I want to give quota for each user on my linux box, so that each one will get only specified amount of disk space.
Ideally you will have /home as a separate partition. If you do, try this:
Find the filesystem for /home, for example:
mount | grep "/home"
/dev/sda3 on /home type ext3 (rw,noatime,errors=remount-ro)
mount -o remount,quota /home
Set the soft and hard quotas in there. This will only apply for the current boot, to make it survive a reboot edit /etc/fstab and add ",quota" to the end of the mount options for /dev/sda3 (in this example).
Google is your friend
Fredley tutorial is kinda out of date. This one is the one you need: Quota Mini Howto
Basically you need to enable quotas on
/etc/fstab and configure the quotas using the quota tools (
edquota, mainly). Is also cool to configure
quotacheck as a cron job.
Remember that quota is enabled per filesystem, so if you have 3 different partitions you have to enable and edit the quotas on each one of them. Just read the howto carefully and you will be set.