2024-06-01

Obscure Useful Commands

Obscure Commands That Are Useful

Intro: This post I have tried talking about some obscure commands, that can save your back when you need them. I have tried keeping every section short and concise. No BS.

Table of Contents

• Git
  • Edit commit history to prevent private email from showing up
  • Delete Commit History

Git

Edit commit history to prevent private email from showing up

Desc: Suppose you have accidentally revealed your private@mail.com by commiting and pusing it to github. How do you safely change that email to public@mail.com so that it overwrites your commit history? Here is what you need to do.

1. Backup the repo your with all the latest changes. In case you make some mistake. Also make sure to commit any changes that you might have made to the repo but have not pushed yet.

   cp -r /path/to/repo /path/to/repo.bak
   

2. Do a fresh commit of the repo and cd inside it:

   git clone git@github.com:user/repo.git
   cd repo
   

3. Install git-filter-repo. We are going to use this tool to overwrite our commit history.

   Debian/Ubuntu/Mint:

   apt install git-filter-repo
   

   Arch Linux:

   pacman -S git-filter-repo
   

   Void Linux:

   xbps-install git-filter-repo
   

   Use sudo if needed.

   Others follow the link.

4. Overwrite the repo’s commit history:

   git filter-repo --commit-callback '
   if commit.author_email == b"private@mail.com":
   commit.author_email = b"public@mail.com"
   if commit.committer_email == b"private@mail.com":
   commit.committer_email = b"public@mail.com"
   '
   

   Change private@mail.com with your unwanted exposed mail address and public@mail.com with your new mail address.

5. Now force push all the changes.

   git push --force --all
   

   Thats it! You can see if your private email is still showing in the commit history by running git log | grep private@mail.com.

Delete Commit History

Desc: Commits can be undone, and you can erase the history just like that. ft. git reset.

1. Use git log to see your commit history.

2. After identifying which commit to erase, run:

   git reset --hard <commit-hash>
   

   Example:

   git reset --hard 0ceef5d2d76a88d07e2e4f8e050cc082ee31b4c4
   

   Here, 0ceef5d2d76a88d07e2e4f8e050cc082ee31b4c4 represents unique the hash for the commit.

   This command will delete the entire commit history up until the commit: 0ceef5d2d76a88d07e2e4f8e050cc082ee31b4c4.

   You can also do the same using HEAD~n. Example:

   git reset --hard HEAD~5
   

   This will erase the last 5 commits from your history.

3. Verify that your desired commit is gone forever from the face of the earth.

   git log
   

4. Now, force push your changes.

   git push --force --all