log4bash facilitates creating easy to read and easy to parse log files from your bash scripts. Developers have the ability to override pretty much all of the default behavior. If the developer chooses to let a user do so, they can pass flags to a script at run time to control some aspects of the logging output. This includes displaying the logging output to the screen in addition to the log file, and altering the logging level. There is a script included (test.log4bash.sh) that provides working code on how to use all of log4bash's features.
n2 is a client/server system for transmitting forensic snapshots from a number of hosts to a receiver node. This receiver collects statistics and is able to present an overview of the current and historical situation on a server. n2 provides a robust solution for real-time monitoring, optimizing performance, and analyzing crashes.
s6-portable-utils is a set of tiny general Unix utilities, often performing well-known tasks such as cut and grep, but optimized for simplicity and small size. They were designed for embedded systems and other constrained environments, but work everywhere. Other sets of small utilities are usually system-specific; for instance, the (otherwise excellent) BusyBox project only works on Linux.