A A Beginner's Guide to Using vi

Whether you are writing memos or modifying C programs, editing text files is one of the most common uses of any computer system. The vi text editor (hereafter known as vi) is particularly well-suited for the day-to-day text editing tasks of most computer users. You can quickly and easily open a file, edit it, and save the results using vi.

The vi text editor is a full-featured text editor with the following major features:

Fast processing, especially on startup and global operations
Full screen editing and scrolling capability
Separate text entry and edit modes
Global substitution and complex editing commands using the underlying ex commands
Access to operating system level commands
Ability to customize system parameters and keyboard mappings

This appendix shows you how to use the basic features of vi. After completing the exercises in this appendix, you will be able to:

Create and save a new file
Access (open) an existing file
Move the cursor within the file
Enter new text
Change existing text
Search for strings
Move and copy text
Make global substitutions
Write all or part of the text to a file
Delete, move, or copy blocks of text
Customize your editing environment

This appendix only provides an introduction to the features of vi If you want to learn more, see the vi(1) reference page. You may also read one of the many books on the market that describe vi's advanced features.

This appendix is divided into three sections. The first section gets you started with vi. The second section shows you some advanced techniques for speeding up your work. The third section shows you how to take advantage of the power of the underlying ex commands.

A.1 Getting Started

This section shows you how to create a file with vi, save the file, move the cursor around in the file, add text, delete text, and modify text.

A.1.1 Creating a File

To create the file, my.file, that will be used in the examples throughout this appendix, enter the vi command as shown below:

$ vi my.file [Return]

Your screen will look like this:

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"my.file" [New file]

The lines beginning with tildes (~) represent the blank lines in the file. Because my.file is empty, all lines in the file begin with a tilde (~).

The vi editor has two modes: command mode and input mode. Command mode is the mode vi is in when it is started. In command mode, the characters you enter are interpreted as commands for manipulating the text. When vi is in input mode, the characters you enter are interpreted as text.

When you create a new file with the vi command, the vi editor is in the command mode. That is, vi is waiting for you to enter a command. However, at this point you want vi to be in the input mode so you can insert text into my.file, which is empty.

Put vi into the input mode by typing:

The i command will not be displayed on the screen. The vi editor is now in the input mode and vi will interpret all characters that you type to be text.

In the sample text below, notice the use of the Escape key on the last line of input and the use of the :wq command to save the file and exit the vi editor. Type the sample text exactly as shown. If you make a mistake, use the Backspace key to correct it; press the Return key where indicated to move to the next line of text:

You can use this text file [Return] to experiment with vi. [Return] The examples shown here [Return] will teach you the basics of vi. [Escape] ~ ~ ~ ~ ~ :wq

 "my.file" 4 lines, 108 characters

Note
Depending upon how your terminal or workstation is set up, the Escape key may be programmed to perform a different function. It is possible that one of the function keys on your keyboard (possibly F11) may have been set up to perform the escape function. See your system administrator if your Escape key does not operate properly.

Pressing the Escape key while vi is in the input mode puts vi back into the command mode; once in the command mode vi interprets anything you type to be a command. The :wq command writes (saves) the file with the name my.file into your current directory and quits the vi editor.

The format of the :wq command is much different than other vi commands because :wq is not a vi command; it is an ex command. When you press a colon ( :) when vi is in the command mode, notice that it appears at the bottom of the screen. The colon ( :) begins all ex commands from within vi. All ex commands are executed when vi is in the command mode. You must press the Return key after the command to signify to ex that you are finished entering the command. See Section A.3 to learn more about ex commands.

If you lose track of which mode vi is in, press the Escape key a few times to make sure vi is in the command mode. If your system is so configured, you will hear a bell when you press the Escape key that signals that vi is indeed in the command mode.

The Escape key and its use in vi and exiting vi using several different methods are described in more detail later in this appendix.

The text you just entered in my.file will be used in the remaining examples in this appendix.

A.1.2 Opening an Existing File

Whether you are creating a new file or opening an existing file, the syntax for using vi is the same:

vi filename

To open the my.file file, enter the vi command as follows:

$ vi my.file

Your screen should look like this:

You can use this text file
to experiment with vi.
The examples shown here
will teach you the basics of vi.

