MultiTail lets you view one or multiple files like the original tail program. The difference is that it creates multiple windows on your console (with ncurses). Merging of 2 or more log files is possible. It can also use colors while displaying the log files (through regular expressions) for faster recognition of what is important. It can also filter lines (again with regular expressions). It has interactive menus for editing given regular expressions and deleting and adding windows. One can also have windows with the output of shell scripts and other software. When viewing the output of external software, MultiTail can mimic the functionality of tools like 'watch'.
LCDproc is a utility to drive one or more LCD (and LCD-like) devices attached to a host. It is comprised of a server, which uses a modular device driver system to control attached displays, and one or more clients to gather data as appropriate and send screen data to the server. The included client displays a multitude of system statistics (CPU/memory/disk usage, uptime, date and time, temperature, etc.). Multiple clients can connect to the server simultaneously, and clients can set priorities on the screens they provide to influence in what order items are displayed. This facility can also be used to "pop" critical screens (such as an entry from syslog from a log-watching client). All functionality is implemented in userland. Support for many display devices and several platforms (Linux, *BSD, and Solaris at least) is included.
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.
procps is a package of utilities which includes ps, vmstat, top, w, skill, snice, pgrep, pkill, free, sysctl, pmap, uptime, and kill. These utilities report what is running, who is logged in, how long the system has been running, and what is using up memory. They can be used to kill processes and change run-time kernel configuration values.
Just For Fun Network Management System is a PHP-based network management system that features an integrated syslog, Tacacs, TFTP configuration downloading, SNMP polling, SNMP traps, journalling, auto-discovery, performance graphs (RRD), SLAs, and a lot more. It uses MySQL or PostgreSQL as the backend and works under Linux and Windows.
Ganglia is a scalable distributed monitoring system for high-performance computing systems such as clusters and grids. It is based on a hierarchical design targeted at federations of clusters. Ganglia is currently in use on over 500 clusters around the world and has scaled to handle clusters with 2000 nodes.
PushToTest TestMaker is a distributed test automation platform for application performance management and monitoring. It repurposes tests written in Selenium, soapUI, TestGen4Web, and Mozmill, and unit tests in Java, .NET, Jython, Groovy, PHP, Ruby, and Perl into functional tests, load and performance tests, and business service monitors. TestMaker is ideal for Web applications, Service Oriented Architecture (SOA) applications, Rich Internet Application (RIA using Ajax, Flex, Flash) and Business Process Management (BPM) applications.