Rmollib is a library for manipulating molecules and systems of molecules stored in pdb, gro, and pdbz files. It gives you access to molecules on the atomic, molecular, or system level. The system can be edited in memory and then dumped to disk. It is meant for use with tool such as gromacs, Gaussian, and ToFeT. Rmoltools is a collection of command line tools that use Rmollib to manipulate and edit pdb and gro files. You may find them useful, but they principally serve as an example of how to use Rmollib.