What is GNU sed?
sed (stream editor) is a Unix utility that parses text and implements a programming language which can apply transformations to such text. It reads input line by line (sequentially), applying the operation which has been specified via the command line (or a sed script), and then outputs the line.
GNU sed Screenshots
GNU sed Features
GNU sed information
Comments and Reviews
Said about GNU sed as an alternative
sed has many features, great stability and a huge installed base. It is capable of very complex (and simple) text manipulations based on a single line, a block of lines. It supports standard POSIX regular expressions, providing a well-known approach to identifying areas to be replaced, edited or deleted.