Disk Quotas in Linux

You have to setup your file system with disk quota enabled. Then you can use the following commands to manipulate your disk quotas

root@xyz:~# quotacheck
root@xyz:~# quotaon
root@xyz:~# edquota
root@xyz:~# quota
root@xyz:~# repquota


You can futher read the following articles

1. Managing Disk Usage with Quotas
   
2. Implementing quotas to restrict disk space usage
   
3. Manage user accounts in a multi-user Linux environment with disk quotas
   
4. Disk quotas