One of the commands the base and the main operating system, Unix-like. The name of this recipe from the combined stream editor that has come to mean the editor stream. This text command input, to analysis (processing) and makes the implementation of a programming language, text input to the text with the structure of the desired user conversion. The command text input, line by line (for sequential) reads and the changes necessary that through the command line (or by script sed) to the recipe given is the text applies and then line (lines) output. The recipe Lee. McMahon at Bell Labs in the years 1973 to 1974 for the operating system Unix already wrote that in most operating systems is available.