Single Movements

The keys h, j, k, and l, right under your fingertips, move the cursor:

h

Left, one space

j

Down, one line

k

Up, one line

l

Right, one space

You can also use the cursor arrow keys (←, ↓, ↑, →), + and - to go up and down, CTRL-P and CTRL-N to also go up and down, or the ENTER and BACKSPACE keys, but they are out of the way.

At first, it may seem awkward to use letter keys instead of arrows for cursor movement. After a short while, though, you’ll find it is one of the things you’ll like best about vi—you can move around without ever taking your fingers off the center of the keyboard.

Before you move the cursor, press ESC to make sure that you are in command mode. Use h, j, k, and l to move forward or backward in the file from the current cursor position. When you have gone as far as possible in one direction, you hear a beep and the cursor stops. For example, once you’re at the beginning or end of a line, you cannot use h or l to wrap around to the previous or next line; you have to use j or k.² Similarly, you cannot move the cursor past a tilde (~) representing a line without text, nor can you move the cursor above the first line of text.

Numeric Arguments

You can precede movement commands with numbers. Figure 2-2 shows how the command 4l moves the cursor four character positions to the right, just as if you had typed l four times (llll).

Figure 2-2. Multiplying commands by numbers

The ability to multiply commands gives you more options and power for each command you learn. Keep this in mind as we introduce additional commands.

Movement Within a Line

When you saved the file practice, vi displayed a message telling you how many lines are in that file. A line is not necessarily the same length as the visible line (often limited to 80 characters) that appears on the screen. A line is any text entered between newlines. (A newline character is inserted into the file when you press the ENTER key in insert mode.) If you type 200 characters before pressing ENTER, vi regards all 200 characters as a single line (even though those 200 characters visibly take up several lines on the screen).

As we mentioned in Chapter 1, The vi Text Editor, vi has an option that allows you to set a distance from the right margin at which vi automatically inserts a newline character. This option is wrapmargin (its abbreviation is wm). You can set a wrapmargin at 10 characters:

:set wm=10

This command doesn’t affect lines that you’ve already typed. We’ll talk more about setting options in Chapter 7. (This one really couldn’t wait!)

If you do not use vi’s automatic wrapmargin option, you should break lines with carriage returns to keep the lines of manageable length.

Two useful commands that involve movement within a line are:

0 (digit zero)

Move to beginning of line.

$

Move to end of line.

In the following example, line numbers are displayed. (Line numbers can be displayed in vi by using the number option, which is enabled by typing :set nu in command mode. This operation is described in Chapter 7.)

1  With a screen editor you can scroll the page,
2  move the cursor, delete lines, insert characters,
   and more, while seeing the results of your edits
   as you make them.
3  Screen editors are very popular.

The number of logical lines (3) does not correspond to the number of visible lines (5) that you see on the screen. If the cursor were positioned on the d in the word delete, and you entered $, the cursor would move to the period following the word them. If you entered 0, the cursor would move back to the letter m in the word move, at the beginning of line two.

Movement by Text Blocks

You can also move the cursor by blocks of text: words, sentences, paragraphs, etc.

w

Move forward one word (alphanumeric characters make up words)

W

Move forward one Word (white space separates words)

b

Move backward one word (alphanumeric characters make up words)

B

Move backward one Word (white space separates words)

G

Go to a specific line

The w command moves the cursor forward one word at a time, counting symbols and punctuation as equivalent to words. The following line shows cursor movement by w:

cursor, delete lines, insert characters,

You can also move by word, not counting symbols and punctuation, using the W command. (You can think of this as a “large” or “capital” Word.)

Cursor movement using W looks like this:

cursor, delete lines, insert characters,

To move backward by word, use the b command. Capital B allows you to move backward by word, not counting punctuation.

As mentioned previously, movement commands take numeric arguments; so, with either the w or b commands you can multiply the movement with numbers. 2w moves forward two words; 5B moves back five words, not counting punctuation.

To move to a specific line, you can use the G command. Plain G goes to the end of the file, 1G goes to the top of the file, and 42G goes to line 42. This is described in more detail later in the section “The G (Go To) Command.”

We discuss movement by sentences and by paragraphs in Chapter 3. For now, practice using the cursor movement commands that you know, combining them with numeric multipliers.

Inserting New Text

You have already seen the insert command (i) used to enter text into a new file. You also use the insert command while editing existing text to add missing characters, words, and sentences. In the file practice, suppose you have the sentence:

you can scroll
the page, move the cursor, delete
lines, and insert characters.

with the cursor positioned as shown. To insert With a screen editor at the beginning of the sentence, enter the following:

Appending Text

You can append text at any place in your file with the append command, a. This works in almost the same way as i, except that text is inserted after the cursor rather than before the cursor. You may have noticed that when you press i to enter insert mode, the cursor doesn’t move until after you enter some text. By contrast, when you press a to enter insert mode, the cursor moves one space to the right. When you enter text, it appears after the original cursor position.

Changing Text

You can replace any text in your file with the change command, c. To tell c how much text to change, you combine c with a movement command. In this way, a movement command serves as a text object for the c command to affect. For example, c can be used to change text from the cursor:

cw

To the end of a word

c2b

Back two words

c$

To the end of the line

c0

To the beginning of the line

After issuing a change command, you can replace the identified text with any amount of new text, with no characters at all, with one word, or with hundreds of lines. c, like i and a, leaves you in insert mode until you press the ESC key.

