Visual ( vi ) Editor

1. 7 CHAPTER Visual (vi) Editor • Objectives • Upon completion of this module, you should be able to: • Define the three modes of operation used by the vi editor. • Start the vi editor. • Position and move the cursor in the vi editor. • Switch between vi modes. • Create and delete text. • Copy or move text. • Set vi options. • Perform search and replace functions within the vi editor. • Exit the vi editor.

2. Introducing vi • The visual display (vi) editor is an interactive editor used to create or modify text files. • All text editing with the vi editor takes place in a buffer. • Changes can either be written to the disk or be discard. • For those who intend on becoming system administrators, it is important to know how to use the vi editor. • You need to know how to use the vi editor in case the windowing system is now available. • The vi editor is also the only text editor that can be used to edit certain system files without changing the file’s permissions. Figure 7-1 Terminal Window – Initial vi Display

3. vi Modes • The vi editor is a command-line editor that has three basic modes of operation: • Command mode • Edit mode • Last line mode

4. Command Mode • This is the default mode for the vi editor. • In this mode, you can enter commands to delete, change, copy, and move text; position the cursor; search for text strings; or exit the vi editor.

5. Edit Mode • In this mode, you can enter text into a file. • To instruct the vi editor to enter edit mode, enter one of the following three commands: • i (insert) • o (open) • a (append)

6. Last Line Mode • While in command mode, you can use advanced editing commands by typing a colon (:), which places you at the bottom line of the screen. • This is called last line mode. • However, all commands are initiated from command mode.

7. Switching Modes • By typing i, o, or a command, the vi editor leaves the default command mode and enters edit mode. • In edit mode, text is not interpreted as commands by the vi editor. Now, everything you type is entered into the file as text. • When you have finished entering text in the file, you can return the vi editor to command mode by pressing the Escape key. • When you are back in command mode, you can then save the file an quit the vi editor. • For example: • Type vifinename to create a file. • Type the i command to insert text. • Press the Escape key to return to command mode. • Type :wq to write and save the file and exit thevi editor.

8. Invoking the vi Editor • To create a new file, invoke the vi editor with a new file name by typing commands to create, edit, or view a file. • Command Format • vi option(s) filename • view filename • Input commands • To insert or append text, use the commands in Table 7-1. Table 7-1 Note The vi editor is case sensitive, so use the specified case when using these cursor-input commands.

9. Table 7-2 Command Meaning h, , or Back Space Moves left one character j or Moves down one line k or Moves up one line l, , or Space bar Moves right ( forward ) one character w Moves forward one word b Moves back one word e Moves to the end of the current word $ Moves to the end of the line 0 (zero) Moves to the beginning of the line ^ Moves to the first non-whitespace character on the line Return Moves down to the beginning of the next line Control-F Pages forward one screen Control-D Scrolls down one-half screen Control-B Pages back one screen Control-U Scrolls up one-half screen Control-L Refreshes the screen Positioning Commands • Table 7-2 shows the key sequences that control cursor movement in the vi editor.

10. Editing Commands • Deleting Text • To delete text, use the options in table 7-3. Table 7-3

11. Undoing, Repeating, and Changing Text Commands • To change text, undo a change, or repeat an edit function, use the commands in Table 7-4. • Many of these commands change the vi editor to edit mode. • To return to command mode, press the Escape key.

12. Edit Commands for the vi Editor -1 Table 7-4

13. Edit Commands for the vi Editor -2 Table 7-4 ( Continued )

14. Edit Commands for the vi Editor -3 • To search and replace text, use the options in table 7-5. Table 7-5

15. Copying and Pasting Text • The copy commands write the copied text into a temporary buffer. The paste commands read the text from the temporary buffer and write the text into the current document at the specified location. • To copy and paste text, use the options in table 7-6 Table 7-6 Note Both delete and yank write to a buffer. When yanking, deleting, and pasting, the put commands insert the text differently depending on whether you are pasting words or lines.

16. Saving and Quitting Files Table 7-7

17. Customizing Your vi Session • The vi editor includes options for customizing edit sessions, such as: • Displaying line numbers • Displaying invisible characters, such as tab and end-of-line characters • Use the set command in command mode to control these options, as shown in table 7-8. • You can also place these options in a file you create in you home directory called .exrc. • The set options are placed in this file, without the preceding colon, one command to a line. • After the .exrc file has been created, it is read by the system each time you open a vi session.

18. Edit Session Customization Commands Table 7-8

19. Positioning & Refreshing Command • To find a particular line, use the options in table 7-9. Table 7-9 • To clear the screen or insert files, use the option in table 7-10. Table 7-10

20. $ vi demo Command Mode : / ? i a o Return Escape Last Line Mode Edit Mode Chapter7 exercise: Using the vi Editor • Tasks • Complete the following steps: • In your home directory, there should be a file called tutor.vi. Make sure you are currently in your home directory, and then open this file with the command: This opens a vi tutorial file. • Complete the lessons outlined in this tutorial. $ vi tutor.vi