Design rule checking (DRC) is an important step in the physical design flow that checks if a design meets the manufacturing constraints or design rules imposed by the process technology. It allows the foundry to ensure high acceptable manufacturing yield. Design rule verification is one of the most challenging steps because of the sheer size of the rule decks and the lack of standardization among these design rule manuals (DRMs). One way of efficiently discovering missed rule checks is by comparing the rule deck with that of another mature or well-established process. In this work, we develop two complementary techniques for comparing process design rule decks and automatically establishing a one-to-one correspondence between rules from two different process design kits (PDKs). The first approach, random layout generation (RLG), creates random layouts of different shapes and sizes. The generated layout is checked using both rule decks. The rules are then matched based on the violations generated. The second approach, based on rule language processing (RLP), matches rules based on the similarity between rule commands. Rules are directly matched based on the layer names and keywords present in the DRC commands. The two approaches are complementary and together they can correctly match more than 80% of the rules in two DRMs.