hammer

[lelf@dragon ~]$ echo 11111111 > myfile
[lelf@dragon ~]$ sync
[lelf@dragon ~]$ echo 22222222 >> myfile
[lelf@dragon ~]$ sync

[lelf@dragon ~]$ hammer history myfile
myfile	00000001073a3ee6 clean {
    00000001073abc60 08-Dec-2013 23:05:34
    00000001073abd20 08-Dec-2013 23:05:47
}

[lelf@dragon ~]$ undo -t 00000001073abc60 myfile

>>> myfile 0000 0x00000001073abc60 08-Dec-2013 23:05:34

11111111

[lelf@dragon ~]$ rm myfile

[lelf@dragon ~]$ ls myfile
ls: myfile: No such file or directory

[lelf@dragon ~]$ undo -a myfile
myfile: ITERATE ENTIRE HISTORY

>>> myfile 0001 0x00000001073abc20 08-Dec-2013 23:05:15

11111111
22222222

>>> myfile 0002 0x00000001073abc60 08-Dec-2013 23:05:34

11111111