Whether you're cutting egg shells or glass, submerge the object under water while you cut.

The water will dampen any vibration induced by the cutting tool and prevent shattering.

You will, of course, have to either use hand tools or use a Dremel tool with an extension cable so you don't risk electric shock but, if you can figure out a way to do this, it will work. I have done it. Done carefully, you can even cut a pane of thin glass with a large pair of scissors.

Just make sure that everything, the glass and the tool, are completely submerged in water.

The question I have about using a light bulb is that it's transparent/translucent. You'll have to put the bulb inside a light tight container.

You could cut the appropriate aperture in the side of the light bulb then slide it into a cardboard tube with the correct pinhole. I think that will work. Otherwise, you could paint the outside of the light bulb with a heavy coat of black paint. But then, you would have to worry about getting the paint off the bulb.

...Unless you like the idea of turning the light bulb into a "dark bulb."