sed & awk (Nutshell Handbooks)

For people who create and modify text files, "sed and "awk are power tools for editing. Most of the things that you can do with these programs can be done interactively with a text editor. However, using "sed and "awk can save many hours of repetitive work in achieving the same result. To master "sed and "awk you must thoroughly understand UNIX regular expressions, and understand the syntax of "sed and "awk commands. This handbook treats regular expressions as a foundation for learning about "sed and "awk and contains a comprehensive treatment of "sed and "awk syntax. It emphasizes the kinds of practical problems that "sed and "awk can help users to solve, with many useful example scripts and programs.