Ubuntu 6.06:
Implementing quota on /home

1] sudo aptitude install quota
2] edit /etc/fstab placing the usrquota,grpquota on the filesystem you want quota implemented.
3] sudo touch /home/quota.user /home/quota.group

4] sudo chmod 600 /home/quota.*

5] sudo mount -o remount /home

6] sudo quotacheck -avugm

7] sudo quotaon -avug

8]Edit quota for a user

sudo edquota <username>

e.g sudo edquota user1

9] report the quota usage

sudo repquota <device name>

e.g. repquota /dev/sda10

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Ubuntu 6.10
Implementing quota on the /

1] sudo aptitude install quotatool
2] edit /etc/fstab placing the usrquota,grpquota on the filesystem you want quota implemented.
3] sudo touch /quota.user /quota.group

4] sudo chmod 600 /quota.*

5] sudo mount -o remount /

6] sudo quotacheck -avugm

7] sudo quotaon -avug

Reference:

http://www.debianadmin.com/implement-and-manage-disk-quotas-in-linux.html