I don't really use a file to sharpen anything, unless it has no edge at all and I need to make one from scratch. I use DMT diamond plates - with water.
I have a toolbox full of every kind of sharpening stone imaginable, but I only use 4 tools, really and they will get anything sharp.
8" X 3" diasharp Coarse
8" X 2" duosharp fine x extra fine
Strop
Loupe Magnifier
DMT also makes an extra coarse plate, which would be good for completely re-profiling edges, or making bevels where there are none, but I don't have one and haven't really needed it.