git commit -a -m "wrong commit, needs changes"    # commit only staged changes, miss untracked changes
git add forgotten_file edited_file ...            # stage the changes to fix previous commit
git commit --amend --no-edit                      # commit staged changes, without editing commit message
git commit --amend -m "revised commit message"    # edit commit message, and commits staged changes if any

git commit --amend --reset-author                 # revise commit author info (for when done as wrong user)

• revert creates new commit(s) to undo commit(s).
• reset discards a commit.

Following command discards the last commit completely.

git reset --hard HEAD~1