Sed 4.2.1

Sed - Stream-oriented non-interactive text editor.

Sed (streams editor) isn't really a true text editor or text processor. Instead, it is used to filter text, i.e., it takes text input and performs some operation (or set of operations) on it and outputs the modified text. Sed is typically used for extracting part of a file using pattern matching or substituting multiple occurances of a string within a file.