curl and libcurl is a tool for transferring files using URL syntax. It supports HTTP, HTTPS, FTP, FTPS, SCP, SFTP, TFTP, DICT, TELNET, LDAP, POP3, IMAP, SMTP, RTSP, RTMP, and FILE, as well as HTTP-post, HTTP-put, cookies, FTP upload, resumed transfers, passwords, port numbers, SSL certificates, Kerberos, and proxies. It is powered by libcurl, the client-side URL transfer library. There are bindings to libcurl for about 40 languages and environments.
Gow (GNU On Windows) is a lightweight alternative to Cygwin. It uses a convenient Windows installer that installs about 130 extremely useful open source Unix applications compiled as native Win32 binaries. It is designed to be as small as possible, about 10 MB, as opposed to Cygwin which can run well over 100 MB depending upon options.
GraphicsMagick is a robust collection of tools and libraries which support reading, writing, and manipulating an image in over 90 major formats including popular formats like DPX, DICOM, BMP, GIF, JPEG, JPEG-2000, PDF, PNG, PNM, SVG, and TIFF. A high-quality 2D renderer is included, which provides a subset of SVG capabilities. C, C++, Perl, Tcl, and Ruby are supported. Originally based on ImageMagick, GraphicsMagick focuses on performance, minimizing bugs, and providing stable APIs and ABIs. It runs on all modern variants of Unix, Windows, and Mac OS X.
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.
Launch4j is a cross-platform tool for wrapping Java applications distributed as jars in Windows native executables. The executable can be configured to search for a certain JRE version or use a bundled one, and it's possible to set runtime options, like the initial/max heap size. The wrapper also provides better user experience through an application icon, a native pre-JRE splash screen, and a Java download page in case the appropriate JRE cannot be found. The increase in size of the application is small.
bitstring is a Python module that helps to make the creation and analysis of binary data as simple and natural as possible. Objects can be constructed from integers (big and little endian), floats, hex, octal, binary, byte data, iterables, or files. They can be sliced, joined, reversed, packed, unpacked, inserted into, overwritten, and otherwise operated upon with simple functions or slice notation. They can also be parsed, searched, and navigated in, similar to a file or stream. Internally the data is efficiently stored as byte arrays. It is available for Python 2.6 and later (including Python 3).