“One of the most important tasks of an administrator is to
maintain the users of the system. This includes not only making
sure that users can do certain things, it also means making sure
that the cannot do certain things. Every user needs to have
their own directory, someplace they can put all of their files. But
you need to make sure they don’t fill up the entire drive with all
of their files. They should also be restricted from viewing,
changing, and running certain files and programs.”
“All of the tools and files you’ll need are probably already
installed on your computer. The file /etc/passwd needs to be
present in order for anyone to log on. Tools like useradd, chmod,
and quota (which will be covered in the following sections) are
probably also on your system already. The file /etc/fstab will also
need to be edited to allow quotas, and should already be on your
system.”