PerlMol is a collection of Perl modules for chemoinformatics and computational chemistry with the philosophy that "simple things should be simple". It should be possible to write one-liners that use this toolkit to do meaningful "molecular munging".
Open source project that offer summary and download services on this page is a project that carry out their development work on other open source development sites. Their work is linked to this page via a feature called OFI, and their work is not carried out here on OSDN site.