Saltar provides an overview of redirection and three commonly used command line tools in a nice article at Ars Technica. While these may seem like esoteric utilities, they can be truly useful for a variety of data cleaning and processing tasks. While the article doesn’t provide a comprehensive overview of the commands — it would be impossible to do so in anything short or readable — it does help one understand how the commands work and how they can be used. A recommended, quick read and longer-term reference. (h/t sixcolors.com)