fs.open(...,"w") How to delete?

Hi everyone!
When I experimented with FS API I've got a problem *again*. When I create file from function

fs.open(string,"w")

I can't delete it. How I can do it?
Sorry for my bad english

fs.delete(filename).

But you have to close your file handles. fs.open() returns a file handle, which you have to catch to a variable, ex:

file=fs.open("derp","w")

then you have to close that handle when you're done writing to it

file.close()

otherwise the file is left open, and therefore can't be deleted, because it's open. In the latest versions, rebooting the computer that opened it seems to close it, allowing the file to be deleted, though I think there were issues with this in earlier versions of CC.

Thank you! Rebooting helps me.