There’s a Lot in the Dot: Filesystem Permissions and Pathnames (Part 2)
Still deeper into the dot (.) with an dive into access permissions. Study up because there’s going to be a quiz.
Wednesday, March 24th, 2010
In the previous article we saw how the hidden directory entries named . (dot) and .. (dot dot) tie the filesystem together. Those names are hard links that reference the actual filesystem object through the index number. A directory always has at least two names: . and its given name. You can always reach the parent directory through the .. entry.
Now let’s dig into how pathnames and permissions work internally. (If you’re familiar with all of this, try the quiz at the end.)
Two Paths to the Same Place
Pathnames can confuse users, but they’re actually simple when you see how they work. A pathname gives the location of an object (a file, a directory, a socket, etc.) in the filesystem. There are two kinds of pathname: absolute (or full) and relative:
