vi.in

早期freebsd实现

.PP
You can edit a different file without leaving the editor by giving the
command \fB:e\fR\ \fIname\fR\s-2CR\s0.  If you have not written out
your file before you try to do this, then the editor will tell you this,
and delay editing the other file.  You can then give the command
\fB:w\fR\s-2CR\s0 to save your work and then the \fB:e\fR\ \fIname\fR\s-2CR\s0
command again, or carefully give the command \fB:e!\fR\ \fIname\fR\s-2CR\s0,
which edits the other file discarding the changes you have made to the
current file.
To have the editor automatically save changes,
include
.I "set autowrite"
in your EXINIT,
and use \fB:n\fP instead of \fB:e\fP.
.NH 2
Escaping to a shell
.PP
You can get to a shell to execute a single command by giving a
.I vi
command of the form \fB:!\fIcmd\fR\s-2CR\s0.
The system will run the single command
.I cmd
and when the command finishes, the editor will ask you to hit a \s-2RETURN\s0
to continue.  When you have finished looking at the output on the screen,
you should hit \s-2RETURN\s0 and the editor will clear the screen and
redraw it.  You can then continue editing.
You can also give another \fB:\fR command when it asks you for a \s-2RETURN\s0;
in this case the screen will not be redrawn.
.PP
If you wish to execute more than one command in the shell, then you can
give the command \fB:sh\fR\s-2CR\s0.
This will give you a new shell, and when you finish with the shell, ending
it by typing a \fB^D\fR, the editor will clear the screen and continue.
.PP
On systems which support it, \fB^Z\fP will suspend the editor
and return to the (top level) shell.
When the editor is resumed, the screen will be redrawn.
.NH 2
Marking and returning
.PP
The command \fB\(ga\(ga\fR returned to the previous place
after a motion of the cursor by a command such as \fB/\fR, \fB?\fR or
\fBG\fR.  You can also mark lines in the file with single letter tags
and return to these marks later by naming the tags.  Try marking the
current line with the command \fBm\fR\fIx\fR, where you should pick some
letter for \fIx\fR, say `a'.  Then move the cursor to a different line
(any way you like) and hit \fB\(gaa\fR.  The cursor will return to the
place which you marked.
Marks last only until you edit another file.
.PP
When using operators such as
.B d
and referring to marked lines, it is often desirable to delete whole lines
rather than deleting to the exact position in the line marked by \fBm\fR.
In this case you can use the form \fB\(aa\fR\fIx\fR rather than
\fB\(ga\fR\fIx\fR.  Used without an operator, \fB\(aa\fR\fIx\fR will move to
the first non-white character of the marked line; similarly \fB\(aa\(aa\fR
moves to the first non-white character of the line containing the previous
context mark \fB\(ga\(ga\fR.
.NH 2
Adjusting the screen
.PP
If the screen image is messed up because of a transmission error to your
terminal, or because some program other than the editor wrote output
to your terminal, you can hit a \fB^L\fR, the \s-2ASCII\s0 form-feed
character, to cause the screen to be refreshed.
.PP
On a dumb terminal, if there are @ lines in the middle of the screen
as a result of line deletion, you may get rid of these lines by typing
\fB^R\fR to cause the editor to retype the screen, closing up these holes.
.PP
Finally, if you wish to place a certain line on the screen at the top
middle or bottom of the screen, you can position the cursor to that line,
and then give a \fBz\fR command.
You should follow the \fBz\fR command with a \s-2RETURN\s0 if you want
the line to appear at the top of the window, a \fB.\fR if you want it
at the center, or a \fB\-\fR if you want it at the bottom.
.NH 1
Special topics
.NH 2
Editing on slow terminals
.PP
When you are on a slow terminal, it is important to limit the amount
of output which is generated to your screen so that you will not suffer
long delays, waiting for the screen to be refreshed.  We have already
pointed out how the editor optimizes the updating of the screen during
insertions on dumb terminals to limit the delays, and how the editor erases
lines to @ when they are deleted on dumb terminals.
.PP
The use of the slow terminal insertion mode is controlled by the
.I slowopen
option.  You can force the editor to use this mode even on faster terminals
by giving the command \fB:se slow\fR\s-2CR\s0.  If your system is sluggish
this helps lessen the amount of output coming to your terminal.
You can disable this option by \fB:se noslow\fR\s-2CR\s0.
