String EDitor is a command line text editor that parses a file and makes changes one line at a time and as a consequence is very powerful.  It can work with regular expressions to identify and replace text and is very quick.

# Links

* [Sed One-Liners Explained, Part I: File Spacing, Numbering and Text Conversion and Substitution](https://catonmat.net/sed-one-liners-explained-part-one)
* [Sed One-Liners Explained, Part II: Selective Printing of Certain Lines](https://catonmat.net/sed-one-liners-explained-part-two)
* [Sed One-Liners Explained, Part III: Selective Deletion of Certain Lines and Special Applications](https://catonmat.net/sed-one-liners-explained-part-three)