[git] What's the difference between Git Revert, Checkout and Reset?

I am trying to learn how to restore or rollback files and projects to a prior state, and don't understand the difference between git revert, checkout, and reset. Why are there 3 different commands for seemingly the same purpose, and when should someone choose one over the other?

If you broke the tree but didn't commit the code, you can use git reset, and if you just want to restore one file, you can use git checkout.

If you broke the tree and committed the code, you can use git revert HEAD.

http://book.git-scm.com/4_undoing_in_git_-_reset,_checkout_and_revert.html

• git checkout modifies your working tree,
• git reset modifies which reference the branch you're on points to,
• git revert adds a commit undoing changes.

Let's say you had commits:

C
B
A

git revert B, will create a commit that undoes changes in B.

git revert A, will create a commit that undoes changes in A, but will not touch changes in B

Note that if changes in B are dependent on changes in A, the revert of A is not possible.

git reset --soft A, will change the commit history and repository; staging and working directory will still be at state of C.

git reset --mixed A, will change the commit history, repository, and staging; working directory will still be at state of C.

git reset --hard A, will change the commit history, repository, staging and working directory; you will go back to the state of A completely.

Reset - On the commit-level, resetting is a way to move the tip of a branch to a different commit. This can be used to remove commits from the current branch.

Revert - Reverting undoes a commit by creating a new commit. This is a safe way to undo changes, as it has no chance of re-writing the commit history. Contrast this with git reset, which does alter the existing commit history. For this reason, git revert should be used to undo changes on a public branch, and git reset should be reserved for undoing changes on a private branch.

You can have a look on this link- Reset, Checkout and Revert

• git revert is used to undo a previous commit. In git, you can't alter or erase an earlier commit. (Actually you can, but it can cause problems.) So instead of editing the earlier commit, revert introduces a new commit that reverses an earlier one.
• git reset is used to undo changes in your working directory that haven't been comitted yet.
• git checkout is used to copy a file from some other commit to your current working tree. It doesn't automatically commit the file.