View Git "undo" history

Sometimes, git log doesn't cut it, especially for commands that don't show up in your commit history. Fortunately, there's a way to view your "undo" history. git reflog is basically your safety net after running "scary" commands like git rebase. It allows you to see not only the commits you made, but each of the actions that led you there.
To view you "undo" history, you can use git reflog, which displays the git reference log:
After you've found the commit you want, you can use git reset to go back to it.

git reflog
# b6a4f9d6ff9 (HEAD -> patch-1, origin/patch-1) HEAD@{0}: Update docs
# 3050fc0de HEAD@{1}: rebase -i (finish): returning to refs/heads/patch-1
# 3050fc0de HEAD@{2}: rebase -i (pick): Fix network bug
# 93df3f495 (origin/patch-2) HEAD@{3}: rebase -i (start): checkout origin/master
# 69beaeabb HEAD@{4}: rebase -i (finish): returning to refs/heads/patch-1

After you've found the commit you want, you can use git reset to go back to it.

From 30-seconds-of-code: view-undo-history