mp3dup looks for duplicate files in recursively searched directories. It is written to check for duplicate MP3 files, but can be used to find duplicate files of any type. It can told to find files that have completely identical contents, to find files that start or end with identical data, or to find files with the same ID3-tag.
GSTP is a binary file transfer protocol that focuses on security and anonymity. It tries to do right, where FTP does wrong, especially when it comes to firewall and user/password security. GSTP is based on TLS/SSL and the GSTP package includes a reference client (CLI), a QT GUI client (X11 and Win32), and a server for Unix platforms.