Some example invocations:

Note how the asterisks are not expanded inside the shell because of the quotes

out/Debug/skpdiff -p \
                  "/usr/local/google/home/zachr/Downloads/gm/*_8888.png" \
                  "/usr/local/google/home/zachr/Downloads/gm/*_gpu.png"


out/Debug/skpdiff --differs different_pixels -f \
                  "/usr/local/google/home/zachr/Downloads/diffs/baseline" \
                  "/usr/local/google/home/zachr/Downloads/diffs/test"