6.5 Basic vi Commands

The following sections explain several categories of vi commands. These include:

• Moving around in a file

• Inserting text

• Changing and substituting text

• Undoing changes to text

• Deleting text

• Copying and moving text

• Repeating commands

6.5.1 Moving Around in a File

In the previous sections you learned how to create, save, print, and exit a vi file. Now that you have created a file, you'll need to understand the concepts required to navigate within it. Open your practice file now, and try out each of the commands discussed in this section.

6.5.1.1 Moving the Cursor

When you start vi, the cursor is in the upper left corner of the vi screen. In command mode, you can move the cursor with a number of keyboard commands. Certain letter keys, the arrow keys, and the Return key, Back Space (or Delete) key, and the Space Bar can all be used to move the cursor when you're in command mode.

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Note -

Most vi commands are case-sensitive; the "same" command typed in lowercase and uppercase characters could have radically different effects.

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Moving with Arrow Keys

If your machine is equipped with arrow keys, try these now. You should be able to move the cursor freely about the screen using combinations of the up, down, right, and left arrow keys. Notice that you can only move the cursor across already existing text or input spaces.

If you're using vi from a remote terminal, the arrow keys may not work correctly. This will depend on your terminal emulator. If the arrow keys don't work in your case, you can use the following substitutes:

• To move left, press h.

• To move right, press l.

• To move down, press j.

• To move up, press k.

Moving One Word

Press w ("word") to move the cursor to the right one word at a time.

Press b ("back") to move the cursor to the left one word at a time.

Press W or B to move the cursor past the adjacent punctuation to the next or previous blank space.

Press e ("end") to move the cursor to the last character of the current word.

Moving to Start or End of Line

Press ^ to move the cursor to the start of the current line.

Press $ to move the cursor to the end of the current line.

Moving Down One Line

Press the Return key to move the cursor to the beginning of the next line down.

Moving Left

Press the Back Space key to move the cursor one character to the left.

Moving Right

Press the Space Bar to move the cursor one character to the right.

Moving to the Top

Press H ("high") to move the cursor to the top of the screen.

Moving to the Middle

Press M ("middle") to move the cursor to the middle of the screen.

Moving to the Bottom

Press L ("low") to move the cursor to the bottom of the screen.

6.5.1.2 Paging and Scrolling

If you move down when the cursor is at the bottom of the screen, or move up when the cursor is at the top of the screen, you will see the text scroll up or down. This can be an effective way to display more text in a very short file, but it can be tedious to move this way through a long file.

You may have noticed that moving the cursor either past the bottom or past the top of the screen has the effect of scrolling text up or down. This works for a very short file, but it is a tedious way to move through a long file.

You can page or scroll backward or forward through a file, a screen or a half-screen at a time. (To try out these commands on paint, you might want to add text so you have a longer file to work with.)

Note that there is a fundamental difference between paging and scrolling. Scrolling actually scrolls the cursor up or down through the text a line at a time, as though it were on a paper scroll. Paging moves the cursor up or down through the text a screenful at a time. On a fast system, you might not notice the difference. However, if you're working from a remote terminal or in some other situation where your system is running slower than usual, this difference can become painfully apparent.

Page Forward One Screen

To scroll forward (move down) one screenful, press Ctrl-F. (Hold down the Control key and press the F key.) The cursor moves to the upper left corner of the new screen.

Scroll Forward One-Half Screen

To scroll forward one half of a screen, press Ctrl-D.

Page Backward One Screen

To scroll backward (i.e., move up) one screenful, press Ctrl-B.

Scroll Backward One-Half Screen

To scroll backward one half of a screen, press Ctrl-U.

6.5.2 Inserting Text

vi provides many commands for inserting text. This section introduces you to the most useful of these commands. Note that each of these commands places vi in entry mode. To use any of these commands, you must first be in command mode. Remember to press Esc to make sure you are in command mode.

