Reflog for finding lost commits in Git - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to show the reflog entries.

Git

git [1]

Drag options to blanks, or click blank then click option'

Areflog

Bbranch

Clog

Dstatus

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'git log' instead of 'git reflog' to find lost commits.

The git reflog command shows the history of HEAD changes, helping find lost commits.

2fill in blank

medium

Complete the command to reset the current branch to a lost commit found in reflog.

Git

git reset --hard [1]

Drag options to blanks, or click blank then click option'

AHEAD~2

Borigin/main

CHEAD@{3}

Dmaster

Attempts:

3 left

💡 Hint

Common Mistakes

Using branch names like 'master' or 'origin/main' instead of reflog references.

The syntax HEAD@{3} refers to the third previous position of HEAD in reflog.

3fill in blank

hard

Fix the error in the command to show reflog with commit hashes and messages.

Git

git reflog [1] --oneline

Drag options to blanks, or click blank then click option'

A--graph

B--pretty=oneline

C--format=oneline

D--decorate

Attempts:

3 left

💡 Hint

Common Mistakes

Using --format without --pretty or using unrelated options.

The --pretty option customizes the output format, including showing commit hashes and messages.

4fill in blank

hard

Fill both blanks to create a command that shows reflog entries with timestamps and author info.

Git

git reflog [1] [2]

Drag options to blanks, or click blank then click option'

A--pretty=format:'%h %ad %an %s'

B--oneline

C--date=iso

D--graph

Attempts:

3 left

💡 Hint

Common Mistakes

Using --oneline which lacks detailed info.

Mixing up date formatting options.

The --pretty=format:'%h %ad %an %s' shows hash, date, author, and message. The --date=iso formats the date nicely.

5fill in blank

hard

Fill all three blanks to create a command that recovers a lost commit by creating a new branch at that commit.

Git

git branch [1] [2] && git checkout [3]

Drag options to blanks, or click blank then click option'

Arecovered-branch

BHEAD@{5}

Dmaster

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'master' instead of the new branch name for checkout.

Not using reflog syntax for the commit.

This command creates a new branch named recovered-branch at the lost commit HEAD@{5} and then switches to it.

Practice

1. What is the primary purpose of git reflog?

easy

A. To list all remote branches

B. To permanently delete commits from the repository

C. To record where HEAD and branches have pointed recently

D. To merge two branches automatically

Solution

1. Step 1: Understand what reflog tracks

   Reflog records the history of where HEAD and branch references have pointed, including commits that might be lost after resets or rebases.

2. Step 2: Compare options with reflog purpose

   Only To record where HEAD and branches have pointed recently correctly describes reflog's role. Options B, C, and D describe unrelated git functions.

3. Final Answer:

   To record where HEAD and branches have pointed recently -> Option C

4. Quick Check:

   Reflog tracks HEAD history = A [OK]

Hint: Reflog shows recent HEAD moves, like a safety net [OK]

Common Mistakes:

• Confusing reflog with git log
• Thinking reflog deletes commits
• Assuming reflog lists remote branches

2. Which command correctly shows the reflog entries?

easy

A. git reflog

B. git reflog list

C. git reflog -a

D. git reflog --show

Solution

1. Step 1: Recall the basic reflog command

   The simplest and correct command to show reflog entries is git reflog.

2. Step 2: Evaluate other options

   git reflog --show is invalid; git reflog list and git reflog -a are invalid commands.

3. Final Answer:

   git reflog -> Option A

4. Quick Check:

   Basic reflog command = git reflog [OK]

Hint: Use just 'git reflog' to see recent HEAD moves [OK]

Common Mistakes:

• Adding unnecessary subcommands like 'list'
• Using invalid flags like '-a'
• Confusing reflog with git log

3. After running git reset --hard HEAD~1, you realize you lost a commit. Which command helps you find the lost commit's hash?

medium

A. git reflog

B. git status

C. git branch

D. git log --oneline

Solution

1. Step 1: Understand what happens after reset

   git reset --hard HEAD~1 moves HEAD back one commit, making the latest commit unreachable but still in reflog.

2. Step 2: Identify command to find lost commit

   git reflog shows recent HEAD positions including the lost commit's hash. Other commands won't show unreachable commits.

3. Final Answer:

   git reflog -> Option A

4. Quick Check:

   Reflog shows lost commits after reset = C [OK]

Hint: Use reflog to find commits lost by reset [OK]

Common Mistakes:

• Using git status which shows working tree only
• Using git branch which lists branches, not commits
• Using git log which hides unreachable commits

4. You ran git reset --hard HEAD~2 but want to restore the latest commit. Which command correctly resets to the lost commit using reflog?

medium

A. git reset --hard HEAD@{2}

B. git reset --hard origin/main

C. git reset --hard HEAD~1

D. git reset --hard HEAD@{1}

Solution

1. Step 1: Understand reflog indexing

   After resetting HEAD back two commits, reflog entries show HEAD@{0} as current, HEAD@{1} as previous position (the lost commit), and HEAD@{2} as older.

2. Step 2: Choose correct reflog entry to restore

   To restore the latest lost commit, reset to HEAD@{1} which points to it. HEAD@{2} is older, HEAD~1 is relative to current HEAD, and origin/main may differ.

3. Final Answer:

   git reset --hard HEAD@{1} -> Option D

4. Quick Check:

   Use HEAD@{1} to restore last HEAD position [OK]

Hint: Reset to HEAD@{1} to undo last reset [OK]

Common Mistakes:

• Using HEAD@{2} which is older than needed
• Using HEAD~1 which is relative to current HEAD
• Resetting to origin/main which may differ

5. You accidentally deleted a branch with important commits. How can you recover the lost commits using reflog?

hard

A. Run git branch -d to restore the branch

B. Find the commit hash in git reflog and create a new branch at that hash

C. Use git reset --hard origin/branch-name to recover commits

D. Re-clone the repository to get the branch back

Solution

1. Step 1: Locate lost commits in reflog

   Deleted branch commits remain in reflog as recent HEAD positions or branch references before deletion.

2. Step 2: Create a new branch at the lost commit hash

   After finding the commit hash in reflog, use git branch new-branch-name <commit-hash> to restore the branch with lost commits.

3. Final Answer:

   Find the commit hash in git reflog and create a new branch at that hash -> Option B

4. Quick Check:

   Reflog + new branch recovers deleted commits [OK]

Hint: Use reflog hash to recreate deleted branch [OK]

Common Mistakes:

• Trying to delete branch again to restore it
• Resetting to origin which may not have deleted commits
• Re-cloning loses local lost commits