def subparser(subparsers):
    """Define the `kevlar augment` command-line interface."""
    desc = """    Internally, kevlar annotates sequences with "interesting k-mers" and uses
    "augmented" Fastq and Fasta formats. Processing sequences with third-part
    tools usually requires discarding these annotations. This command is used
    to augment/reaugment a set of sequences using annotations from an already
    augmented sequence file.
    """
    subparser = subparsers.add_parser('augment', description=desc)
    subparser.add_argument('-o', '--out', metavar='FILE', help=
        'output file; default is terminal (stdout)')
    subparser.add_argument('augseqs', help='augmented sequence file')
    subparser.add_argument('seqs', help='sequences to annotate')
