There are two groups of receivers particularly interested in your application logs: human beings (you might disagree, but programmers belong to this group as well) and computers (typically shell scripts written by system administrators). Logs should be suitable for both of these groups. If someone looking from behind your back at your application logs sees: from Wikipedia then you were probably not reading my tips carefully enough. The reference to famous Clean code book in the title of this series is not accidental: logs should be readable and easy to understand just like the code should. On the other hand, if your application produces half GiB of logs each hour, no man and no graphical text editor will ever manage to read them entirely. This is where old-school grep , sed and awk come in handy. If it is possible, try to write logging messages in such a way, that they could be understood both by humans and computers, e.g. avoid formatting of numbers, use patterns that can be e