Cheat sheet & self-check

Pick an answer to see if you got it, and why.

1. Q1. What does a Git commit store?

   1. AOnly the lines that changed
   2. BA snapshot of the whole project (as a tree), plus author, message and a link to its parent commit(s)
   3. CA copy of the remote
   4. DA diff against main
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   B. Git stores snapshots; diffs are computed when you ask for them. Unchanged files are shared between snapshots, so it stays small.

   From lesson 01 · How Git works

2. Q2. What is a branch in Git?

   1. AA copy of the whole repository
   2. BA movable label (a file containing a commit SHA) that advances when you commit
   3. CA folder
   4. DA server-side feature only
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   B. Branches are cheap pointers. Creating one writes one small file; that's why branching in Git is instant.

   From lesson 01 · How Git works

3. Q3. Between which areas does `git add` move changes?

   1. AWorking tree → staging area (index)
   2. BStaging area → remote
   3. CRemote → working tree
   4. DCommit → working tree
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   A. `git add` stages changes into the index; `git commit` turns the index into a new snapshot.

   From lesson 01 · How Git works

4. Q4. Why can't a commit be changed without its SHA changing?

   1. AGit forbids editing
   2. BThe SHA is a hash of the commit's content, including its parent's SHA, so any change produces a different commit
   3. CSHAs are random
   4. DThe server locks it
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   B. Content addressing makes history tamper-evident: changing anything in the past changes every SHA after it.

   From lesson 01 · How Git works

5. Q5. You changed a bug fix and some unrelated formatting in the same file. How do you make two clean commits?

   1. AYou can't, commit the whole file
   2. Bgit add -p to stage only the bug-fix hunks, commit, then stage and commit the rest
   3. CCreate two branches
   4. DUse git stash
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   B. Interactive staging lets each commit contain exactly one logical change, which makes review, revert and blame far more useful.

   From lesson 02 · The everyday workflow

6. Q6. What belongs in .gitignore for an infrastructure repository?

   1. ATerraform .tf files
   2. BLocal state, .terraform/ directories, plan files, .env files, credentials and editor junk
   3. CThe README
   4. DHelm charts
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   B. Ignore generated, local and secret files. Never rely on .gitignore alone for secrets though; scan for them too.

   From lesson 02 · The everyday workflow

7. Q7. When is git commit --amend safe?

   1. AAlways
   2. BOnly before the commit has been pushed/shared, because it replaces the commit with a new SHA
   3. COnly on main
   4. DNever
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   B. Amending rewrites the commit. Once others have it, rewriting forces them to reconcile diverged history.

   From lesson 02 · The everyday workflow

8. Q8. When does a merge become a fast-forward?

   1. AAlways
   2. BWhen the target branch has no new commits since the feature branch was created, so Git just moves the label forward
   3. CWhen there are conflicts
   4. DWhen using rebase
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   B. If main hasn't moved, no merge commit is needed: main simply points at the feature's latest commit.

   From lesson 03 · Branching and merging

9. Q9. What's the golden rule of rebasing?

   1. AAlways rebase main
   2. BDon't rebase commits that others already have (shared/pushed branches), because rebasing rewrites them with new SHAs
   3. CRebase only on Fridays
   4. DNever rebase
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   B. Rebasing your own local or personal branch is fine. Rewriting shared history forces everyone else to untangle it.

   From lesson 03 · Branching and merging

10. Q10. What do the conflict markers <<<<<<<, ======= and >>>>>>> separate?

    1. AThree versions of the file
    2. BYour side of the change, and the incoming side, which you must combine into the correct result
    3. CComments
    4. DDeleted lines
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    B. Git couldn't combine the edits automatically. You decide the final content, remove the markers, then add the file.

    From lesson 03 · Branching and merging