Find out your quota status.  You can determine whether you are under or
over your disk quota, and exactly how much disk space your files are using.

WARNING:  You will permanently lose the contents of any file you edit if,
 * you've been warned three times that your disk usage exceeds the quota, and
 * you attempt to save the file without having reduced your disk space to
   less than 500 kilobtyes, i.e., 0.5 megabytes.