 

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~
"my.file" 4 lines, 108 characters

The text you entered in the file will be displayed at the top of the screen. The lines beginning with tildes (~) represent the blank lines in your file. The text at the bottom of the screen shows the name of the file, the number of lines in the file, and the number of characters in the file.

A.1.3 Saving a File and Quitting vi

In the previous example, you learned that the :wq command saved the file and quit the vi editor. However, there are several other options available to save and quit a file:

Save a file and continue working in it
Save the file and quit (exit) vi
Quit vi without saving the changes made to the file

If you are working on a large text file and have been adding, changing, and deleting a lot of information, it is suggested to save the file often (perhaps every 10 minutes) to protect against potential data loss. The write command is used to save an entire file to the current directory. The format of the write command is:

:w filename

The entry of filename is optional and is used only when you want to save a file under a different filename. Omitting filename from the command automatically saves a file to it's current file name. When you enter the :w command, the current file name, number of lines, and number of characters is displayed at the bottom of your screen. If you entered a new file name, the new file name will be displayed.

Note
If you specify a new file name with the :w command, you will have two files saved in your directory: the new file name you just entered and the original file name.

If you are finished making changes to a file, you can save the file and quit vi at the same time. The format of the write and quit command is:

:wq

The :wq command saves a file to the same file name, quits vi, and brings you back to your shell prompt.

You also have the option to quit a file and vi simultaneously without saving the changes you may have made. This option is useful if, for example, you have deleted many lines of information by mistake and you want to start all over again. Quitting vi will restore your file to its original state. However, quitting vi to restore a file to its original state will only work if you have not saved the file previously during the current editing session. To quit your file and vi without saving your changes enter:

:q!

Quitting a file with the :q! command will not delete the file from your directory. Your file will still reside in the directory, but it will not contain any of the changes you may have made.

Table A-1 summarizes the commands used to save files and quit the vi editor.

Table A-1: Write and Quit Command Summary

Command	Result
`:w`	Saves the entire file to the current file name; does not exit the `vi` editor.
`:w filename`	Saves the entire file to the new file name; does not exit the `vi` editor. The new file name and original file name reside in the directory.
`:wq`	Saves the entire file to the current file name and exits the `vi` editor simultaneously.
`:q!`	Quits the file; exits the `vi` editor; does not save any changes made to the file since the last time the file was saved.

A.1.4 Moving Within a File

If you have closed my.file, reopen it by using the command:

$ vi my.file

The cursor should be on the first character in the file: the Y in the word You.

As mentioned previously in this appendix, vi is in command mode at start up. In command mode, the characters you enter are treated as commands rather than as text input to the file.

A.1.4.1 Moving the Cursor Up, Down, Left, and Right

Certain keys on the keyboard have been designated to be movement keys when vi is in the command mode. The following letters on the keyboard control cursor movement:

h (move the cursor one character to the right)
j (move the cursor down one line staying in the same position)
k (move the cursor up one line staying in the same position)
l (move the cursor one character to the left)

Using the movement keys, move the cursor to the first letter of the word experiment by typing:

lllj

If your keyboard is equipped with arrow keys, you may be able to use the arrow keys to move left, right, up, or down as well. However, using the h, j, k, and l keys allows you to keep your fingers on the main section of the keyboard for faster typing. On some keyboards, the h, j, k, and l keys are repetitive keys. That is, holding the key down will repeat the key action until you release the key. For instance, holding down the j key will rapidly scroll through the lines in a file.

In the command mode, the Return key acts as a cursor movement key. Pressing the Return key moves the cursor to the first character of the next line. This movement differs from the j movement key because the Return key positions the cursor at the first character of the next line whereas the j moves the cursor to the same character position on the next line.

In the command mode, the hyphen (-) moves the cursor to the first character of the previous line. This feature is useful to move backward through files. This movement differs from the k movement key because the hyphen (-) positions the cursor at the first character of the previous line whereas the k moves the cursor to the same character position on the previous line.

If you tested any of the cursor movement keys described above, make sure your cursor is positioned at the first letter of the word experiment before continuing to the next section.

A.1.4.2 Moving the Cursor by Word, Line, Sentence, and Paragraph

You can use the w command to move the cursor by whole word boundaries. The w command moves the cursor forward to the beginning of the next word. Move the cursor to the beginning of the word with by typing:

w

You can use the b command to move backward to the beginning of the previous word. For example, move to the beginning of the word experiment by typing:

b

Now see what happens when you do not use the b command from the beginning of a word by typing:

llllb

The cursor returns to the beginning of the word experiment.

