op.add_option("--pname", "--pfile", dest="PNAME", default="params.dat", help="Name of the params file to be found in each run directory (default: %default)")
op.add_option("--wfile", dest="WFILE", default=None, help="Path to a weight file, used to restrict plotting to a subset of histograms (default: %default)")
op.add_option("-o", "--outdir", dest="OUTDIR", default="envelopes", help="Output folder for plots (default: %default)")
op.add_option("-v", "--debug", dest="DEBUG", action="store_true", default=False, help="Turn on some debug messages")
op.add_option("-q", "--quiet", dest="QUIET", action="store_true", default=False, help="Turn off messages")