How to fsck root file system without recovery CDs.

I met corruption of root file system with debian wheezy/sid.
Unfortunately,I didn't have any recovery CDs. Then I searched around a method of doing fsck root file system and I found a easy method. So I memorize here,

Step 1. Add 'forcefsck' to the boot entry in GRUB after system reboots.

linux   /boot/vmlinuz-2.6.37-2-686 root=UUID=XXXXX-XXX-XXXX-XXX-XXXXX ro  quiet forcefsck

Step 2. Type Ctrl+x and boot.

For a while , fsck of the root file system begins.