usage: hashset.py
                  (-b ITEM-FILE HASHSET-FILE | -d HASHSET-FILE | -p HASHSET-FILE [ITEM ...])
                  [--encoding CHARSET] [-h] [--internal-encoding CHARSET]
                  [--index-int-size N] [--item-int-size N]
                  [--load-factor FRACTION] [--pickler {pickle,string}]
                  [--hash ALGORITHM]

Build, read, and probe hashets to/from files.

Actions:
  Available modes of operations. Select exactly one of these!

  -b ITEM-FILE HASHSET-FILE, --build ITEM-FILE HASHSET-FILE
                        Build a new hash set from the lines of a file. The
                        special value '-' as a stand-in for standard input and
                        output respectively.
  -d HASHSET-FILE, --dump HASHSET-FILE
                        Write out all items from a given hash set.
  -p HASHSET-FILE [ITEM ...], --probe HASHSET-FILE [ITEM ...]
                        Probe the existence of a list of items in a hash set.
                        The item list is either the list of positional
                        command-line arguments or, in their absence, read from
                        standard input one item per line.

Optional Arguments:
  --encoding CHARSET, --external-encoding CHARSET
                        The external encoding when reading or writing text.
                        (default: UTF-8)
  -h, --help            Show this help message and exit.

Hashset Parameters:
  Parameters that influence hash set creation.

  --internal-encoding CHARSET
                        The internal encoding of the entries of the hash set
                        file to build. (default: UTF-8)
  --index-int-size N    The size (in bytes) of the integer, a power of 2, used
                        to store offsets in the bucket index. This may save
                        some time and memory during hash set construction.
                        (default: determine optimal value)
  --item-int-size N     The size (in bytes) of the integers used to store the
                        length of the (encoded) hash set items. (default:
                        determine optimal value)
  --load-factor FRACTION
                        The load factor of the resulting hash set, a positive
                        decimal or fraction. (default: 0.75)
  --pickler {pickle,string}
                        The "pickler" used to encode hash set items; either
                        'string' encoding for strings (default) or the
                        'pickle' encoding working on a wide array of Python
                        objects.
  --hash ALGORITHM      The hash algorithm used to assign items to buckets.
                        (default: xx_64)

Author and copyright: David Foerster, 2017

Source code repository and issue tracker:
https://github.com/davidfoerster/python-hashset