vi.beginner

早期freebsd实现

Section 1: {^F} {ZZ}

To get out of this tutorial, type: ZZ (two capital Z's).

Learning a new computer system implies learning a new text editor.  These
tutorial lessons were created by Dain Samples to help you come to grips with
UC Berkeley's screen oriented editor called vi (for VIsual). This tutorial
uses the vi editor itself as the means of presentation. 

For best use of this tutorial, read all of a screen before performing any of
the indicated actions.  This tutorial (or, at least, the first half of it) has
been designed to systematically present the vi commands IF THE INSTRUCTIONS
ARE FOLLOWED!  If you are too adventuresome, you may find yourself lost.  If
you ever find yourself stuck, remember the first line of this section.

OK, now find the control key on your keyboard; it usually has CTL or CTRL
written on its upper surface.  Your first assignment is to hold the control
key down while you press the 'F' key on your keyboard.  Please do so now.



Section 2: {^F} {^B}
Many of vi's commands use the control key and some other key in combination,
as with the control and the 'F' key above.  This is abbreviated CTL-F, or ^F.

As you have probably guessed by now, ^F (CTL-F) moves you forward a fixed
number of lines in the file.  Throughout the remainder of the tutorial when
you are ready to advance to the next section of text, hit ^F.

The opposite command is ^B.  Just for fun, you might want to try a ^B to see
the previous section again.  Be sure to do a ^F to return you here.

Determine what the cursor looks like on your screen.  Whatever it is (a box,
an underscore, blinking, flashing, inverse, etc.) it should now be positioned
in the upper left-hand corner of your screen under or on the S of Section.
Become familiar with your cursor: to use vi correctly it is important to
always know where the cursor is.

Did you notice that when you do a ^F the cursor is left at the top of the
screen, and a ^B leaves the cursor near the bottom of the screen?  Try the two
commands ^B^F again.  And now do another ^F to see the next section.

Section 3: {^F} {^B}
You now have two basic commands for examining a file, both forwards (^F) and
backwards (^B).

Note that these are vi text editing commands: they are not commands for the
tutorial.  Indeed, this tutorial is nothing but a text file which you are now
editing.  Everything you do and learn in this tutorial will be applicable to
editing text files.

Therefore, when you are editing a file and are ready to see more of the text,
entering ^F will get you to the next section of the file.  Entering ^B will
show you the previous section.

Time for you to do another ^F.







Section 4: {^F} {^B} {^M} (return key)
We will adopt the notation of putting commands in curly braces so we can write
them unambiguously.  For example, if you are to type the command sequence
"control B control F" (as we asked you to do above) it would appear as {^B^F}.
This allows clear delineation of the command strings from the text. Remember
that the curly braces are NOT part of the command string you are to type. Do
NOT type the curly braces.  

Sometimes, the command string in the curly braces will be rather long, and may
be such that the first couple of characters of the command will erase from
the screen the string you are trying to read and type.  It is suggested that
you write down the longer commands BEFORE you type them so you won't forget
them once they disappear.

Now locate the return key on your keyboard: it is usually marked 'RETURN',
indicate hitting the return key.  In fact, the control-M key sequence is
exactly the same as if you hit the return key, and vice versa.

Now type {^F}.


Section 5: {:q!} {ZZ} {^M} (return key)
Recognize that this tutorial is nothing more than a text file that you
are editing.  This means that if you do something wrong, it is possible
for you to destroy the information in this file.  Don't worry.  If this
happens, type {ZZ} (two capital Z's) or {:q!^M} to leave the tutorial.
Restart the tutorial.  Once in the tutorial, you can then page forward
with {^F} until you are back to where you want to be.  (There are
easier ways to do this, some of which will be discussed later, but this
is the most straightforward.)

You may want to write these commands down in a convenient place for quick
reference: {:q!^M} and {ZZ}

We will assume that you now know to do a {^F} to advance the file







Section 6: {m} {G} {'} {z}
Now that you know how to get around in the file via ^F and ^B let's look at
other ways of examining a text file.  Sometimes it is necessary, in the midst
of editing a file, to examine another part of the file.  You are then faced
with the problem of remembering your place in the file, looking at the other
text, and then getting back to your original location.  Vi has a 'mark'
command, m. Type {mp}.  You have just 'marked' your current location in the
file and given it the name 'p'.  The command string below will do three
things: position you at the beginning of the file (line 1), then return you to
the location 'p' that you just marked with the 'm' command, and, since the
screen will not look exactly the same as it does right now, the 'z' command
will reposition the screen. (You may want to write the string down before
typing it: once you type {1G} it will no longer be on the screen.)

So now type {1G'pz^M} - a one followed by a capital G, followed by the quote
mark, followed by a lower case 'p', then a lower case 'z', then a return
(which is the same as a ^M).  The {1G} moves you to line 1, i.e. the beginning
of the file.  The {'p} moves you to the location you marked with {mp}.  The
{z^M} command will repaint the screen putting the cursor at the top of the
screen. (Now {^F}.)

