will revert to state from HEAD.

output.txt was incorrectly stagged by the git add * command

Question 5

How to use the git reset command?

Answer 5

git reset HEAD <file name>

Question 6

How to use the git checkout command?

Answer 6

git checkout <file name>

Question 7

What does the git commit --amend do?

Answer 7

Overwrite the previous commit.

Question 8

When git commit --amend should not be used? Why so?

Answer 8

Avoid using it when commit has been pushed to a public/shared repository. It is acceptable only for local repositories.

The reason is that git commit --ammend will overwrite previous commit and can lead to confusing situations when collaborating with others on the same code.

Question 9

What does the git revert do?

Answer 9

It creates a new commit with inverse changes.

Git does not delete the problematic commit as this would mean we would lose track of project history.

Question 10

How to use git revert?

Answer 10

It is good to add the reason for the rollback on the commit message.

Question 11

How to revert to a commit other than the previous one?

Answer 11

Use the commit ID as argument instead of HEAD
~~~
git revert abb063210c1f011b0d6470a4c5f1d8f672edd3ef
~~~

Question 12

How does Git ensure the commit ID is unique to each commit?

Answer 12

It uses the SHA1 algorithm to create a hash that takes into consideration the commit message, date, author, and the snapshot taken of the working tree.

Therefore, the chances that two different commits have the same hash is virtually impossible and if it does happen, it is an indicator that something went wrong (e.g. tampering with the repository)

Question 13

What does the git checkout -b new branch command do?

Answer 13

Creates a new branch and switches to it.

Question 14

How does git checkout switch branches?

Answer 14

By updating the working tree to match the selected branch.

Question 15

What happens when we merge two branches?

Answer 15

Both branches are pointed at the same commit.

Question 16

What is the purpose of organizing repositories into branches?

Answer 16

To enable changes to be worked on without disrupting the most current working state.

Question 17

How do I know in which branch am I currently?

Answer 17

Use git branch and look for the branch preceded by an asterisk *

Currently in the master branch in this example

Question 18

Is is possible to delete a branch?

Answer 18

git branch -d <branch_name>

In case there are changes not commited, Git will ask us to confirm if we still want to delete it.

To overwrite this step, use git branch -D <branch_name> instead.

Question 19

What’s the advantage of Git throwing a merge conflict error in cases of overlap?

Answer 19

It prevents loss of work if two lines overlap.

Question 20

When we merge two branches, one of two algorithms is used. If the branches have diverged, which algorithm is used?

Answer 20

Three-way merge

Question 21

What command would we use to throw away a merge, and start over?

Answer 21

git merge --abort

Question 22

What is the purpose of a Git repository, and how does it facilitate version control?

Answer 22

A Git repository is a version control system that tracks changes to source code, allowing multiple developers to collaborate, review changes, and maintain a complete history of project revisions.

Question 23

In a Git repository, what command would you use to create a new branch based on the current branch, and what command would you use to switch to that newly created branch?

Answer 23

To create a new branch, use git branch new-branch-name, and to switch to it, use git checkout new-branch-name

Question 24

What is the primary purpose of merging a branch back into the main branch in a Git repository?

Answer 24

To combine the changes from the branch into the main codebase