Utility functions that may be of general interest but are specifically required by the 'NeuroAnatomy Toolbox' ('nat'). Includes functions to provide a basic make style system to update files based on timestamp information, file locking and 'touch' utility. Convenience functions for working with file paths include 'abs2rel', 'split_path' and 'common_path'. Finally there are utility functions for working with 'zip' and 'gzip' files including integrity tests.