[maya] mel get all material

NO　MEAN    
　　string $shadingEngines[]=`ls -type "shadingEngine"`;
    //string $materials[]=`ls -type "material"`;
    string $ShaderS[];
    string $lambertS[]=`ls -type "lambert"`;
    string $phongS[]=`ls -type "phong"`;
    string $materials[]=`ls -sl`;

//ANSWER
string $allMaterials[] = `ls -materials`;

    for($mtl in $allMaterials)
    {
      string $materialsType=`objectType $mtl`;
      print("$mtl= "+$mtl+" $materialsType="+$materialsType+"\n");
    }