git checkout, git reset, and git revert are all commands used to change the state of your Git repository, but they do so in different ways:

1. git checkout: This command is used to switch between different branches or different commits in your repository. When you use git checkout with a commit hash, you’re moving the HEAD pointer to that commit, effectively making it the current commit. This does not alter the commit history.
2. git reset: This command is used to move the HEAD pointer to a specific commit, similar to git checkout. However, git reset can also alter the commit history depending on how it’s used. There are three modes: --soft, --mixed, and --hard.
   • git reset --soft <commit>: Moves the HEAD pointer but does not change the staging area or the working directory.
   • git reset --mixed <commit> (default): Moves the HEAD pointer and changes the staging area to match the HEAD, but does not change the working directory.
   • git reset --hard <commit>: Moves the HEAD pointer and changes both the staging area and the working directory to match the HEAD.
3. git revert: This command is used to create a new commit that undoes the changes made in a specific commit. This does not move the HEAD pointer or alter the commit history (except for adding the new commit). This is a safe command to use if you want to undo changes but keep the history intact.

In summary, git checkout is used for navigating between commits, git reset is used for discarding changes and moving the HEAD pointer, and git revert is used for undoing changes in a safe manner.