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- Command Overview 2-1
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- 2. COMMAND OVERVIEW
- 2. COMMAND OVERVIEW
-
- One of the nice things about EDIT is how easy it is to use. To
- create a document named memo1, the user types
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- edit memo1
-
- waits for EDIT to start executing, and then simply starts typing.
- There is no need to wade through a hierarchy of menus just to get
- started. To delete a character, the user presses the backspace key.
- To move the cursor, the user presses one of the the arrow keys on the
- right side of the keyboard. EDIT's commands are simple, and they are
- easy to use (just one or two keystrokes), but they are powerful.
-
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- 2.1. Basic Concepts
- 2.1. Basic Concepts
-
- EDIT is a program that runs on an IBM-PC compatible computer. It
- allows a user to create and edit documents containing arbitary text.
- To do this, EDIT must first be started (explained in section 2.2).
- Once EDIT is started, it allows the user to type text at the
- keyboard. As each character is typed, EDIT displays it on the CRT
- screen of the computer. The place where the character will be
- displayed is indicated by the small, blinking dash on the screen.
- This line is called the "cursor". After the character is displayed,
- the cursor moves one position to the right. When the user types the
- Enter key, the cursor moves one line down and to the left side of the
- Enter
- screen (like pressing the return key on a typewriter).
-
- EDIT also stores each character the user types in a large storage
- area in the computer called its "editing buffer", or just "buffer".
- The buffer holds many more characters than EDIT can display on the
- screen at once, so EDIT is limited to only displaying 23 lines of the
- text at any one time. When the user types more lines of text than
- will fit on the sreen, the cursor can no longer be moved down, so
- instead, all the lines on the screen are "scrolled" up one line, the
- top line disappears, and the cursor stays on the bottom line. The
- user need not worry about the line that disappears from the top of
- the screen. It is still stored in the editing buffer.
-
- EDIT also allows the user to modify the text he has typed. For
- example, when the user types the Backspace key, the character
- Backspace
- immediately to the left of the cursor will be erased from the screen,
- and the cursor will move one position to the left. In fact, all EDIT
- commands that modify the text affect only the characters immediately
- adjacent to the cursor.
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- EDIT Users Manual
- Command Overview 2-2
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- EDIT includes commands for moving the cursor around the screen. This
- allows the user to go back to characters typed previously and delete
- them, or insert new text. Whenever the user gives some cursor
- command that would move the cursor off the top or bottom of the
- screen (like the up command when the cursor is on the top line of the
- up
- screen), the screen is scrolled up or down instead, so that the
- cursor always stays on the screen. EDIT also includes commands for
- moving the cursor to any point in the text stored in the editing
- buffer. When the user gives one of these commands, EDIT will
- completely update the text displayed on the screen, so that the 23
- lines adjacent to the cursor are displayed.
-
- As explained above, EDIT stores all the text the user is editing in
- its editing buffer. However, this storage of the text is only
- temporary, while the user is running EDIT. For a more long-term
- storage of the text, the user must save it in a DOS file. EDIT
- includes commands to save text in a file and retrieve the text
- previously saved in a file. EDIT will warn a user if he attempts to
- do anything that will lose the text in the editing buffer if it has
- not been saved in a file.
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- 2.2. How to Start EDIT
- 2.2. How to Start EDIT
-
- The command to start EDIT has the following basic form:
-
- edit [ filename ]
-
- To start EDIT, this command should be entered in response to the DOS
- prompt. The brackets around "filename" indicate that the file is
- optional. The user should not type the brackets. The user does not
- actually type "filename". Instead, he should type the actual name of
- a DOS file he wishes to edit.
-
- If no file is supplied, EDIT will be initialized with an empty
- editing buffer and the message "No file specified" is displayed in
- the lower left corner of the screen.
-
- If the file already exists, it is read into EDIT's buffer and the
- cursor is positioned at the beginning of the file. EDIT displays the
- message "Editing: filename" in the lower left corner of the screen.
-
- If the file does not yet exist, EDIT is initialized with an empty
- buffer, and EDIT displays the message "Creating: filename" in the
- lower left corner of the screen.
-
- Thus, the following are several examples of how EDIT is invoked:
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- EDIT Users Manual
- Command Overview 2-3
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- edit
- edit memo.txt
- edit b:prog1.src
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- The user may also supply the name of a "setting-file" after the name
- of the file to edit. Thus, the following is the full form of the
- command to start EDIT:
-
- edit [ filename [ settingfile ] ]
-
- The setting file is used to initialize the options that effect
- editing and printing. If no setting file is specified, edit will
- look for the file "edit.set" on the default DOS device. If this file
- exists, it will be used to initialize EDIT's settings. Otherwise,
- EDIT will use its default settings, which have been designed for
- basic word processing. The setting file is explained in greater
- detail in section 3.3. Section 3.4 also explains how EDIT
- automatically looks for a setting file associated with the file
- currently being edited.
-
- The following examples show how the user may start EDIT and specify
- both a file to edit and a setting file:
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- edit prog2.c color.set
- edit letter.txt wp.set
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- 2.3. Screen Organization
- 2.3. Screen Organization
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- EDIT organizes the screen as follows:
-
- Text area: top 23 lines
- Prompt line: next to the bottom line
- Status line: bottom line
-
- EDIT uses the top 23 lines of the screen to display the portion of
- the file that contains the cursor. Lines that are longer than 80
- characters will only have their first 80 characters displayed,
- although all commands operate on long lines normally.
-
- EDIT uses the 24th line on the screen (the next to the bottom line)
- for prompts regarding the use of function keys, for input of file
- names, search strings, and such, and for messages.
