vi.in

早期freebsd实现

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.\"	@(#)vi.in	8.2 (Berkeley) 4/20/94
.\"
.EH 'USD:11-%''An Introduction to Display Editing with Vi'
.OH 'An Introduction to Display Editing with Vi''USD:11-%'
.bd S 3
.if t .ds dg \(dg
.if n .ds dg +
.if t .ds dd \(dd
.if n .ds dd ++
.\".RP
.TL
An Introduction to Display Editing with Vi
.AU
William Joy
.AU
Mark Horton
.AI
Computer Science Division
Department of Electrical Engineering and Computer Science
University of California, Berkeley
Berkeley, Ca.  94720
.AB
.PP
.I Vi
(visual) is a display oriented interactive text editor.
When using
.I vi
the screen of your terminal acts as a window into the file which you
are editing.  Changes which you make to the file are reflected
in what you see.
.PP
Using
.I vi
you can insert new text any place in the file quite easily.
Most of the commands to
.I vi
move the cursor around in the file.
There are commands to move the cursor
forward and backward in units of characters, words,
sentences and paragraphs.
A small set of operators, like
.B d
for delete and
.B c
for change, are combined with the motion commands to form operations
such as delete word or change paragraph, in a simple and natural way.
This regularity and the mnemonic assignment of commands to keys makes the
editor command set easy to remember and to use.
.PP
.I Vi
will work on a large number of display terminals,
and new terminals are easily driven after editing a terminal description file.
While it is advantageous to have an intelligent terminal which can locally
insert and delete lines and characters from the display, the editor will
function quite well on dumb terminals over slow phone lines.
The editor makes allowance for the low bandwidth in these situations
and uses smaller window sizes and
different display updating algorithms to make best use of the
limited speed available.
.PP
It is also possible to use the command set of
.I vi
on hardcopy terminals, storage tubes and ``glass tty's'' using a one line
editing window; thus
.I vi's
command set is available on all terminals.
The full command set of the more traditional, line
oriented editor
.I ex
is available within
.I vi;
it is quite simple to switch between the two modes of editing.
.AE
.NH 1
Getting started
.PP
.FS
The financial support of an \s-2IBM\s0 Graduate Fellowship and the
National Science Foundation under grants MCS74-07644-A03 and MCS78-07291
is gratefully acknowledged.
.FE
This document provides a quick introduction to
.I vi.
(Pronounced \fIvee-eye\fP.)
You should be running
.I vi
on a file you are familiar with while you are reading this.
The first part of this document (sections 1 through 5)
describes the basics of using
.I vi.
Some topics of special interest are presented in section 6, and 
some nitty-gritty details of how the editor functions are saved for section
7 to avoid cluttering the presentation here.
.PP
There is also a short appendix here, which gives for each character the
special meanings which this character has in \fIvi\fR.  Attached to
this document should be a quick reference card.
This card summarizes the commands of
.I vi
in a very compact format.  You should have the card handy while you are
learning
.I vi.
.NH 2
Specifying terminal type
.PP
Before you can start
.I vi
you must tell the system what kind of terminal you are using.
Here is a (necessarily incomplete) list of terminal type codes.
If your terminal does not appear here, you should consult with one of
the staff members on your system to find out the code for your terminal.
If your terminal does not have a code, one can be assigned and a description
for the terminal can be created.
.LP
.TS
center;
ab ab ab
a a a.
Code	Full name	Type
_
2621	Hewlett-Packard 2621A/P	Intelligent
2645	Hewlett-Packard 264x	Intelligent
act4	Microterm ACT-IV	Dumb
act5	Microterm ACT-V	Dumb
adm3a	Lear Siegler ADM-3a	Dumb
adm31	Lear Siegler ADM-31	Intelligent
c100	Human Design Concept 100	Intelligent
dm1520	Datamedia 1520	Dumb
dm2500	Datamedia 2500	Intelligent
dm3025	Datamedia 3025	Intelligent
fox	Perkin-Elmer Fox	Dumb
h1500	Hazeltine 1500	Intelligent
h19	Heathkit h19	Intelligent
i100	Infoton 100	Intelligent
mime	Imitating a smart act4	Intelligent
t1061	Teleray 1061	Intelligent
vt52	Dec VT-52	Dumb
.TE
.PP
Suppose for example that you have a Hewlett-Packard HP2621A
terminal.  The code used by the system for this terminal is `2621'.
In this case you can use one of the following commands to tell the system
the type of your terminal:
.DS
% \fBsetenv TERM\fP 2621
.DE
This command works with the
.I csh
shell.
If you are using the standard Bourne shell
.I sh
then you should give the commands
.DS
$ \fBTERM=\fP2621
$ \fBexport TERM\fP
.DE
.PP
If you want to arrange to have your terminal type set up automatically
when you log in, you can use the
.I tset
program.
If you dial in on a
.I mime ,
but often use hardwired ports, a typical line for your
.I .login
file (if you use csh) would be
.DS
\fBsetenv TERM \(gatset\fP \- \-d mime\(ga
.DE
or for your
.I .profile
file (if you use sh)
.DS
\fBTERM=\(gatse\fPt \- \-d mime\(ga
.DE
.I Tset
knows which terminals are hardwired to each port
and needs only to be told that when you dial in you
are probably on a
.I mime .
