Jesus, I hate people on this Website. Why are people so freaking stupid on here as to not give a correct answer, but instead feel like giving condescending responses?
I think the command you want is: rm -rf *
I think that rm -rf .* works on hidden files too? Not sure.
But MAKE SURE you are in the current directory you want to run this from. In other words, type pwd or echo $PWD to make sure....
So yep, that will remove all files within the current directory.
I am also certain rm -rf ../* will work, since I have tested that. You can add as many parent directories ("../") as you wish to that.
So basically, just add a "splat" on the end to bypass the stupid security.