aria2 is a utility for downloading files. The supported protocols are HTTP(S), FTP, BitTorrent, and Metalink. It has a powerful segmented downloading ability, downloading a file from multiple sources and multiple protocols and utilizing your download bandwidth to the maximum. It supports downloading a file from HTTP(S)/FTP and BitTorrent at the same time, while the data downloaded from HTTP(S)/FTP is uploaded to the BitTorrent swarm. Using Metalink's chunk checksums, aria2 automatically validates chunks of data while downloading a file like BitTorrent.
libextractor is a library used to extract meta-data from files of arbitrary type. It is designed to use helper-libraries to perform the actual extraction, and to be trivially extendable by linking against external extractors for additional file types. The goal is to provide developers of file-sharing networks, file managers, and WWW-indexing bots with a universal library to obtain meta-data about files. It includes a shell-command and bindings for Java (JNI) and Python.
BitTorrent is a tool for copying files from one machine to another. FTP punishes sites for being popular. Since all uploading is done from one place, a popular site needs big iron and big bandwidth. With BitTorrent, clients automatically mirror files they download, making the publisher's burden almost nothing.
MLdonkey is a multi-platform, multi-network peer-to-peer client. It supports several large networks such as eDonkey, Overnet, Kademlia, Bittorrent, Gnutella (Bearshare, Limewire, etc.), Gnutella2 (Shareaza), or Fasttrack (Kazaa, Imesh, Grobster). Networks can be enabled or disabled. Searches are performed in parallel on all enabled networks. For some networks, each file can be downloaded from multiple clients concurrently.
Find Duplicate Music Files detects music files that contain the same music, even if the files are differently named, and are in different formats such as MP3, OGG, WAV, WMA, M4A, and RealAudio and contain different or non-existent meta-information such as ID3 tags. The program operates on whole directories of music files, analyzes them, and outputs the filenames of pairs that seem similar, based on their audio fingerprint or perceptual hash.
aMule is short for "all-platform eMule-like file-sharing program", or, in short, "all-platform Mule". It's a port of the well-known eMule P2P client for the eDonkey2000 and Kad file sharing networks, supporting most of eMule's features. Additionally, it provides a small separate Web server and command line interface to connect to a running aMule via the network.
cfv is a utility to both test and create .sfv (Simple File Verify), .csv, .crc, .md5(sfv style), md5sum, BSD md5, sha1sum, and .torrent checksum verification files. It also includes test-only support for .par and .par2 files. These files are commonly used to ensure the correct retrieval or storage of data.