The word motion commands will wrap to the next or previous text line when appropriate. Move the cursor to the beginning of the word text by typing:

bbb

Notice how the cursor moved backward and wrapped around to the previous line.

There are a few other interesting movement commands you should know about. The zero (0) moves the cursor to the beginning of the current line, and the dollar sign, ($) moves the cursor to the end of the current line.

The close parenthesis [)] moves the cursor to the beginning of the next sentence, and the open parenthesis [(] moves the cursor to the beginning of the previous sentence.

The right brace (}) moves the cursor to the beginning of the next paragraph, and the left brace ({) moves the cursor to the beginning of the previous paragraph.

A.1.4.3 Moving and Scrolling the Cursor Forward and Backward Through a File

In larger files, you can move the cursor by whole screenfuls by pressing certain control keys:

Ctrl/F moves the cursor one full screen forward
Ctrl/B moves the cursor one full screen backward
Ctrl/D moves the cursor and scrolls down (forward) a half screen
Ctrl/U moves the cursor and scrolls up (backward) a half screen

The following uppercase letters also designate cursor movement over large boundaries of text:

The H command moves the cursor Home; that is, to the first character in the file
The G command instructs the cursor to Go to the last line in the file

A.1.4.4 Movement Command Summary

The vi text editor has many more cursor movement commands. When you have learned the basics documented in this appendix, refer to the vi(1) reference page for more information.

Table A-2 summarizes the cursor movement commands. The cursor movement keys are in effect only when vi is in the command mode.

Table A-2: Cursor Movement Command Summary

Command	Result
`h`	Move the cursor one character to the right.
`j`	Move the cursor down one line in the same position.
`k`	Move the cursor up one line in the same position.
`l`	Move the cursor one character to the left.
`Return key`	Move the cursor to the beginning of the next line.
`-`	Move the cursor to the beginning of the previous line.
`w`	Move the cursor forward to the beginning of the next word.
`b`	Move the cursor backward to the beginning of the previous word.
`0`	Move the cursor to the beginning of the current line.
`$`	Move the cursor to the end of the current line.
`)`	Move the cursor to the beginning of the next sentence.
`(`	Move the cursor to the beginning of the previous sentence.
`}`	Move the cursor to the beginning of the next paragraph.
`{`	Move the cursor to the beginning of the previous paragraph.
`Ctrl/D`	Scroll down (forward) a half screen.
`Ctrl/F`	Move the cursor forward one screen.
`Ctrl/B`	Move the cursor backward one screen.
`Ctrl/U`	Scroll up (backward) a half screen.
`H`	Move the cursor home (to the first character in the file).
`G`	Move the cursor to the last line of the file.

A.1.5 Entering New Text

To enter new text into a file, vi must be in the input mode. In input mode, the characters you enter are inserted as text directly into the file. Remember that when vi is in the input mode, you can return vi to the command mode by pressing the Escape key once.

There are several different commands used to insert text, and all of the commands that are used to insert text automatically place vi in the input mode as soon as the command is typed.

To begin this exercise, open my.file and make sure the cursor is positioned at the word text in the first line of the file.

As you did initially to insert text into my.file, you will use the insert command to insert the word new just before the word text. With the cursor positioned on the first t in the word text, put vi into the input mode command by typing the insert command:

i

Next, enter the word new and press the space bar once:

new [Space]

Exit the input mode by pressing the Escape key:

[Escape]

The cursor should now be positioned on the space between the words new and text.

The i command starts inserting text at the character just before the cursor. That's why you have to remember to press the Space bar to insert a space between words if the cursor was positioned at the first character in a word when you started to insert text.

Another command that is used to insert text is the append ( a) command. In contrast to the insert command, the a command adds (or appends) the characters you type just after the cursor position. To see how the a command works, use the cursor movement keys to move to the letter u in the word You, and type:

a , too, [Escape]

The vi text editor appended the text you typed to the end of the word You. The cursor should now be positioned on the second comma. The o command opens a new line below the line with the cursor and allows you to insert text at the start of that new line. To add a sentence to the end of this file, move the cursor to the last line of the file by pressing the Return key three times:

[Return] [Return] [Return]

The cursor should be positioned at the word will. To open a new line below the current line and automatically put vi into the input mode, type:

o

Enter the sample text shown below (including pressing the Return key where indicated), and press the Escape key to return to command mode when you are finished.

