A link is a directory entry referring
to a file; the same file (together with
its size, all its protection
may have several links to it.
There is no way to distinguish a link to a file
from its original directory entry;
independently of the name by which the file is known.
creates a link to an existing file
is given, the link has that name;
otherwise it is placed in the current directory
and its name is the last component
It is forbidden to link to a directory
or to link across file systems.