I just noticed that in the /root directory, there exists a directory with its name starting with a dash: -p in my FreeBSD box.
As much as I wanted to get rid of it, I was curious to find out what’s inside that directory.
That didn’t work. After a short while of trying many things, I figured out 2 ways to do it.
Another way (1) is to add ‘./’ in front of it:
Finally, after confirming that the ‘-p’ hold no file, it can be deleted as:
Notice that, # rmdir -p does not work though. I should have put a disclaimer on the top. I only tested this on FreeBSD, but it should also work on Linux. If you decide to follow my instruction to remove any files on your system, do it cautiously. I will not be responsible for your action ^_^.