-
- The bottom line on the screen displays the name of the file being
- edited and various status indicators. On the far right side of the
- bottom line EDIT displays the line and column numbers of the current
- cursor position within the file. To the left of the line and column
- numbers on the bottom line, EDIT displays the amount of free space
- currently available in its editing buffer as a percentage of the
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- EDIT Users Manual
- Command Overview 2-4
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- total space available.
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- 2.4. Command Basics
- 2.4. Command Basics
-
- Each key the user types in EDIT may be considered a command, in that
- each keystroke causes a specific action to take place, and the result
- of that action is immediately displayed on the screen. Usually this
- consists of moving the cursor, deleting a portion of text adjacent to
- the cursor, or inserting the character typed into the buffer at the
- cursor position.
-
- To avoid confusing the user, EDIT always does the same thing for all
- commands. Thus, EDIT might be called a "modeless" editor. However,
- EDIT does have different "modes" that determine what happens when a
- character is typed for insertion into the buffer. These are "Insert"
- mode and "Replace" mode. In Insert mode, each character typed is
- inserted into the text at the cursor position and the characters to
- the right of the cursor are moved over one position to make room for
- the inserted character. In Replace mode, the character typed
- replaces the character that was at the cursor position.
-
- Likewise, EDIT gives the user control over what it does when
- characters are inserted or deleted so that a line doesn't fit nicely
- between the left and right margins. This is EDIT's "Word processing"
- mode. The different options for the Word processing mode are
- explained in section 3.3, under the "Set Word processing mode"
- command.
-
- A simple set of rules for EDIT's commands is as follows. All text
- characters are simply inserted (or "replaced") into the buffer. The
- cursor control keys (Left, Home, etc.) on the right side of the
- Left Home
- keyboard generally perform some action that corresponds to the label
- on the key (Left means move cursor left, and Home means move cursor
- Left Home
- to beginning of line). In addition, each of these keys also perform
- some "stonger" version of the same command when it is given with the
- Shift key depressed (Shift-Left means move left one word, and
- Shift Shift Left
- Shift-Home means move left one sentence).
- Shift Home
-
- A similar set of rules governs the use of the 10 function keys on the
- left side of the keyboard. Each of these has a standard command
- associated with it. The help line lists each of these commands. For
- example, F9 is the command to delete a block of text and save it in
- F9
- an internal buffer from which it can later be retrieved. However,
- some of these commands also have a modified version, which is given
- by holding down the Shift key and simultaneously pressing the
- Shift
- function key. Shift-F9 is the command to delete a block of text
- Shift F9
- without saving it.
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- EDIT Users Manual
- Command Overview 2-5
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- For convenience, the user may use Alt or Ctrl instead of Shift to get
- Alt Ctrl Shift
- the modified version of the function keys on the left side of the
- keyboard.
-
- A few additional commands are obtained by pressing Alt and one of the
- Alt
- text keys in the center of the keyboard. Generally the key pressed
- with Alt is the first letter of the desired command. For example,
- Alt
- Alt-C is the Center command, which causes EDIT to center the current
- Alt
- line between the left and right margins.
-
- Note that it is also possible to use the cursor control keys as a
- numeric pad, for ease of entering numbers, "+", and "-". To do so,
- the user should press the Num Lock key. After this key is pressed,
- Num Lock
- these keys will act as a numeric pad until Num Lock is pressed again.
- Num Lock
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- 2.5. Command Repetition
- 2.5. Command Repetition
-
- Several of the commands accept an optional repetition count that
- indicates the number of times the command should be executed. The
- repetion count is entered by pressing Esc, followed by a positive
- Esc
- number, and then typing the command key. For example, to move the
- cursor down ten lines, the user may type the following:
-
- Esc 10 Down
- Esc Down
-
- There is a default value for the repetition count that is used if the
- user simply types Esc followed by the command. The initial value for
- Esc
- this default is 5. The default value may be changed by typing Esc,
- Esc
- then the new value, and then Enter. The maximum repetition count is
- Enter
- 9999. The count may not be negative.
-
- The commands that accept a repetition count include the following:
-
- - basic cursor movement commands
- - find commands
- - replace commands
- - get command
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- The deletion commands do not accept a repetition count.
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- EDIT Users Manual
- Command Overview 2-6
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- 2.6. Input to Command Prompts
- 2.6. Input to Command Prompts
-
- A few EDIT commands require the user to enter a text string - a file
- name, a string to search for, etc. Other commands require the user
- to type a single character to select a particular option from a menu
- of subcommands. In both of these cases, the cursor is moved out of
- the main text area, and down to the prompt line. To help the user
- remember the position of the cursor in the file while the cursor is
- actually down on the prompt line, the character at that position is
- marked in reverse video.
-
- For commands that require the user to enter a string of text, the
- user should type each character in the string, and then press Enter
- Enter
- to terminate the string and execute the command. The Backspace key
- Backspace
- may be used to delete the last character of the string.
- Shift-Backspace will delete the entire string. To abort the command
- Shift Backspace
- requesting the string input, the user may type Esc. Note that the
- Esc
- Enter key is the large key just above the key labeled "PrtSc" near
- Enter
- the right side of the keyboard. The Backspace key is the large key
- Backspace
- just to the left of the key labeled "Num Lock" near the right side of
- the keyboard, just above the Enter key.
- Enter
-
- When a command requires the user to type a single character to select
- from a menu of subcommands, the subcommands are listed in parentheses
- on the prompt line, and the cursor appears at the right end of the
- list. The user selects the desired option by typing its first
- character. Typing any other character aborts the command.
-
- The user need not explicitly abort a command that requires string
- input or option selection in order to execute a command on one of the
- cursor control keys on the right side of the keyboard, the function
- keys on the left side of the keyboard, or one of the Shift commands.
- Shift
- Typing one these commands automatically aborts the current command
- and executes the new command.
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- EDIT Users Manual
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