di is a disk information utility that displays everything that df does and more. It features the ability to display your disk usage in whatever format you prefer. It also checks the user and group quotas, so that the user sees the space available for their use, not the system wide disk space. It is designed to be highly portable across many platforms and is great for heterogenous networks.
Partition Logic is a partitioning and disk management tool for PC-compatible computers. It includes its own standalone operating system and GUI, and can fit on a single bootable floppy (or CD). It creates, modifies, resizes, deletes, formats, and moves partitions, and copies hard disks. It is based on the Visopsys operating system.
SmoothWall Express is a network firewall, designed with home and small business users in mind. It is based upon a security-hardened subset of the GNU/Linux operating system and is completely free to use, download, and distribute. SmoothWall Express offers facilities and features normally only seen in expensive commercial offerings.
HDT (Hardware Detection Tool) is an OS independent tool that displays low-level information on any x86 compatible system. It detects ACPI, CPU, PCI devices, DMI (memory, BIOS, motherboard, IPMI base board, chassis, batteries, CPU), disks (geometry, partitions), PXE environment, VESA modes, and VPD. It can also deduce the Linux kernel modules needed by a given host.
crypt_blowfish is an efficient implementation of a modern password hashing algorithm, based on the Blowfish block cipher, provided via the crypt(3) and a reentrant interface. It is compatible with bcrypt as used in OpenBSD. It is adaptable to future processor performance improvements, allowing you to arbitrarily increase the processing cost of checking a password while still maintaining compatibility with your older password hashes. The hashes it produces are several orders of magnitude stronger than traditional Unix DES-based or FreeBSD-style MD5-based hashes.
MySQL Administrator is a powerful visual administration console for MySQL, which allows the user to easily administer their MySQL environment, and gain better visibility of how their databases are operating. It is available with native GUI interfaces for Windows, Linux, and Mac OS X.
nexB OpenAssets is a tool for inventorying, managing, and monitoring applications, software, hardware, networks, and generally any IT asset. It is designed so that system administrators, IT, and finance can determine what they have, how it is configured, what it is used for, and how much it is being used, so that informed decisions can be made. It complements existing network management software, integrates with a growing number of protocols and tools, and features no-agent discovery and inventory, configuration management including dependencies and correlation, monitoring, and reporting. It makes extensive and innovative use of XML, Xpath, and Xquery.
rpl is a Unix text replacement utility. It will replace strings with new strings in multiple text files. It can scan directories recursively and replace strings in all files found. The search can be limited to files with certain filename suffixes (e.g. '.html', '.c', etc.). It includes source, a build script, and a man page. It should work on most flavors of Unix. Linux/Intel, Linux/PPC, and source RPMs are available, as are binaries for other OSes, including Mac OS X.
gnoMint is a tool for easily creating and managing certification authorities. It provides fancy visualization of all the pieces of information that pertain to a CA, such as x509 certificates, CSRs, and CRLs. gnoMint is currently capable of managing a CA that emits certificates that are able to authenticate people or machines in VPNs (IPSec or other protocols), secure HTTP communications with SSL/TLS, authenticate and cipher HTTP communications through Web-client certificates, and sign or crypt email messages.