Logdog is a tool that monitors messages passing through syslogd and takes action based on key words and phrases. Logdog has an easy to read configuration file which allows you to specify a list of key words or phrases to alert on, and a list of commands that can be run when those words are encountered. Logdog has been featured in magazines and deployed in production networks all over the world. It sorts features like no-delay message interception for low latency alerts, comprehensive logging and debugging, proper HUP signal handling, and regular expressions for complex pattern matching.