i suspect that i have hdd error or maybe a back sector in my linux partition.
when i wanted to check my hdd and typed e2fsck /dev/hda10 theres a warning that if i check file system on mounted drive it will cause a severe filesystem damage?

what is the stright forward easy to follow method to check my linux partition and then view detail result about my linux partition condition.?

thanx in advance

If the partition isn't your root partition, then in a shell, su to root, and enter
umount /dev/hda10
Or your could type as root: mount /dev/hda10 -o ro,remount
This would remount the partition as readonly.

I'm not familiar with Red Hat 9, but they may have a graphical program wich would allow you to umount a partition also.
Also, look at the man page for fsck, If the partition is ext3, you will want to use fsck -t ext3 /dev/hda10 or maybe fsck.ext3 /dev/hda10.

If you still can't get the partition unmounted, you may want to boot with your rescue disk, or temporarily comment out the /dev/hda10 line in your /etc/fstab file.
If /dev/hda10 is your root partition, you have to boot with a rescue disk.

i've boot in rescue disk of my redhat 9 cd disk 1
then all runs fine.
and the result is that something look like this
pass1: XXXXXXXXXXX
pass2: XXXXXXXXXx
pass3: XXXXXXXXXx
pass4: XXXXXXXXX
pass5: XXXXXXXX

i use this command
e2fsck -c /dev/hda10

how do i know whether it really check for bad sector since the output from that scan didnt show any detail about bad sector.

About e2fsck:
-c scans for badblocks, -f forces an check of the file system meta data (ie. inodes, directories) You might want to run check check aswell.

Amazingly, I've posted this trick several times in the past few days, so I'll sumarize it for now

telinit 1
mount -o remount,ro /
e2fsck -f /dev/hda..
mount -o remount,rw /
telinit 5 (or check 'runlevel' for your current/previous runlevel)