"Linux filesystem permissions and pathnames can cause lots of
confusion. Users type long pathnames when a short one would do as
well, and set wide-open access permissios when a more-secure
setting would be easy if the concepts were more clear.
"This article and the next take a unique approach: understanding
the dot (.) that you’ve probably seen in directory
"What’s “in” a directory
"Linux filesystems hold files and other objects (e.g. symbolic
links, devices like disks, and directories) grouped into
directories (known as folders on other operating systems).
It’s important to understand that a directory doesn’t
actually contain the objects; it holds references to those objects.
The references are called hard links."