This log is updated when the HEAD gets updated.

This usually happens with:

• Switching branches
• Pulling in new changes
• Adding new commits
• Rewrites to history

This command will show you the history of your local repository.

If you performed a destructive command like reset and want to recover commits, you could find the hash of this commit with git-reflog.

git log --oneline
00617f7 add bacon file
baee97e add new feature
62f8afd did bug fix
ed937bb initial commit

git reset --hard 62f8afd
HEAD is now at 62f8afd did bug fix
 
ls
index.html

git reflog
62f8afd HEAD@{0}: reset: moving to 62f8afd
00617f7 HEAD@{1}: commit: add bacon file
baee97e HEAD@{2}: merge new feature: Fast-forward
62f8afd HEAD@{3}: checkout: moving from new-feature to master
baee97e HEAD@{4}: rebase finished: returning to refs/heads/new-feature
baee97e HEAD@{5}: rebase: add new feature
62f8afd HEAD@{6}: checkout: moving from master to 62f8afd8bc86ec01e3472df
62f8afd HEAD@{7}: merge bug-fix: Fast forward
ed937bb HEAD@{8}: checkout: moving from bug-fix to master
62f8afd HEAD@{9}: commit: did bug fix
ed937bb HEAD@{10}: checkout: moving from master to bug-fix 
ed937bb HEAD@{11}: checkout: moving from new-feature to master
ff70d17 HEAD@{12}: commit: add new feature
ed937bb HEAD@{13}: checkout: moving from master to new-feature
ed937bb HEAD@{14}: commit (initial): initial commit
 
git reset --hard 00617f7
HEAD is now at 00617f7 add bacon file
 
ls
bacon.html index.html new-feature.html

You could always use git reset –hard [commit hash] to revert accidentally changes.