6.5.2.1 Append

Type a (append) to insert text to the right of the cursor. Experiment by moving the cursor anywhere on a line and typing a, followed by the text you want to add. Press Esc when you're finished.

Type A to add text to the end of a line. To see how this works, position the cursor anywhere on a text line and type A. The cursor will move to the end of the line, where you can type your additions. Press Esc when you're done.

6.5.2.2 Insert

Insert text to the left of the cursor by typing i from command mode.

Type I to insert text at the beginning of a line. (The command will move the cursor from any position on that line.) Again, as with all the commands in this section, press Esc to return to command mode after entering the desired text.

6.5.2.3 Open Line

Use these commands to open new lines, either above or below the current cursor position.

Type o to open a line below the current cursor position. To experiment, type o followed by a bit of text. You can enter several lines of text if you like. Press Esc when you are finished.

Type O to open a line above the current cursor position.

6.5.3 Changing Text

Changing text involves substituting one section of text for another. vi has several ways to do this, depending on circumstances.

6.5.3.1 Changing a Word

To replace a word, position the cursor at the beginning of the word to be replaced. Type cw, followed by the new word. To finish, press Esc.

To change part of a word, place the cursor on the word, to the right of the portion to be saved. Type cw, enter the correction, and press Esc.

6.5.3.2 Changing a Line

To replace a line, position the cursor anywhere on the line and type cc. The line disappears, leaving a blank line for your new text (which can be of any length). Press Esc to finish.

6.5.3.3 Changing Part of a Line

To replace part of a line, place the cursor to the right of the portion to be saved. Type C, enter the correction, and press Esc. This changes the portion of the line from the current cursor position to the end of the line.

6.5.3.4 Substituting Character(s)

To substitute one or more characters for the character under the cursor, type s, followed by the new text. Press Esc to return to command mode.

6.5.3.5 Replacing One Character

Use this command to replace the character highlighted by the cursor with another character. Position the cursor over the character and type r, followed by just one replacement character. After the substitution, vi automatically returns to command mode (there's no need to press Esc).

6.5.3.6 Transposing Characters

Correcting transposed characters takes just two keystrokes in vi. Suppose you find that you've typed "teh" when you meant to enter "the". Make the correction by putting the cursor over the first letter to be moved (in this case, e), and then type xp. The e and h will trade places - and vi will automatically return to command mode.

6.5.3.7 Breaking or Joining Lines

To break a line without affecting text, move the cursor to a space where you want the line to break and type r (for "replace") followed by Return. Note that if you type r with the cursor on a character and then press Return, that character will be replaced by the Return.

To join two lines, place the cursor on the upper line and type an uppercase J. (There's no need to press Esc after typing J.)

6.5.4 Undoing Changes

When editing text and making changes to a vi file, there will no doubt be times when you'll wish that you had not changed something. vi's undo commands allow you to back up one operation and continue on from there.

6.5.4.1 Undoing the Previous Command

If you make a mistake in vi or if you just change your mind once an operation is completed, you can undo your last command by pressing u immediately after the command. (There's no need to press Esc after typing u.) Pressing u a second time undoes the undo.

6.5.4.2 Undoing Changes to a Line

Type U to undo all changes you've made to a line. This command works only if you haven't moved the cursor off the line. (There's no need to press Esc after typing U.)

6.5.5 Deleting Text

These vi commands delete the character, word, or line you indicate. vi stays in command mode, so any subsequent text insertions must be preceded by additional commands to enter entry mode.

6.5.5.1 Deleting One Character

To delete one character, position the cursor over the character to be deleted and type x.

The x command also deletes the space the character occupied--when a letter is removed from the middle of a word, the remaining letters will close up, leaving no gap. You can also delete blank spaces in a line with the x command.

To delete one character before (to the left of) the cursor, type X (uppercase).

6.5.5.2 Deleting a Word or Part of a Word

To delete a word, position the cursor at the beginning of the word and type dw. The word and the space it occupied are removed.