When the change affects only the current line, vi marks the end of the text to be changed with a $, so that you can see what part of the line is affected. (See the example for cw, next.)

With an editor you can scroll the page,

Pith a screen editor you can scroll the page,

Changing Case

Changing the case of a letter is a special form of replacement. The tilde (~) command changes a lowercase letter to uppercase or an uppercase letter to lowercase. Position the cursor on the letter whose case you want to change, and type a ~. The case of the letter changes, and the cursor moves to the next character.

In older versions of vi, you cannot specify a numeric prefix or text object for the ~ to affect. Modern versions do allow a numeric prefix.

If you want to change the case of more than one line at a time, you must filter the text through a Unix command such as tr, as described in Chapter 7.

Deleting Text

You can also delete any text in your file with the delete command, d. Like the change command, the delete command requires a text object (the amount of text to be operated on). You can delete by word (dw), by line (dd and D), or by other movement commands that you will learn later.

With all deletions, you move to where you want the edit to take place, then give the delete command (d) and the text object, such as w for word.

Screen editors are are very popular,
since they allowed you to make
changes as you read through a file.

since they allowed you to make

Screen editors are very popular,
since they allow you to make
changes as you read through a file.

Screen editors are very popular,
since they allow you to make
changes as you read through a file.

zYou can move text by deleting text and then

Moving Text

In vi, you move text by deleting it and then placing that deleted text elsewhere in the file, like a “cut and paste.” Each time you delete a text block, that deletion is temporarily saved in a special buffer. Move to another position in your file and use the put command (p) to place that text in the new position. You can move any block of text, although moving is more useful with lines than with words.

The put command (p) puts the text that is in the buffer after the cursor position. The uppercase version of the command, P, puts the text before the cursor. If you delete one or more lines, p puts the deleted text on a new line(s) below the cursor. If you delete less than an entire line, p puts the deleted text into the current line, after the cursor.

Suppose in your file practice you have the text:

You can move text by deleting it and then,
like a "cut and paste,"
placing the deleted text elsewhere in the file.
each time you delete a text block.

and you want to move the second line, like a “cut and paste,” below the third line. Using delete, you can make this edit:

Copying Text

Often you can save editing time (and keystrokes) by copying a part of your file to use in other places. With the two commands y (for yank) and p (for put), you can copy any amount of text and put that copied text in another place in the file. A yank command copies the selected text into a special buffer, where it is held until another yank (or deletion) occurs. You can then place this copy elsewhere in the file with the put command.

As with change and delete, the yank command can be combined with any movement command (yw, y$, 4yy). Yank is most frequently used with a line (or more) of text, because to yank and put a word usually takes longer than simply to insert the word.

The shortcut yy operates on an entire line, just as dd and cc do. But the shortcut Y, for some reason, does not operate the way D and C do. Instead of yanking from the current position to the end of the line, Y yanks the whole line; that is, Y does the same thing as yy.

Suppose you have in your file practice the text:

With a screen editor you can
scroll the page.
move the cursor.
delete lines.

You want to make three complete sentences, beginning each with With a screen editor you can. Instead of moving through the file, making this edit over and over, you can use a yank and put to copy the text to be added.

Yanking uses the same buffer as deleting. Each new deletion or yank replaces the previous contents of the yank buffer. As we’ll see in Chapter 4, up to nine previous yanks or deletions can be recalled with put commands. You can also yank or delete directly into up to 26 named buffers, which allows you to juggle multiple text blocks at once.

Repeating or Undoing Your Last Command

Each edit command that you give is stored in a temporary buffer until you give the next command. For example, if you insert the after a word in your file, the command used to insert the text, along with the text that you entered, is temporarily saved.

With a screen editor you can
scroll the page.
With a screen editor you can
move the cursor.

Numeric Arguments for Insert Commands

Except for o and O, the insert commands just listed (plus i and a) take numeric prefixes. With numeric prefixes, you might use the commands i, I, a, and A to insert a row of underlines or alternating characters. For example, typing 50i* ESC inserts 50 asterisks, and typing 25a*- ESC appends 50 characters (25 pairs of asterisk and hyphen). It’s better to repeat only a small string of characters.

With a numeric prefix, r replaces that number of characters with a repeated instance of a single character. For example, in C or C++ code, to change || to &&, you would place the cursor on the first pipe character and type 2r&.

You can use a numeric prefix with S to substitute several lines. It’s quicker and more flexible, though, to use c with a movement command.

A good case for using the s command with a numeric prefix is when you want to change a few characters in the middle of a word. Typing r wouldn’t be correct, and typing cw would change too much text. Using s with a numeric prefix is about the same as typing R.

There are other combinations of commands that work naturally together. For example, ea is useful for appending new text to the end of a word. It helps to train yourself to recognize such useful combinations so that they become automatic.

Problems with vi Commands

• When you type commands, text jumps around on the screen and nothing works the way it’s supposed to.

  Make sure you’re not typing the J command when you mean j.

  You may have hit the CAPS LOCK key without noticing it. vi is case-sensitive; that is, uppercase commands (I, A, J, etc.) are different from lowercase commands (i, a, j), and if you hit this key, all your commands are interpreted not as lowercase but as uppercase commands. Press the CAPS LOCK key again to return to lowercase, press ESC to ensure that you are in command mode, and then type either U to restore the last line changed or u to undo the last command. You’ll probably also have to do some additional editing to fully restore the garbled part of your file.