"Linux's venerable file and user permissions system is solid and
dependable, but not very flexible, unfortunately. For users to
share access to a particular document or resource, they must all be
in the same group. It's an all-or-nothing deal, as all users within
a group have all the same rights, which is most inconvenient when
you wish to exclude someone, or include someone only on a limited
basis.
"Plus it's tedious to create a new group simply to share a
document, printer, or directory. In time, you can end up with
zillions of groups and no idea of what is going on, which, as many
admins can attest to, inevitably results in turning to drink and
life quickly going to heck in a handbasket..."
