<P> Line editors are still used non-interactively in shell scripts, and TECO (see below) can be used in much the same manner, albeit with more features . Patch systems such as patch (Unix) traditionally used diff data that was a script of ed commands . They are also used in many MUD systems, though many people prefer to edit text on their own computer and then use their MUD client's upload feature to paste the text directly in the line editor . </P> <P> While TECO is sometimes incorrectly considered a line editor, it is in fact modal and character - oriented . In non-technical terms, it's perhaps best described as a modern editor in the tradition of Vim running with the document out of view . Line commands are understood as searching for the two - character string "(CR) (LF)", and the insertion point may in fact be positioned between these two characters . Because the PDP - 6 used a modified IBM Selectric as a printer, and because the Selectric used physical movements of the platen and carriage to print text, boldface, strikethrough, and underscore were all possible by omitting either the (CR) or (LF). Below is an example of TECO showcasing special text effects and its character - oriented nature; note that the asterisk is TECO's input prompt, and dollar signs stand for a press of the Escape key . </P> <P> Superficially, this looks much like a line editor session; it is important, however, to note that the next - line command (l) actually means move to position following next consecutive CR LF, that this position is the number of characters from the start of the file, and that if the user knew the position, he could manually jump to it with the jump (j) command . </P> <P> The last two commands issued (zj and k) are shorthand for "jump to final position" and "kill line". They, or their direct equivalents, are useful to disambiguate between a line editor and a character - oriented editor . On a line editor, these would have the expected effect, i.e. that of deleting the final line of the file . On TECO, the command fails, because it sees a line as "a string of text terminated by consecutive CR LF"; in its eyes, the "last" line would in fact be the penultimate . </P>

Difference between line editor and screen editor in unix