How do you repair cracks in a concrete slab porch?

You can purchae a bottle of liquid concrete/cement from HD or Lowes. You just squirt it in the cracks and go over it with a metal putty knife. Wait until it dries, to see if it settles, you may need to add a little more, then go over with the putty knife again until it's level with the rest of your porch. Did this on my daughters porch and worked great!

Picture, please.

I just filled the expansion joints in my concrete patio with 3/8" backer rod and concrete caulk. Smaller cracks can be filled like Chubby58 said. HD does sell a non-sag crack sealer. Here are photos of my expansion joint job. Works well for larger cracks.

Ken's advice is good.

The advice is good with the illustrations. Sakcrete and Quikrete also have sites directed toward this type of thing that can be viewed.

Thanks.