File::Spec is definitely The Right Way™ to do this, because it is both purposeful and portable.   You really don’t want to have to be mucking-around with slashes, do you?   Worrying whether they ought to be forward or backward on this system or that?   Naww-w-w-ww, not if someone else has already done it for you!   And, since it is in the Core, you don’t have to install it:   it is already there.