New text can be easily entered [Return] while in input mode. [Escape]

Your screen should now look like this:

You, too, can use this new text file
to experiment with vi.
The examples shown here
will teach you the basics of vi.
New text can be easily entered
while in input mode.
~
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The O command opens a new line above the current line and starts inserting text at the start of the new line. This command is most useful for adding new text to the top of an existing file, but can be used anywhere in a file. To practice using this command to open a line and insert text, move the cursor to the first line in the file (using the cursor movement command H perhaps) and type:

O Opening a new line is easy. [Escape]

The vi text editor is back in the command mode once the Escape key is pressed.

There are two other commands that put vi in the input mode: the I and A commands. The I command inserts text at the beginning of the current line. The A command appends text after the last character at the end of the current line.

Practice inserting text to the beginning of a line, by typing:

I Inserting text is easy. [Space] [Escape]

Practice appending text to the end of a line by typing:

A Really! [Escape]

Your screen should now look like this:

Inserting a line is easy. Opening a new line is easy. Really!
You, too, can use this new text file
to experiment with vi.
The examples shown here
will teach you the basics of vi.
New text can be easily entered
while in input mode.
~
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Table A-3 summarizes the commands used to insert and append text to a file. These commands are executed from the command mode and automatically put vi into the input mode.

Table A-3: Text Insertion Command Summary

Command	Result
`i`	Inserts text immediately before the current cursor position.
`a`	Appends text immediately after the current cursor position.
`I`	Inserts text at the beginning of the current line.
`A`	Appends text to the end of the current line.
`o`	Opens a new line directly below the current line.
`O`	Opens a new line directly above the current line.

A.1.6 Editing Text

Up to this point you have only learned how to add new text to the file, but what if you need to change some text? The vi text editor provides commands for deleting and changing text. For example, to remove the word easily, from the sixth line in my.file, move the cursor to the first character of the word and enter:

dw

This command is a combination of the delete command d, and the motion command w. In fact, many vi commands can be combined with motion commands to specify the duration of the action. The general form of a vi command follows:

[ number ] [ command ] motion

The command entry represents an action command, motion represents a motion command, and number optionally represents the number of times to perform the command. You also can use this general form to move the cursor in larger steps.

To illustrate this concept, move the cursor to the beginning of my.file by typing H. Now, to move the cursor forward four words, enter:

4w

The cursor has moved four entire words and is positioned at the first letter of the fifth word, easy.

A.1.6.1 Deleting Words

Using the general form of commands, you can delete the last five words of this text file. Move the cursor to the beginning of the last line by pressing the Return key several times and enter:

5dw :w

It takes five words to delete the whole line rather than four because the period at the end of the line counts as a word. All punctuation counts as one word when you're using the delete word command. As a reminder that you should save a file often, this example also had you write the file (save it) using the :w command.

Suppose you only want to delete a portion of a word? The x command deletes one character at a time. To see how this command works, move the cursor to the letter s in the word examples. Press the x key once to delete the letter s.

A.1.6.2 Deleting Lines

The dd command is a shortcut for deleting whole lines at a time. The dd command can be used with a number to delete multiple lines as well. For example, position the cursor at the sixth line in the file (at the line beginning with the word New) and type:

2dd

The sixth and seventh lines (even though the seventh line is empty) of the file are deleted simultaneously. The dd command can be used without specifying a number to delete one line at a time.

The D command clears the current line of text from the current cursor position to the end of the line but does not delete the line itself. If the cursor is positioned at the beginning of the line, the entire line is cleared. This command speeds up your work because you don't have to know how many words are in the line to be able to delete them (as you would, for example, if you were using the dw command). This command is useful if you want to rewrite an entire line. With the cursor positioned at the beginning of the line, the D command followed by one of the text insertion commands ( i, I, a, or A) allows you to clear the current line of text and reenter new text with a minimum of keystrokes.

