Source : Free On-Line Dictionary of Computing

line editor
     
         An early kind of {text editor} suited to use on a
        {teletype}.  The user enters editing commands which apply to
        the current line or some given range of lines.  These include
        moving forward and backward through the buffer, inserting and
        deleting lines, substituting a string for a pattern match, and
        printing lines.  Visual feedback is restricted to explicitly
        requesting the display of one or more lines, in contrast to a
        {screen editor}.
     
        {ed} is {Unix}'s line editor.
     
        (1999-03-01)