Berkeley DB (libdb) is a programmatic toolkit that provides embedded database support for both traditional and client/server applications. It includes b+tree, queue, extended linear hashing, fixed, and variable-length record access methods, transactions, locking, logging, shared memory caching, database recovery, and replication for highly available systems. DB supports C, C++, C#, Java, PHP, and Perl APIs. It supports key-value pair (NoSQL), SQL, and Java Object formatted data. It is available for a wide variety of Unix platforms as well as QNX, Android, Mac OS X, and several varieties of Windows.
GNU Wget is a utility for noninteractive download of files from the Web. It supports HTTP and FTP protocols, as well as retrieval through HTTP proxies. It can follow HTML links, download many pages, and convert the links for local viewing. It can also mirror FTP hierarchies or only those files that have changed. Wget has been designed for robustness over slow network connections; if a download fails due to a network problem, it will keep retrying until the whole file has been retrieved.
GKrellM is a GTK-based stacked monitor program that charts SMP CPUs, disks, load, active net interfaces, and internet connections. There are also builtin monitors for memory and swap, file systems with mount/umount feature, mailbox checking including POP3 and IMAP, clock/calendar, laptop battery, sensors (temperatures, voltages, and fans), and uptime. It has LEDs for the net monitors and an on/off button and online timer for PPP. There is a GUI popup for configuration, plugin extensions can be installed, and many themes are available. It also features a client/server monitoring capability.
ADODB is a set of advanced PHP database abstraction classes. It supports MySQL, PostgreSQL, Interbase/Firebird, Informix, Sybase SQL Anywhere, Oracle, MS SQL 7 and 2000, SAP DB, Sybase, DB2, FrontBase, Foxpro, Access, Netezza, LDAP, ODBTP, ADO, and generic ODBC. A metatype system is built in, making it possible to figure out that types such as CHAR, TEXT, and STRING are equivalent in different databases. It also features portable database creation, database-backed session support (with encryption), SQL performance monitoring, and database health checks.
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.
GNU TeXmacs is a free wysiwyw (what you see is what you want) editing platform with special features for scientists. The software aims to provide a unified and user friendly framework for editing structured documents with different types of content: text, mathematics, graphics, interactive content. TeXmacs can also be used as an interface to many external systems for computer algebra, numerical analysis, and statistics. New presentation styles can be written by the user and new features can be added to the editor using Scheme.
GNU Make examines the timestamps on a set of interdependent files, and, if necessary, issues commands to bring them up-to-date. The user creates a makefile describing the files, their relationships, and the commands to run. Most often make is used to rebuild libraries and programs when their sources are changed, but it can be used for any situation where one set of files needs to be generated from another set.
FLTK (pronounced "fulltick") is a cross-platform C++ GUI toolkit for UNIX/Linux (X11), Microsoft Windows, and Mac OS X. It provides modern GUI functionality without the bloat, and supports 3D graphics via OpenGL and its built-in GLUT emulation. FLTK is designed to be small and modular enough to be statically linked, and also works fine as a shared library. It also includes an excellent UI builder called FLUID that can be used to create applications in minutes.