A.1.6.3 Changing Text

The command for changing text, c, can be used to combine the actions of deleting and returning to input mode. It follows the same general form as the d command. To change the text new text to almost new demo, move the cursor to the first character in the word "new", and enter the command:

2cw

The text will not immediately disappear. Instead, a dollar sign ($) is placed at the end of the change range (the last t in text), and vi is placed in input mode automatically. The text you enter will overwrite the existing text up to the dollar sign and then extend the text range as needed. Enter the new text by typing:

almost new demo [Escape]

A.1.6.4 Text Editing Command Summary

As shown in the previous sections, the text editing commands can be used together with the motion commands to give you more editing power. The text editing commands can be combined with a number to change or delete large blocks of words or lines simultaneously. Table A-4 summarizes the commands used to edit text.

Table A-4: Text Editing Command Summary

Command	Result
`cw`	Changes the current word to the new text you type. You may change the word with as much next text as necessary. The Escape key signals the end of the change.
`ncw`	Changes `n` number of words to the new text you type. The new text is not limited to just `n` words. You may change `n` words with as much new text as necessary. The Escape key signals the end of the change.
`D`	Clears the text from the current cursor position to the end of the line. Does not delete the space used by the line thereby allowing you to add more text.
`dd`	Deletes the current line.
`ndd`	Deletes `n` number of lines beginning with the current line.
`dw`	Deletes the current word.
`ndw`	Deletes `n` number of words beginning with the current word.
`x`	Deletes the current character.

A.1.7 Undoing a Command

If you make a change and then realize it was in error, you may still be able to correct it if you haven't executed another command. The u command undoes the last command entered. Undo the last command, 2cw, by typing:

u

The text string almost new demo will be changed back to new text if you didn't execute any other commands since you executed the 2cw command.

The uppercase U command undoes all changes to the current line and restores the line to it's original state. The U command works only if you have not moved the cursor to another line.

A.1.8 Finishing Your Edit Session

After you finish the exercises in this appendix, you should save the file and quit vi. To save your changes and quit vi, enter:

:wq [Return]

If you want to quit vi without saving your changes, you can do so by entering:

:q! [Return]

You have now learned enough about vi to edit any file. The following sections show you some advanced techniques that can improve your productivity and allow you to customize your environment.

A.2 Using Advanced Techniques

This section shows you how to search for text strings, move text, and copy and paste text. As you work with larger documents, all these tasks increase your ability to work efficiently.

A.2.1 Searching for Strings

In a large document, searching for a particular text string can be very time consuming. The slash ( / ) command prompts for a text string to search for in the file. When you enter the slash (/) and press the Return key, vi searches the file for the first occurrence of the text string you entered.

If you do not have it open, reopen the my.file file. Move to the top of the document using one of the cursor movement keys you learned earlier in this appendix. To search for the text string th, enter the following:

/th [Return]

As soon as you enter the slash (/) command, the slash (/) is displayed at the bottom of the screen (similar to the way in which the colon (:) works). When you entered the text string th, it was echoed (displayed) at the bottom of the screen. You can use the Backspace key to fix mistakes when you enter the search string.

After you press the Return key, the cursor moves to the first occurrence of the string (the th in the word this). The n (next) command continues the search for the next occurrence of the last string you searched for. Try it now by entering:

n

The cursor should move to the next occurrence of the string, which is the th in the word with.

Similarly, the N command searches for the next occurrence of the search string, but it searches in the opposite direction of the n command. The N finds the previous occurence of the string.

The question mark ( ?) command is also used to initiate a search for text strings, but the question mark (?) initiates a backward search through the file. When you search backward, the n command moves the cursor backward to the previous occurrence of the string, and the N command moves the cursor forward (exactly the opposite of the way in which they work with a slash (/) search).

A.2.2 Deleting and Moving Text

To move a block of text, you must first select the text to move. You already know how to do this. The delete ( d) command not only deletes a line of text but also copies it to a paste buffer. Once in the paste buffer, the text can be moved (or pasted) by repositioning the cursor and then using the lowercase p command to paste the text on the line after the current cursor position.

Move the cursor to the first line in the file and type:

dd

The line is deleted and copied into the paste buffer, and the cursor is located on the next line in the file. To paste the line in the buffer back into the file, after the line on which the cursor is positioned, enter:

p

The uppercase letter P (Paste) command is used to paste text on the line above the cursor rather than below it.

