How to apply a shader to the bumpmap and roughness map

currently, I’m using a shader for my map to use a displacement map on it

shader.fragmentShader = shader.fragmentShader.replace( '#include <map_fragment>',
#ifdef USE_MAP
float displacement = texture2D( displacementMap , vUv + scroll2.0).r;
vec4 texelColor = texture2D( map, vUv + displacement

    texelColor = mapTexelToLinear( texelColor );
    diffuseColor *= texelColor;

and I would like to use a similar shader on the roughness and bump maps, what variable would I have to set instead of diffuseColor?
also just checking, I replace roughnessmap_pars_fragment and bumpmap_pars_fragment correct?

I used .replace() just for roughness_map (not for parameters) here: