Lynis is an auditing and hardening tool for Unix derivatives like Linux/BSD/Solaris. It scans systems to detect software and security issues. Besides security-related information, it will also scan for general system information, installed packages, and possible configuration mistakes. The software is aimed at assisting automated auditing, software patch management, and vulnerability and malware scanning of Unix-based systems.
MailScanner is an email virus scanner, vulnerability protector, and spam tagger. It supports the Postfix, Sendmail, Exim, Qmail, and ZMailer MTAs, and the Sophos, McAfee, F-Prot, F-Secure, CommandAV, InoculateIT, Inoculan, eTrust, Kaspersky, Nod32, AntiVir, BitDefender, RAV, Panda, DrWeb, ClamAV, and other anti-virus scanners. It uses SpamAssassin for highly successful spam identification, and is designed to handle denial of service attacks. It will detect password-protected zip files and apply filename checking to their contents. It is very easy to install, requires no changes at all to your sendmail.cf file, is designed to be lightweight, and won't grind your mail system to a halt with its load. It can be integrated into any email system, regardless of the software in use.
The MirBSD Korn Shell (mksh) is an actively developed successor of pdksh (the Public Domain Korn Shell), aimed at producing a shell good for interactive use, but with the primary focus on scripting. It is intended to be portable to most *nix-like operating systems as long as they're not too obscure. mksh incorporates improvements from OpenBSD and Debian, as well as bugfixes and enhancements developed for the MirOS, FreeWRT, and MidnightBSD projects and Android. The emacs command line editing mode is UTF-8 capable, and Byte Order Marks are ignored in scripts. The shell supports large files, as well as all pdksh and some csh, AT&T ksh, zsh, and GNU bash features, is compatible with the Bourne shell and POSIX (within limits), has no limit on array sizes, and incorporates some other useful builtins and features. While being already fast and small (without losing functionality), flags to make it even smaller can be given at compile time. An interactive shell reads "~/.mkshrc" on startup.
Munin is a system to gather and graph all sorts of information. You can install a node on the various machines in your network, as well as on a central server. The nodes will know how to extract various kinds of information, such as load average and bandwidth usage, and will wait for the server to request these values. The output is in HTML format. The server can optionally send notifications if any of the values move outside of a specified range (and when they move back into it).
OraRep is a PL/SQL snippet (embedded in a shell script) which creates a well-formatted HTML report on a given database instance, providing you with an overview on your instance(s), some hints for performance tuning, and more. It has been tested with Oracle 8.1.7, 9.0.1, and 9.2. The script easily fits into a cron task to be run on a regular basis. Sample output (HTML) is included. OSPRep does the same job for Oracle StatsPack Reports based on SnapShot Levels up to 7, and provides additional "plugins" for more detailed reporting on special issues. It also optionally creates a separate page with charts to visualize the results and more.
makeself is a small shell script that generates a self-extractable compressed TAR archive from a directory. The resulting file appears as a shell script, and can be launched as is. The archive will then uncompress itself to a temporary directory and an arbitrary command will be executed (for example, an installation script). This is pretty similar to archives generated with WinZip Self-Extractor in the Windows world.
LPAR2RRD makes historical, future trends and nearly "realtime" CPU utilization graphs of LPARs and shared CPU usage of IBM Power servers. It collects complete physical and logical configuration of all servers/LPARs. It is agent-less (it gets everything from the HMC/SDMC or IVM). It supports all kinds of logical partitions (AIX/AS400/Linux/VIOS).
bcnu is a Web-based system management tool which delivers information on the status of networked systems in a simple and easy-to-use manner. It uses a web browser to display information about hosts in a tabular form. Historical information can be held indefinitely, and there is a powerful query tool available to interrogate it. Client systems can run an agent which logs information back to a central system. An agent scheduler is integrated to allow agents to be run at different intervals. Standard agents include ftp, http, disk space, logfiles, processes, and more.