If you delete a letter or block of words, the deleted text will be pasted into the new position within the current line. For example, to move the word can to just before the word with, use the following command sequence (remember to use an uppercase P):

/can [Return] dw /with [Return] P

A.2.3 Yanking and Moving Text

You copy text in the same manner as you move it, except that instead of using the delete text command d, you use the yank text command, y. The y command copies (or yanks) the specified text into the paste buffer without deleting it from the text. It follows the same syntax as the d command. You can also use the yy command to yank an entire text line into the paste buffer, in the same way as dd.

For example, to copy the first two lines of the file to a position immediately underneath them, enter the following command sequence from the first line of the file:

2yy j p

You must move the cursor down one line using j or the two lines will be pasted after the first line rather than after the second.

A.2.4 Other vi Features

You may want to try some of the other features of vi. The vi(1) reference page lists all of the available commands. You may want to pay particular attention to the following:

J: Joins the next line of text to the current line of text.

.: Repeats the last command.

s: Substitutes the current character with the following entered text.

x: Deletes the current character.

~: Changes the alphabetic case of the current character.

!: Executes an operating system command on the current line of text and replaces the text with the output.

Ctrl/L: Refreshes the screen when problems with the screen display occur. Any time your screen is displaying confusing output, press Ctrl/L.

A.3 Using the Underlying ex Commands

The vi text editor is based upon the ex line editor. The underlying ex line editor can bring the power of global changes to your entire text file or any large piece of it. You can access ex commands from within vi by using the colon ( :) command. You were introduced to ex commands earlier in this appendix with the :wq and :q! commands for writing and quitting an editing session.

The colon ( :) command causes ex to prompt for a command line at the bottom of the editor screen with a colon ( :). Each ex command is ended by pressing the Return key. You can also enter ex more permanently with the vi command Q. This command turns processing over to ex until you explicitly return to vi. This often happens accidentally. If it should happen to you, you can return to vi by typing vi at the colon ( :) prompt followed by the Return key as follows:

:vi [Return]

An ex command acts on a block of lines in your text file according to the following general syntax:

:[address[,address]]command

The command, along with any of its arguments, acts on the lines between and including the first and second address. If one address is specified, the command acts only on the specified line. If no address is specified, the command acts only on the current line. Addresses can be specified in a number of ways. Some of the more common address specifications are the following:

line number: Address by absolute line number.

/pattern/: Next line that contains the pattern.

.: Line that the cursor is on.

$: Last line of the file.

address±lines: Relative offset from the addressed line.

%: All the lines in the file, and is used once in place of both addresses.

The following sections show some of the most generally useful ex commands, and some of the customization features offered by ex. You should read the ex(1) reference page for a more detailed list of commands.

A.3.1 Making Substitutions

The most common substitution task, possibly the most common ex task, is a global substitution of one word or phrase for another. You can do this with the s command. If you have closed the my.file file, reopen it. To change every occurrence of "is" to "was", use the following command:

:%s/is/was/g [Return]

This substitution command is applied to all lines in the file by the % address. The slash (/) is used as a separator. The g argument at the end of the command causes the substitution to occur globally, that is, on each instance of the pattern within each line. Without the g argument, substitution occurs only once on each line.

You should be careful when making substitutions to ensure that you get what you want. In the previous command line, the word this has changed to thwas because every occurrence of is was changed to was.

You can add a c argument along with the g argument to prompt for confirmation before each substitution. The format of the confirmation is a bit complex; however, it is well worth using when you want to be scrupulous about making global changes.

As an example of confirming a substitution, change the word thwas back to this by issuing the following command:

:%s/thwas/this/gc [Return]

The following prompt appears at the bottom of the screen:

You, too, use thwas new text file
              ^^^^^

As shown in the next example, type y and press the Return key. You are then prompted for the second substitution:

You, too, use thwas new text file ^^^^^ y [Return] You, too, use thwas new text file ^^^^^

Type y and press the Return key, and in response to the Hit return to continue prompt, press the Return key once again as follows:

You, too, use thwas new text file ^^^^^ y You, too, use thwas new text file ^^^^^ y [Return] [Hit return to continue] [Return]

You will find that the two occurrences of the word thwas have been changed back to this. In addition, vi is back in the command mode with the cursor positioned at the first character of the line with the last substitution.

