I've been admining Linux systems for 25 years, and I still have to check which one it is every time.
Firstly, plain "ln" without "-s", and not crossing file system boundaries, is like "mv" without the remove part. You end up having the same file twice, in two directories, or different names in the same, symmetrically, no original and no copy. Doesn't work on directories, though.
Secondly, "ln -s" is like "ln", only the result is not symmetric, but then, it may cross file system boundaries and point to directories.
So if you remember how to use mv, you're fine.
@dj3ei @hennichodernich @monsieuricon
Yeah `mv` is kind of the Star Trek teleporter, and `ln` one of those episodes where you wind up with two of someone.