Version II.0, February 1979
This introduction describes the idea behind the Editor,
and is the first section. The second section is a tutorial for
the novice. While the Editor is designed to handle any files, the
tutorial section uses a sample program to demonstrate how to use the
most basic commands to modify a file. The third section contains a
detailed description of each command, with examples, and the fourth is
a quick reference guide.
The Concept of a ‘Window’ into the File
The Screen Oriented Editor is specifically designed for use with Video Display Terminals. On entering any file, the Editor displays the start of the file on the second line of the screen. If the file is too long for the screen, only the first portion is displayed. This is the concept of a ‘window’. The whole file is there and is accessible by Editor commands, but only a portion of it can be seen through the ‘window’ of the screen. When any Editor command takes the user to a position in the file which is not displayed, the “window” is updated to show that portion of the file.
The Cursor
The cursor represents the exact position in the file and can be used to move to any position. The window shows that portion of the file near the cursor. To see another portion of the file, move the cursor. Action always takes place at the cursor. Some of the commands permit additions, changes or deletions of such length that the screen cannot hold the whole portion of the text that has been changed. In those cases, the portion of the screen where the cursor stopped is displayed. In no case is it necessary for the user to operate on portions of the text not seen on the screen, but in some cases it is optional. In this document, examples are shown in uppercase, the cursor is denoted by an underline or lower case character.
The Concept of a Prompt Line
The Editor displays a prompt line as a reminder to the user of the current mode and the options available for that mode. Only the most commonly used options appear on the prompt line as the following display shows:
>Edit: A(djust C(py D(lete F(ind I(nsrt J(mp R(place Q(uit X(chng Z(ap[E.6]
The notation used in this section corresponds to the notation used to prompt the user in the editor. Any input that is enclosed between a < and > is requesting that a particular key be used, not that the particular word be typed out. For example, <ret> means that the return key should typed at that point. When a particular sequence of key strokes is required they will be contained within quotes. For example, “FILENAME”, <ret> refers to the typed sequence “FILENAME” followed by typing the return key. Lower or upper case may be used when typing Editor commands.
Environment
In order to establish the correct environment, depending on whether text or a program is to be edited, see the options available under Environment in the Miscellaneous commands section.
