dRep is a python program for rapidly comparing large numbers of genomes. dRep can also "de-replicate" a genome set by identifying groups of highly similar genomes and choosing the best representative genome for each genome set.
Manual, installation instructions, and API are at available at ReadTheDocs
Publication is available at ISMEJ
Open source pre-print publication is available at bioRxiv
$ pip install drep
$ dRep compare output_directory -g path/to/genomes/*.fasta
$ dRep dereplicate output_directory -g path/to/genomes/*.fasta
$ dRep check_dependencies