unclean shutdown in ubuntu

example unclean shutdown for /dev/sda2
- run

root ~ # fsck /dev/sda2
fsck 1.38 (30-Jun-2005)
e2fsck 1.38 (30-Jun-2005)
/dev/sda2 have system errors, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
/lost+found not found. Create? y
.
.
.
.
.
/dev/sda2: ***** FILE SYSTEM WAS MODIFIED *****
/dev/sda2: ***** REBOOT LINUX *****

root ~ # init 6

-----------blue graphic error screen appears\
devian login: username
password:

ria@devian:~$ init 0

-----------turn on your computer

Hurray! its working!