Now try another substitution on your example file. Add three lines of new text to the file by using the $ (go to beginning of last line), o (create new line), yy (yank), and p (paste) commands as follows:

:$ [Return] o Some new text with a mispelling. [Escape] yy p p p

You now should have four lines of new text, all containing the incorrectly spelled word mispelling.

To fix the spelling error, enter one of the following commands:

:1,$s/mispelling/misspelling/ [Return]

:5,8s/mispelling/misspelling/ [Return]

In the first example, the address 1,$ indicates that the substitution should begin on line one (1) and end at the last line of the file ($). In the second example, 5,8 indicates that the substitution should being on line five and end on line eight. You do not need to use the g operator in either case because the change is only necessary once on each line.

A.3.2 Writing a Whole File or Parts of a File

The :wq command is a special ex command that writes the whole file. It combines the features of the write command w and the quit command q. The only argument that the quit command can take is the exclamation point (!). It forces the session to quit even if changes made to the file would be lost by quitting.

The w command can also take addresses and a filename argument, which allows you to save part of your text to another file. For example, to save the first three lines of your text to the new file my.new.file, use the following command:

:1,3w my.new.file [Return] "my.new.file" [New file] 3 lines, 130 characters

A.3.3 Deleting a Block of Text

The delete command in ex is d, just as in vi. To delete from the current line to the end of the file, use the following command:

:.,$d [Return]

A.3.4 Customizing Your Environment

The ex editor provides two mechanisms for customizing your vi environment. You can use the :set command to set environment variables, and the :map command to map a key sequence to a vi command key.

Environment variables are set either by assigning them as option or no option for Boolean variables, or by assigning them as option=value. The full set of environment variables is described in the ex(1) reference page. Table A-5 lists some common variables.

Table A-5: Selected vi Environment Variables

Variable	Description
`errorbells`	Specifies that when an error is made, a bell sounds. This is the default setting.
`ignorecase`	Specifies that when performing searches, the case of characters should be ignored. The default variable setting is `noignorecase`.
`number`	Specifies that line numbers are to be displayed at the left margin. The default variable setting is `nonumber`.
`showmatch`	Specifies that when you enter a matching parenthesis or brace, the cursor moves to the matching character and then returns. The default variable setting is `noshowmatch`.
`tabstop`	Specifies the amount of space between tab stops. The default setting is 8.
`wrapscan`	Specifies that searches should wrap around the beginning or end of the file. This is the default variable setting.
`wrapmargin`	Creates an automatic right margin located a specified number of characters from the right side of your screen. Whenever your cursor reaches the specified right margin, an automatic new line is generated, and the word you are typing is brought to the next line. We recommend that you set the `wrapmargin` variable to a value with which you are comfortable. Otherwise, `vi` will use the default setting of 0. Using the default setting means that your cursor jumps to the next line when it reaches the end of your screen; however, parts of the word you are keying may be on separate lines.

To display the line numbers of your example file enter the following command:

:set number [Return]

To remove the line numbers, enter the following command:

:set nonumber [Return]

The :map command sets a single vi command key to a vi command sequence. The syntax for the :map command follows:

:map key sequence [Return]

This command sequence replaces any existing command for that key. The command sequence should be identical to the keystrokes you want to map, except that special keys such as the Return key, the Escape key, and keys modified with the Ctrl key must be quoted first with Ctrl/V. Because the q and v keys do not have commands associated with them, they are good keys to map.

For example, to map a key sequence that inserts a line into your text that says "This space held for new text", you could use the following command:

:map q oThis space held for new text [Ctrl/V] [Escape] [Return]

Note the use of Ctrl/V to quote the Escape character.

A.3.5 Saving Your Customizations

You can make your environment customizations permanent by placing the appropriate ex commands in a file named .exrc in your home directory. Commands in this file will take effect every time you enter vi or ex. In this file, you do not need to use the vi command :, because these commands are read directly by the underlying ex editor.

For example, to customize your environment to always display line numbers for your files, to use the map sequence shown in the previous section, and to set an automatic right margin of five spaces, you would first open the .exrc file with vi in your home directory, and add the following lines of text:

set number map q oThis space held for new text[Ctrl/V][Escape] set wrapmargin=5

After you write this file, verify that it works by opening your example file.