Hi,
It's quite simple if you do it on a no-root partition. For example, you want to check /usr partition which is represented in /dev by /dev/hda2 and which is ext3 formatted, simply do the following:
Code:
umount /usr
fsck.ext3 -a /dev/hda3
mount /usr
Note that during these steps you can't use anymore software and libraries located in /usr. That's why it's a bit more complex when you want to do that for root partition... A solution is to create a ramdisk FS which will contain /bin /sbin and libraries stuff, you mount it in RAM and then you can check your root partition
Oliv'