Section 7: {m} {G} {'} {z}
Let's look at some variations on those commands.  If you wanted to look at
line 22 in the file and return to this location you could type {mp22G'p}.  Do
so now, observing that {22G} puts your cursor at the beginning of section 2 in
the middle of the screen.

Also note that, without the {z^M} command, the line with 'Section 7' on it is
now in the MIDDLE of the screen, and not at the top.  Our cursor is on the
correct line (where we did the {mp} command) but the line is not where we
might like it to be on the screen.  That is the function of the {z^M} command.
(Remember, ^M is the same as the 'return' key on your keyboard.)  Type {z^M}
now and observe the effect.

As you can see, the 'Section 7' line is now at the top of the screen with the
cursor happily under the capital S.  If you would like the cursor line (i.e.
the line which the cursor is on) in the middle of the screen again, you would
type {z.}.  If you wanted the cursor line to be at the BOTTOM of the screen,
type {z-}.  Try typing {z-z.z^M} and watch what happens.

{^F}

Section 8: {z} {m} {'}

Note that the z command does not change the position of our cursor in the file
itself, it simply moves the cursor around on the screen by moving the contents
of the file around on the screen.  The cursor stays on the same line of the
file when using the z command.

This brings up an important point.  There are two questions that the users of
vi continually need to know the answer to: "Where am I in the file?" and
"Where am I on the screen?"  The cursor on your terminal shows the answer to
both questions.  Some commands will move you around in the file, usually
changing the location of the cursor on the screen as well.  Other commands
move the cursor around on the screen without changing your location in the
file.

Now type {ma}.  Your location in the file has been given the name 'a'. If you
type {'p'a} you will see the previous location we marked in section 7, and
then will be returned to the current location.  (You will want to do a {z^M}
to repaint the screen afterwards.)  Try it.  
{^F}

Section 9: {m} {''}
Now we can move about in our file pretty freely.  By using the {m} command we
can give the current cursor position a lower-case-character name, like 'p',
'a', 'e', 'm', or 'b'.  Using the {G} command preceded by a line number we can
look at any line in the file we like.  Using the single quote command {'}
followed by a character used in an {m} command, we can return to any location
in the file we have marked.

However, try {m3}, or {mM}.  You should hear a beep, or bell.  Only lower-case
letters are acceptable to the {m} and {'} commands: numbers, upper-case
letters, and special characters are not acceptable.

If you type the {'} command with a character that is lower-case alphabetic but
that has not been used in an {m} command, or for which the 'marked' text has
been deleted, you will also get a beep.  Try {'i}.  You should get a beep
because the command {mi} has never been issued.  (Unless you've been
experimenting.)

The command {''} attempts to return you to the location at which you last
modified some part of your file.  However, my experience has been that it is
difficult to predict exactly where you will end up.  
Section 10: {^M} {-}
Now do {ma}, marking your position at the top of the screen.  Now hit {^M} (or
return) until the cursor is right ... 
* <- here, over/under the asterisk.  Now
type {mb'a'b} and watch the cursor move from the asterisk to the top of the
screen and back again.

The {^M} command moves the cursor to the beginning of the next line.  Now type
{^M} until the cursor is right ...
* <- here.  The command to move the cursor to the beginning of the
previous line is {-}.  Practice moving the cursor around on the screen by using
{^M} and {-}.  BE CAREFUL to not move the cursor OFF the screen just yet.  If
you do, type {'az^M}.

Now we can move to any line within the screen.  Practice moving around in the
file using the {^F}, {^B}, {-}, {^M}, {z}, and {'} commands.  When you are
fairly confident that you can get to where you need to be in the file, and
position the cursor on the screen where you want it type {'az^M^F} (which, of
course, moves you back to the beginning of this section, repositions the
cursor at the top of the screen, and advances you to the next section).

Section 11: scrolling: {^M}
The cursor should now be on the S of 'Section 11', and this should be on the
first line of the screen.  If it is not, do {^M} or {-} as appropriate to put
the cursor on the section line, and type {z^M}.

Type {mc} to mark your place.

Now type {^M} until the cursor is on the last line of this screen.  Now do one
more {^M} and observe the result.  This is called scrolling.  When you
attempted to move to a line not displayed on the screen, the line at the top of
the screen was 'scrolled off', and a line at the bottom of the screen was
'scrolled on'.  The top line with 'Section 11' should no longer be visible.

Now type {'cz^M} to reset the screen and type {^F} for the next section.







Section 12: {-} {z}

The {-} command moves the cursor to the previous line in the file.  Now type
{-}, which attempts to move the cursor to the previous line in this file.
However, that line is not on the screen.  The resulting action will depend on
your terminal.  (Do a {^Mz^M} to reposition the file).  On intelligent
terminals (e.g. VT100s, Z19s, Concept 100s), a top line is 'scrolled on' and
the bottom line is 'scrolled off'.  Other terminals, however, may not have
this 'reverse scrolling' feature.  They will simply repaint the screen with
the cursor line in the middle of the screen.  On such terminals it is
necessary to type {z^M} to get the cursor line back to the top of the screen.