git reset --soft/--mixed/--hard

git reset explained.md

UPDATE

Every time I accidentally git commit --amend instead of a normal git commit I have to google git reset --soft HEAD@{1} to save the day.

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Imagine you have a file called foo.txt and your Git history looked like this:

A -> B -> C (HEAD)

Let's see each commit we made:

A == foo
B == FOO
C == Foo

The following examples explain the different reset flags:

git reset --soft B  == move HEAD to B but keep C's changes staged (i.e. added to the index)

git reset --mixed B == move HEAD to B but keep C's changes unstaged (--mixed is the DEFAULT)

git reset --hard B  == move HEAD to B but completely delete C (you've lost those changes forever)

NOTE: If you accidentally git commit --amend the HEAD, then you can undo that using git reset --soft HEAD@{1}. The --soft means the changes you made are kept staged (ready for an actual git commit) while the HEAD@{1} means set HEAD to what it was before the accidental --amend. This means HEAD@{1} is NOT the same thing as HEAD~1, which gives you the commit that is the parent node of the commit that HEAD is currently pointing to. The reference HEAD@{1} is actually able to get back what we want because what it references is actually sourced from git reflog, which if you run git reflog you'll see the output shows an index for each recorded change.

If you want to clean up a PRs commits, then run:

git reset origin/main 

Then your changes will still exist, but will just be unstaged (as --mixed is the default behaviour). You can now git add --patch cleanly.