.I Tset
is usually used to change the erase and kill characters, too.
.NH 2
Editing a file
.PP
After telling the system which kind of terminal you have, you should
make a copy of a file you are familiar with, and run
.I vi
on this file, giving the command
.DS
% \fBvi\fR \fIname\fR
.DE
replacing \fIname\fR with the name of the copy file you just created.
The screen should clear and the text of your file should appear on the
screen.  If something else happens refer to the footnote.\*(dd
.FS
\*(dd If you gave the system an incorrect terminal type code then the
editor may have just made a mess out of your screen.  This happens when
it sends control codes for one kind of terminal to some other
kind of terminal.  In this case hit
the keys \fB:q\fR (colon and the q key) and then hit the \s-2RETURN\s0 key.
This should get you back to the command level interpreter.
Figure out what you did wrong (ask someone else if necessary) and try again.
     Another thing which can go wrong is that you typed the wrong file name and
the editor just printed an error diagnostic.  In this case you should
follow the above procedure for getting out of the editor, and try again
this time spelling the file name correctly.
     If the editor doesn't seem to respond to the commands which you type
here, try sending an interrupt to it by hitting the \s-2DEL\s0 or \s-2RUB\s0
key on your terminal, and then hitting the \fB:q\fR command again followed
by a carriage return.
.sp
.FE
.NH 2
The editor's copy: the buffer
.PP
The editor does not directly modify the file which you are editing. 
Rather, the editor makes a copy of this file, in a place called the
.I buffer,
and remembers the file's
name.  You do not affect the contents of the file unless and until you
write the changes you make back into the original file.
.NH 2
Notational conventions
.PP
In our examples, input which must be typed as is will be presented in
\fBbold face\fR. Text which should be replaced with appropriate input
will be given in \fIitalics\fR.  We will represent special characters
in \s-2SMALL CAPITALS\s0.
.NH 2
Arrow keys
.PP
The editor command set is independent of the terminal
you are using.  On most terminals with cursor positioning keys, these keys
will also work within the editor.
If you don't have cursor positioning keys, or even if you do, you can use
the \fBh j k\fR and \fBl\fR keys as cursor positioning
keys (these are labelled with arrows on an
.I adm3a).*
.PP
(Particular note for the HP2621: on this terminal the function keys
must be \fIshifted\fR (ick) to send to the machine, otherwise they
only act locally.  Unshifted use will leave the cursor positioned
incorrectly.)
.FS
* As we will see later,
.I h
moves back to the left (like control-h which is a backspace),
.I j
moves down (in the same column),
.I k
moves up (in the same column),
and
.I l
moves to the right.
.FE
.NH 2
Special characters: \s-2ESC\s0, \s-2CR\s0 and \s-2DEL\s0
.PP
Several of these special characters are very important, so be sure to
find them right now.  Look on your keyboard for a key labelled \s-2ESC\s0
or \s-2ALT\s0.  It should be near the upper left corner of your terminal.
Try hitting this key a few times.  The editor will ring the bell
to indicate that it is in a quiescent state.\*(dd
.FS
\*(dd On smart terminals where it is possible, the editor will quietly
flash the screen rather than ringing the bell.
.FE
Partially formed commands are cancelled by \s-2ESC\s0, and when you insert
text in the file you end the text insertion
with \s-2ESC\s0.  This key is a fairly
harmless one to hit, so you can just hit it if you don't know
what is going on until the editor rings the bell.
.PP
The \s-2CR\s0 or \s-2RETURN\s0 key is important because it is used
to terminate certain commands.
It is usually at the right side of the keyboard,
and is the same command used at the end of each shell command.
.PP
Another very useful key is the \s-2DEL\s0 or \s-2RUB\s0 key, which generates
an interrupt, telling the editor to stop what it is doing.
It is a forceful way of making the editor listen
to you, or to return it to the quiescent state if you don't know or don't
like what is going on.  Try hitting the `/' key on your terminal.  This
key is used when you want to specify a string to be searched for.  The
cursor should now be positioned at the bottom line of the terminal after
a `/' printed as a prompt.  You can get the cursor back to the current
position by hitting the \s-2DEL\s0 or \s-2RUB\s0 key; try this now.*
.FS
* Backspacing over the `/' will also cancel the search.
.FE
From now on we will simply refer to hitting the \s-2DEL\s0 or \s-2RUB\s0
key as ``sending an interrupt.''**
.FS
** On some systems, this interruptibility comes at a price: you cannot type
ahead when the editor is computing with the cursor on the bottom line.
.FE
.PP
The editor often echoes your commands on the last line of the terminal.
If the cursor is on the first position of this last line, then the editor
is performing a computation, such as computing a new position in the
file after a search or running a command to reformat part of the buffer.
When this is happening you can stop the editor by
sending an interrupt.
.NH 2
Getting out of the editor
.PP
After you have worked with this introduction for a while, and you wish
to do something else, you can give the command \fBZZ\fP
to the editor.