$ git config core.logallrefupdates
true
$ cat .git/logs/refs/heads/master
$ git reflog show master|head -2
59a7f56 master;{0}: reset: moving to 59a7f56
2cfc8f7 master;{1}: reset: moving to HEAD^
$ git reset --hard master;{2}
HEAD 现在位于 a1720b0 does master follow this new commit?
$ git rev-parse HEAD
a1720b04420a95d8f46d925569ab5d5d3ee5fd4a
$ git reflog show master|head -3
a1720b0 master;{0}: reset: moving to master;{2}
59a7f56 master;{1}: reset: moving to 59a7f56
2cfc8f7 master;{2}: reset: moving to HEAD^
