 | Chapter 3 |  |
| Chapter 3 | |
You will not use vi only to create new files. You'll spend a lot of your time in vi editing existing files. You rarely want to simply open to the first line in the file and move through it line by line. You want to get to a specific place in a file and start work.
All edits begin by moving the cursor to where you want to begin the edit (or, with ex line editor commands, by identifying the line numbers to be edited). This chapter shows you how to think about movement in a variety of ways (by screens, by text, by patterns, or by line numbers). There are many ways to move in vi, since editing speed depends on getting to your destination with only a few keystrokes.
This chapter covers:
Movement by screens.
Movement by text blocks.
Movement by searches for patterns.
Movement by line number.
When you read a book, you think of "places" in the book by page: the page where you stopped reading or the page number in an index. You don't have this convenience when you're editing files. Some vi files take up only a few lines, and you can see the whole file at once. But many files have hundreds of lines.
You can think of a vi file as text on a long roll of paper. The screen is a window of (usually) 24 lines of text on that long roll.
In insert mode, as you fill up the screen with text, you will end up typing on the bottom line of the screen. When you reach the end and press [RETURN], the top line rolls out of sight, and a blank line appears on the bottom of the screen for new text. This is called scrolling.
In command mode, you can move through a file to see any text in it by scrolling the screen ahead or back. And, since cursor movements can be multiplied by numeric prefixes, you can move quickly to anywhere in your file.
[CTRL] [F] There are vi commands to scroll forward and backward through the file by full and half screens:
^F | Scroll forward one screen. |
^B | Scroll backward one screen. |
^D | Scroll forward half screen (down). |
^U | Scroll backward half screen (up). |
(In the list of commands above, the ^ symbol represents the
[CTRL]
key. ^F means to hold down the
[CTRL]
key and press the f key simultaneously.)
There are also
commands to scroll the screen up one line (^E) and down one line
(^Y).
However, these two commands do not send the cursor to the beginning
of the line.
The cursor remains at the same point in the line as when the command
was issued.
[z]
If you want to scroll the screen up or down, but you want the cursor
to remain on the line where you left it, use the z command.
z[RETURN] | Move current line to top of screen and scroll. |
z. | Move current line to center of screen and scroll. |
z- | Move current line to bottom of screen and scroll. |
z command, using a numeric prefix as a
multiplier makes no sense. (After all, you would need to
reposition the cursor to the top of the screen only
once. Repeating the same z command wouldn't
move anything.)
Instead, z understands a numeric prefix as a
line number that it will use in place of the current
line. For example, z
[RETURN]
moves the current line to the top of the screen, but
200z
[RETURN]
moves line 200 to the top of the screen.Sometimes while you're editing, messages from your computer system will display on your screen. These messages don't become part of your editing buffer, but they do interfere with your work. When system messages appear on your screen, you need to redisplay, or redraw, the screen.
Whenever you scroll, you redraw part of (or all of) the screen, so you can always get rid of unwanted messages by scrolling them off the screen and then returning to your previous position. But you can also redraw the screen without scrolling, by typing [CTRL-L] or [CTRL-R]. [CTRL-R] is useful when you're editing on a dumb terminal or at a slow baud rate (such as when working via a modem).
[H] You can also keep your current screen, or view of the file, and move around within the screen using:
HMove to home - top line on screen.
MMove to middle line on screen.
LMove to last line on screen.
HMove to n lines below top line.
LMove to n lines above last line.
H moves the cursor from anywhere on the screen to the
first, or "home," line.
M moves to the middle line, L to the last.
To move to the line below the first line, use 2H.
| Keystrokes | Results |
|---|---|
L | With a screen editor you can scroll the page, move the cursor, delete lines, insert characters, and more, while seeing the results of your edits as you make them. Screen editors are very popular, since they allow you to make changes as you read through a file. |
Move to the last line of the screen with the
| |
2H | With a screen editor you can scroll the page, move the cursor, delete lines, insert characters, and more, while seeing the results of your edits as you make them. Screen editors are very popular, since they allow you to make changes as you read through a file. |
Move to the second line of the screen with the |
[RETURN]
Within the current screen there are also commands to move by line.
You've already seen j and k.
You can also use:
Move to first character of next line.
+Move to first character of next line.
-Move to first character of previous line.
The above three commands move down or up to the first
character of the line, ignoring any spaces or tabs.
j and k, by contrast, move the cursor down or up to
the first position of a line, even if that position is blank (and
assuming that the cursor started at the first position).
Don't forget that h and l move the cursor to the left
and right and that 0 and $ move the cursor to the
beginning or end of the line. You can also use:
^Move to first nonblank character of current line.
|Move to column n of current line.
As with the line movement commands above,
^ moves to the first character
of the line, ignoring any spaces or tabs.
0, by contrast, moves to the first position of the line, even if
that position is blank.
|  | |
| 2.6 Review of Basic vi Commands |  | 3.2 Movement by Text Blocks |
