Scenario

A file named secrets.env containing sensitive credentials exists in the repository's commit history. You need to purge this file from the entire history.

Task

Navigate to /home/interview/repo and rewrite the commit history to permanently remove secrets.env from all commits.

Example

# Before (Sensitive data in history)
$ git log --all --oneline -- secrets.env
a1b2c3d Add secrets file

# After (Clean history)
$ git log --all --oneline -- secrets.env
(no output)

Step 1: Navigate and audit history
Move to the repository and confirm the file exists in the history.

cd /home/interview/repo
git log --all --oneline -- secrets.env

Step 2: Rewrite history
Run the filter command to remove the file from every commit in all branches.
(Note: We use --tree-filter to execute the removal on every commit checkout).

FILTER_BRANCH_SQUELCH_WARNING=1 git filter-branch --force --tree-filter 'rm -f secrets.env' --prune-empty -- --all

Step 3: Cleanup backup artifacts
Delete the backup refs created by the filter command to ensure the data is truly gone.

# Delete the backup refs created by filter-branch so the old history is no longer linked.
rm -rf .git/refs/original/