How do I copy a hierarchical module in KiCAD?

If you have many same schematic blocks you want to reuse, you can use hierarchical sheet like this: (Kicad-4.0.2-stable MacOSX)

1. Create a hierarchical sheet with sheet name A_1 , file name A.sch
2. Place your components and wires into this hierarchical sheet.
3. Add a new hierarchical sheet with sheet name A_x (x is 1, 2, 3), file name A.sch ( only if the file name is the same, but different sheet name will work)
4. Done.

This is an old question I know, but it's what I found when searching for a solution to this problem, so I think it's a good place to put the solution for fellow searchers:

1. Drag a box around around the sheet you want to duplicate, using the left mouse button.
2. Release the left mouse button and press the right to see a menu of things you can do. Select "Save Block".
3. Then click on the little clipboard (paste) icon which will be somewhere around the edge of your schematic editing area (it's near the top left for me).
4. Select where the new block will go.

This will paste a copy of your block, but it will refer to a new sheet based on the same filename as the original. If you annotate parts you'll see that the parts in the different sheets have different labels, even though they are sourced from the same schematic file.

Create your hierarchical sheet. Then, press "Space". It will look like it is in the image below, but you can move it anyways with "M" key, or right clicking and then clicking "Move Sheet".

I do not remember if this is the default hot-key for "Repeat Last Item" or if I have changed it before. To check this, go to Preferences>Hotkeys>List Current Hotkeys.