This script finds interface residues between two proteins or chains, using the following concept. First, we take the area of the complex. Then, we split the complex into two pieces, one for each chain. Next, we calculate the chain-only surface area. Lastly, we take the difference between the comeplex-based areas and the chain-only-based areas. If that value is greater than your supplied cutoff, then we call it an interface residue.
interfaceResidue complexName[, cA=firstChainName[, cB=secondChainName[, cutoff=dAsaCutoff[, selName=selectionNameToReturn ]]]]