Organization of Webpages
In this page, we describe a few simple operations and commands to get a user started on basic text editing. Subsequently, each of the operations and commands of IVI will be described in full. Generally these descriptions will be organized by topic. Thus, the commands which store and retrieve files will appear in one page, those which search for strings and patterns in another, and so on.
For operations we give a short name, a brief description (Purpose), the default key which invokes it, and some detailed notes. We also give the operation number, which is important only if you wish to reassign the operation to a different key.
For commands, we give the command name, a brief description, a list of the parameters, some detailed notes, and often some examples. In general, we write the name of the command with its first two letters capitalized: FEtch, these being the letters which are typed to enter the command.
Basic Text Editing
As we noted in the Introduction, text is typed simply by moving the cursor around the text zone while in TYPING/INSERT mode, and typing displayable characters. Characters are entered at the cursor position, and existing characters are either overtyped or shifted to make room, depending on the submode (TYPING or INSERT).
The cursor is moved using the four "arrow" keys, which we will refer to as <left>, <right>, <up> and <down>. If the cursor is moved past the edge of the text zone, the text is moved appropriately to display a different portion. (In the up and down directions, the text "scrolls"; in the left and right directions, it shifts to an overlapping area. No shift takes place beyond the original first column.)
Characters (and blank lines) may be deleted with the <DEL> key. A blank line can be inserted following the cursor line using <CTRL F>.
To save a file, you enter COMMAND mode (using <CTRL C>) and type the command:
(Remember to type only the letters SA for the command; the command name will be completed by IVI.)
This command only works if somefilename does not already exist. If it does exist you will get the message:
File already exists (or no write permission)
Either <DEL> or <RETURN> will remove the error message and allow you to make a different choice. Similarly, the command:
will allow you to replace an existing file with an edited version, but only works if the file DOES already exist. (This is an attempt to minimize carelessness on the part of the user. The user must choose the correct one of the two commands.) The OVerwrite command can also produce another message:
Check name, not file fetched
This one is a warning, not an error message. <DEL> aborts the command; <RETURN> allows it to proceed.
An existing file can be retrieved from disk and placed in the corefile, removing the corefile's current contents with:
As well as producing an error message if the file does not exist, this command also issues a warning:
Warning: corefile not saved
if the contents of the corefile have not been SAved or OVerwritten since the last change was made to it. You may then proceed with typing the filename and execute the command, or abort it with <DEL>.
Finally, the command:
exits from IVI, though before doing so it may produce several messages of the form:
WARNING: corefile 1 not saved. <DEL> aborts
one for each corefile which has been changed but not SAved or OVerwritten. <RETURN> allows the command to continue (perhaps producing another such message.)