.PP
The editor can simulate an intelligent terminal on a dumb one.  Try
giving the command \fB:se redraw\fR\s-2CR\s0.  This simulation generates
a great deal of output and is generally tolerable only on lightly loaded
systems and fast terminals.  You can disable this by giving the command
 \fB:se noredraw\fR\s-2CR\s0.
.PP
The editor also makes editing more pleasant at low speed by starting
editing in a small window, and letting the window expand as you edit.
This works particularly well on intelligent terminals.  The editor can
expand the window easily when you insert in the middle of the screen
on these terminals.  If possible, try the editor on an intelligent terminal
to see how this works.
.PP
You can control the size of the window which is redrawn each time the
screen is cleared by giving window sizes as argument to the commands
which cause large screen motions:
.DS
.B ":  /  ?  [[  ]]  \(ga  \(aa"
.DE
Thus if you are searching for a particular instance of a common string
in a file you can precede the first search command by a small number,
say 3, and the editor will draw three line windows around each instance
of the string which it locates.
.PP
You can easily expand or contract the window, placing the current line
as you choose, by giving a number on a \fBz\fR command, after the \fBz\fR
and before the following \s-2RETURN\s0, \fB.\fR or \fB\-\fR.  Thus the
command \fBz5.\fR redraws the screen with the current line in the center
of a five line window.\*(dg
.FS
\*(dg Note that the command \fB5z.\fR has an entirely different effect,
placing line 5 in the center of a new window.
.FE
.PP
If the editor is redrawing or otherwise updating large portions of the
display, you can interrupt this updating by hitting a \s-2DEL\s0 or \s-2RUB\s0
as usual.  If you do this you may partially confuse the editor about
what is displayed on the screen.  You can still edit the text on
the screen if you wish; clear up the confusion
by hitting a \fB^L\fR; or move or search again, ignoring the
current state of the display.
.PP
See section 7.8 on \fIopen\fR mode for another way to use the
.I vi
command set on slow terminals.
.NH 2
Options, set, and editor startup files
.PP
The editor has a set of options, some of which have been mentioned above.
The most useful options are given in the following table.
.KF
.TS
lb lb lb lb
l l l a.
Name	Default	Description
_
autoindent	noai	Supply indentation automatically
autowrite	noaw	Automatic write before \fB:n\fR, \fB:ta\fR, \fB^\(ua\fR, \fB!\fR
ignorecase	noic	Ignore case in searching
lisp	nolisp	\fB( { ) }\fR commands deal with S-expressions
list	nolist	Tabs print as ^I; end of lines marked with $
magic	nomagic	The characters . [ and * are special in scans
number	nonu	Lines are displayed prefixed with line numbers
paragraphs	para=IPLPPPQPbpP LI	Macro names which start paragraphs
redraw	nore	Simulate a smart terminal on a dumb one
sections	sect=NHSHH HU	Macro names which start new sections
shiftwidth	sw=8	Shift distance for <, > and input \fB^D\fP and \fB^T\fR
showmatch	nosm	Show matching \fB(\fP or \fB{\fP as \fB)\fP or \fB}\fR is typed
slowopen	slow	Postpone display updates during inserts
term	dumb	The kind of terminal you are using.
.TE
.KE
.PP
The options are of three kinds:  numeric options, string options, and
toggle options.  You can set numeric and string options by a statement
of the form
.DS
\fBset\fR \fIopt\fR\fB=\fR\fIval\fR
.DE
and toggle options can be set or unset by statements of one of the forms
.DS
\fBset\fR \fIopt\fR
\fBset\fR \fBno\fR\fIopt\fR
.DE
These statements can be placed in your EXINIT in your environment,
or given while you are running
.I vi
by preceding them with a \fB:\fR and following them with a \s-2CR\s0.
.PP
You can get a list of all options which you have changed by the
command \fB:set\fR\s-2CR\s0, or the value of a single option by the
command \fB:set\fR \fIopt\fR\fB?\fR\s-2CR\s0.
A list of all possible options and their values is generated by
\fB:set all\fP\s-2CR\s0.
Set can be abbreviated \fBse\fP.
Multiple options can be placed on one line, e.g.
\fB:se ai aw nu\fP\s-2CR\s0.
.PP
Options set by the \fBset\fP command only last
while you stay in the editor.
It is common to want to have certain options set whenever you
use the editor.
This can be accomplished by creating a list of \fIex\fP commands\*(dg
.FS
\*(dg
All commands which start with
.B :
are \fIex\fP commands.
.FE
which are to be run every time you start up \fIex\fP, \fIedit\fP,
or \fIvi\fP.
