Question

Which of the following commands is known as stream editor?

(a) sed

(b) grep

(c) grep

(d) tr

I had been asked this question in an internship interview.

My question is based upon sed command topic in section Filters using Regular Expressions of Unix

Answer 1

The correct answer is (a) sed

To elaborate: sed is a multipurpose tool which performs the function of several filters together. This filter is derived from the ed (original UNIX editor). It performs non-interactive operations on a data stream.  It uses instructions to act on a text for selecting lines, with an action to be taken.