TCPWebLog is a system that collects and aggregates Apache and Varnish Web server logs from multiple Linux computers. It uses a simple "client" program that pipes logs to a central server over a TCP connection, and a "server" program that receive the logs and quickly aggregates or splits them.
zlog is a reliable, efficient, thread safe, flexible, pure C logging library. It was written because there were no good C logging libraries along the lines of Logback for Java or log4cxx for C++. printf can work, but can not be easily redirected or reformatted, and syslog is slow and designed for system use. It provides a syslog model, log format customization, multiple output, safe run-time reconfiguration, high performance, user-defined log levels, safe log rotation, a log4j-style key-value map, in-built debugging, and no external dependencies.
OtrosLogViewer (OLV) is software for analyzing an application's logs and stack traces. It loads logs from remote servers using ftp, sftp, ssh, samba and other supported filesystems, listening on a socket, or connection to a Log4j SocketHubAppender. Logs can be gzipped, and OLV will decompress them on the fly. Many log formats are supported (JDK logging, Log4j XML, and custom patterns). OLV allows log highlighting. Automatic log highlighting is based on string matches, regular expressions, or custom Java code. Notes can be added to log events. Display of message details can be customized by message formatters and a colorizer (i.e., formating SOAP request and highlighting XML syntax). OLV can be extended by plugins (filters, log parsers, log event markers, message detail formatters, and colorizers).
Analog PHP is a short and simple logging package for PHP 5.3+ based around the idea of using closures for configurability and extensibility. It functions as a static class, but you can completely control the handling of log messages through closures (aka anonymous functions), and it also comes with a dozen pre-written handlers. It is well-documented, with examples for each type of log handler, and ultra-concise. The core is literally only 43 lines of clear, non-obfuscated code, and the whole is only a fraction of the size of comparable packages (for example, 293 total lines vs 1021 for Monolog).
Ipt_fw is a firewall for Linux based on iptables. It is designed for client systems. Ipt_fw outputs a shell script containing iptables commands, so inspection of the settings it creates is easy. The configuration files are made in LibreOffice（OpenOffice）Calc. Making of the firewall and a machine using the firewall are separated. It allows you to set the user level and features detailed logging, IP address blacklist management, and iptables integrity.
python-tracing provides the Python library "tracing" to help with logging debug messages. This module provides a couple of functions for logging debug messages. It is sometimes practical to add a lot of debugging log messages to a program, but having them enabled all the time results in very large log files. Also, logging that much takes quite a bit of time. This module provides a way to turn such debugging or tracing messages on and off, based on the filename in which they occur.
pam_ttylog is a PAM module to log console output of a login shell. pam_ttylog takes an approach that makes a script-like environment in the PAM session section of /bin/login. Thus, the log files are in a user-unreachable directory and have user-unreadable/unwritable permissions. As PAM module, it doesn't need to modify or replace the original /bin/login, getty, telnet, or libraries for its installation and operation.
jmxtrans is effectively the missing connector between JMX and whatever logging or graphing package that you can dream up. jmxtrans is very powerful tool that reads JSON configuration files specifying servers/ports and JMX domains/attributes and then outputs the data in whatever format you want via special "Writer" objects that you can code up yourself. It does this with a very efficient engine design that will scale to querying literally thousands of machines. The core engine is pretty solid and writers are included for cacti/rrdtool, graphite, and stdout.