A typical list includes a \fBset\fP command, and possibly a few
\fBmap\fP commands.
Since it is advisable to get these commands on one line, they can
be separated with the | character, for example:
.DS
\fBset\fP ai aw terse|\fBmap\fP @ dd|\fBmap\fP # x
.DE
which sets the options \fIautoindent\fP, \fIautowrite\fP, \fIterse\fP,
(the
.B set
command),
makes @ delete a line,
(the first
.B map ),
and makes # delete a character,
(the second
.B map ).
(See section 6.9 for a description of the \fBmap\fP command)
This string should be placed in the variable EXINIT in your environment.
If you use the shell \fIcsh\fP,
put this line in the file
.I .login
in your home directory:
.DS
setenv EXINIT \(aa\fBset\fP ai aw terse|\fBmap\fP @ dd|\fBmap\fP # x\(aa
.DE
If you use the standard shell \fIsh\fP,
put these lines in the file
.I .profile
in your home directory:
.DS
EXINIT=\(aa\fBset\fP ai aw terse|\fBmap\fP @ dd|\fBmap\fP # x\(aa
export EXINIT
.DE
Of course, the particulars of the line would depend on which options
you wanted to set.
.NH 2
Recovering lost lines
.PP
You might have a serious problem if you delete a number of lines and then
regret that they were deleted.  Despair not, the editor saves the last
9 deleted blocks of text in a set of numbered registers 1\-9.
You can get the \fIn\fR'th previous deleted text back in your file by
the command
"\fR\fIn\fR\|\fBp\fR.
The "\fR here says that a buffer name is to follow,
\fIn\fR is the number of the buffer you wish to try
(use the number 1 for now),
and
.B p
is the put command, which puts text in the buffer after the cursor.
If this doesn't bring back the text you wanted, hit
.B u
to undo this and then
\fB\&.\fR
(period)
to repeat the put command.
In general the
\fB\&.\fR
command will repeat the last change you made.
As a special case, when the last command refers to a numbered text buffer,
the \fB.\fR command increments the number of the buffer before repeating
the command.  Thus a sequence of the form
.DS
\fB"1pu.u.u.\fR
.DE
will, if repeated long enough, show you all the deleted text which has
been saved for you.
You can omit the
.B u
commands here to gather up all this text in the buffer, or stop after any
\fB\&.\fR command to keep just the then recovered text.
The command
.B P
can also be used rather than
.B p
to put the recovered text before rather than after the cursor.
.NH 2
Recovering lost files
.PP
If the system crashes, you can recover the work you were doing
to within a few changes.  You will normally receive mail when you next
login giving you the name of the file which has been saved for you. 
You should then change to the directory where you were when the system
crashed and give a command of the form:
.DS
% \fBvi \-r\fR \fIname\fR
.DE
replacing \fIname\fR with the name of the file which you were editing.
This will recover your work to a point near where you left off.\*(dg
.FS
\*(dg In rare cases, some of the lines of the file may be lost.  The
editor will give you the numbers of these lines and the text of the lines
will be replaced by the string `LOST'.  These lines will almost always
be among the last few which you changed.  You can either choose to discard
the changes which you made (if they are easy to remake) or to replace
the few lost lines by hand.
.FE
.PP
You can get a listing of the files which are saved for you by giving
the command:
.DS
% \fBvi \-r\fR
.DE
If there is more than one instance of a particular file saved, the editor
gives you the newest instance each time you recover it.  You can thus
get an older saved copy back by first recovering the newer copies.
.PP
For this feature to work,
.I vi
must be correctly installed by a super user on your system,
and the
.I mail
program must exist to receive mail.
The invocation ``\fIvi -r\fP'' will not always list all saved files,
but they can be recovered even if they are not listed.
.NH 2
Continuous text input
.PP
When you are typing in large amounts of text it is convenient to have
lines broken near the right margin automatically.  You can cause this
to happen by giving the command
\fB:se wm=10\fR\s-2CR\s0.
This causes all lines to be broken at a space at least 10 columns
from the right hand edge of the screen.
.PP
If the editor breaks an input line and you wish to put it back together
you can tell it to join the lines with \fBJ\fR.  You can give \fBJ\fR
a count of the number of lines to be joined as in \fB3J\fR to join 3
lines.  The editor supplies white space, if appropriate,
at the juncture of the joined
lines, and leaves the cursor at this white space.
You can kill the white space with \fBx\fR if you don't want it.
.NH 2