To delete part of a word, position the cursor on the word to the right of the part to be saved. Type dw to delete the rest of the word.

6.5.5.3 Deleting a Line

To delete a line, position the cursor anywhere on the line and type dd. The line and the space it occupied are removed.

6.5.5.4 Deleting Part of a Line

You can also delete part of a line.

To delete everything to the right of the cursor, position the cursor to the right of the part of the line you want to save, and type D.

To delete everything to the left of the cursor, position the cursor to the right of the part of the line you want to delete and type d0 (d-zero).

6.5.5.5 Deleting to the End of the File

To delete everything from the current line to the end of the file, type dG. This also deletes the line on which the cursor is located.

6.5.5.6 Deleting from Beginning of File

To delete everything from the beginning of the file to the current line, type d1G. This also deletes the line on which the cursor is located.

6.5.6 Copying and Moving Text -- Yank, Delete, and Put

Many word-processors allow you to "copy and paste" and "cut and paste" lines of text. The vi editor also includes these features. The vi command-mode equivalent of "copy and paste" is yank and put; the equivalent of "cut and paste" is delete and put.

The methods for copying or moving small blocks of text in vi involves using a combination of the yank, delete, and put commands.

6.5.6.1 Copying Lines

To copy a line requires two commands: yy or Y ("yank") and either p ("put below") or P ("put above"). Note that Y does the same thing as yy.

To yank one line, position the cursor anywhere on the line and type yy. Now move the cursor to the line above where you want the yanked line to be put (copied), and type p. A copy of the yanked line will appear in a new line below the cursor.

To place the yanked line in a new line above the cursor, type P.

The yy command works well with a count: to yank 11 lines, for example, just type 11yy. Eleven lines, counting down from the cursor, will be yanked, and vi indicates this with a message at the bottom of the screen: 11 lines yanked.

You can also use the P or p commands immediately after any of the deletion commands discussed earlier. This puts the text you deleted above or below the cursor, respectively.

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Caution -

Use only cursor-moving commands between yanking or deleting and putting. If you delete or yank any other text before putting the new text in place, the lines you yanked or deleted will be lost.

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6.5.6.2 Moving Lines

Moving lines also requires two commands: dd ("delete") and either p or P.

To move one line, position the cursor anywhere on the line and type dd. For example, to delete 5 lines, type 5dd.

Next, move the cursor to the line above where you want the deleted line reinserted and type p. This inserts the text on a new line below the cursor.

Alternatively, you can put the deleted line above the cursor by typing P.

6.5.6.3 Using Named Buffers

To repeatedly insert a group of lines in various places within a document, you can yank (or delete) the lines into a named buffer. You specify named buffers by preceding a command with double quotes (") and a name for the buffer. For example, to yank four lines into the named buffer a, type "a4yy". You can use several different buffers. For example, you might also delete text from one location and add it to several others. To delete 12 lines into the named buffer b, type "b12dd".

To insert the text, precede the p or P command with n, where n is the named buffer. For example, to insert the lines saved in buffer b, type "bP".

You can overwrite named buffers with new lines. The buffers are saved until you exit vi.

When you use named buffers, you can safely delete and yank other text without affecting the lines you have already saved in the named buffers -- unless, of course, you purposely overwrite the named buffer.

6.5.7 Using a Count to Repeat Commands

Many vi commands can be preceded by a repeat factor (called a count) -- a number that precedes the command and tells it how many times to repeat the operation.

Most of the commands in the previous sections take counts. For instance, 3dd repeats the command to delete a line three times, therefore deleting three lines. 2dw deletes two words, and 4x deletes four characters or spaces. You can also use counts with commands to move the cursor, such as 3w and 2Ctrl-F. This will all become evident as you learn the vi commands. In the section "6.12 Summary of Basic vi Commands"each command that takes a count is indicated by "[count]" before the command name.

Typing a period (.) repeats the previous text-changing command. For example, if you have just deleted a line with dd, you can move the cursor to another line and delete it by simply typing a period.