Wait, what?
Is he saying symlinks are bad?
I like symlinks.
What happens if you move a symlink? Will it still point to the same object? That depends on whether it's relative or absolute. What if you move the directory containing it? Do you have to recursively check for the correctness of links every time you operate on a directory? Sounds unreasonable to me... What if it links to a location which isn't mounted? Whats the definition of '..'? If you cd into a linked directory and do an 'ls ..', should that list the parent of the target or the link? How would you implement that?
The point is, symlinks are a messy kluge which probably wasn't thought out very well. You can look at what Rob Pike has to say about it himself on http://cm.bell-labs.com/sys/doc/lexnames.html
You have file at /some/path, then you put newer version of that file to /some/path, replacing the old file, and the symlink still points at the same address, and it doesn't matter what actually happened with the file itself.
It's useful enough to warrant its own abstraction.
What you mean to say here is that it was a DAG and now it's a directed graph.
Note that the history shows up in the ln command which originally only created hard links, and then got the -s parameter when symlinks were introduced.
Symlinks may be ugly and/or dangerous relative to the original file system concept, but they solve problems. They are not "all good", but life would be worse without them. E.g. - application by application implementation of location aliases a la IIS virual directories (or whatever they called it) for web applications.
ADDED: Note that I avoided hard links after that, because I was worried about what would happen if I modified one file and deleted it, thinking it was a link to another, when it was actually a copy. A person could lose a lot of work if that happened. At least with a symlink, I know that something is or is not a link.
Every command that operates on files needs an extra flag to tell it whatever it should follow symlinks, or operate on the target, or on the symlink itself, etc.
>Symbolic links make the Unix file system non-hierarchical, resulting in multiple valid path names for a given file. This ambiguity is a source of confusion, especially since some shells work overtime to present a consistent view from programs such as pwd, while other programs and the kernel itself do nothing about the problem.
etc etc.
filesystems are a mess, and it'd be great if something could fix them.
And he has earned the right to do so.
(that is, not only "not having anything like them").