dat is similar to ipfs, p2p file sharing. Earlier dat's goal was to allow sharing and versioning of tabular data(csv), json. dat alpha was more about syncing non tabular files, single centralized repository like Dropbox. you can read here more about how dat evolved.
Current api 1.0 has only two commands dat link and dat <share-link>. The debug flag prints more output like bittorent-dht node queries.
Unlike ipfs dat sha256 hash also considers file modes(permissions) among the other filesystem metadata. Dat uses a variety of different methods to discover peers that have the data it's looking for, including DNS, Multicast DNS, UDP, and TCP. Like ipfs it also has bootstrap nodes.
Key differences to BitTorrent
Although file sharing using Hyperdrive on the surface could seem similar to tools such as BitTorrent there are a few key differences.
Not all metadata needs to synced up front
BitTorrent requires you to fetch all metadata relating to magnet link
from a single peer
before allowing you to fetch any file content from any other peer. This
also makes it difficult to share archives of 1000s of files using
Flexible and consistently small block sizes
BitTorrent requires a fixed block size that usually grows with the
size of the content you are sharing.
This is related the above mentioned fact that all metadata needs to be
exchanged from a single peer before any content can be exchanged. By
increasing the block size you decrease the number of hashes you need to
exchange up front. Flexible block sizes also allow for more non file
related use cases, such as the file metadata feed described above.
BitTorrent inlines all files into a single feed. This combined with
the fixed block sizes makes deduplication hard and you often end up
downloading the same files multiple times if an update to a torrent is
Unlike BitTorrent, wires can be reused to share multiple swarms which
results in a smaller connection overhead when downloading or uploading
multiple feeds shared between two or more peers.
Good read, documentation 
and the dependencies