Line editor
<tool, text> 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.
