vi.in

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is incorrect, you can replace it with the correct character by giving
the command \fBr\fR\fIc\fR,
where \fIc\fR is replaced by the correct character.
Finally if the character which is incorrect should be replaced
by more than one character, give the command \fBs\fR which substitutes
a string of characters, ending with \s-2ESC\s0, for it.
If there are a small number of characters
which are wrong you can precede \fBs\fR with a count of the number of
characters to be replaced.  Counts are also useful with \fBx\fR to specify
the number of characters to be deleted.
.NH 2
More corrections: operators
.PP
You already know almost enough to make changes at a higher level.
All you need to know now is that the 
.B d
key acts as a delete operator.  Try the command
.B dw
to delete a word.
Try hitting \fB.\fR a few times.  Notice that this repeats the effect
of the \fBdw\fR.  The command \fB.\fR repeats the last command which
made a change.  You can remember it by analogy with an ellipsis `\fB...\fR'.
.PP
Now try
\fBdb\fR.
This deletes a word backwards, namely the preceding word.
Try 
\fBd\fR\s-2SPACE\s0.  This deletes a single character, and is equivalent
to the \fBx\fR command.
.PP
Another very useful operator is
.B c
or change.  The command 
.B cw
thus changes the text of a single word.
You follow it by the replacement text ending with an \s-2ESC\s0.
Find a word which you can change to another, and try this
now.
Notice that the end of the text to be changed was marked with the character
`$' so that you can see this as you are typing in the new material.
.NH 2
Operating on lines
.PP
It is often the case that you want to operate on lines.
Find a line which you want to delete, and type 
\fBdd\fR,
the
.B d
operator twice.  This will delete the line.
If you are on a dumb terminal, the editor may just erase the line on
the screen, replacing it with a line with only an @ on it.  This line
does not correspond to any line in your file, but only acts as a place
holder.  It helps to avoid a lengthy redraw of the rest of the screen
which would be necessary to close up the hole created by the deletion
on a terminal without a delete line capability.
.PP
Try repeating the
.B c
operator twice; this will change a whole line, erasing its previous contents and
replacing them with text you type up to an \s-2ESC\s0.\*(dg
.FS
\*(dg The command \fBS\fR is a convenient synonym for for \fBcc\fR, by
analogy with \fBs\fR.  Think of \fBS\fR as a substitute on lines, while
\fBs\fR is a substitute on characters.
.FE
.PP
You can delete or change more than one line by preceding the
.B dd
or
.B cc
with a count, i.e. \fB5dd\fR deletes 5 lines.
You can also give a command like \fBdL\fR to delete all the lines up to
and including
the last line on the screen, or \fBd3L\fR to delete through the third from
the bottom line.  Try some commands like this now.*
.FS
* One subtle point here involves using the \fB/\fR search after a \fBd\fR.
This will normally delete characters from the current position to the
point of the match.  If what is desired is to delete whole lines
including the two points, give the pattern as \fB/pat/+0\fR, a line address.
.FE
Notice that the editor lets you know when you change a large number of
lines so that you can see the extent of the change.
The editor will also always tell you when a change you make affects text which
you cannot see.
.NH 2
Undoing
.PP
Now suppose that the last change which you made was incorrect;
you could use the insert, delete and append commands to put the correct
material back.  However, since it is often the case that we regret a
change or make a change incorrectly, the editor provides a
.B u
(undo) command to reverse the last change which you made.
Try this a few times, and give it twice in a row to notice that an
.B u
also undoes a
.B u.
.PP
The undo command lets you reverse only a single change.  After you make
a number of changes to a line, you may decide that you would rather have
the original state of the line back.  The
.B U
command restores the current line to the state before you started changing
it.
.PP
You can recover text which you delete, even if
undo will not bring it back; see the section on recovering lost text
below.
.NH 2
Summary
.IP
.TS
lw(.50i)b a.
\fR\s-2SPACE\s0\fP	advance the cursor one position
^H	backspace the cursor
^W	erase a word during an insert
\fRerase\fP	your erase (usually ^H or #), erases a character during an insert
\fRkill\fP	your kill (usually @, ^X, or ^U), kills the insert on this line
\&\fB.\fP	repeats the changing command
O	opens and inputs new lines, above the current
U	undoes the changes you made to the current line
a	appends text after the cursor
c	changes the object you specify to the following text
d	deletes the object you specify
i	inserts text before the cursor
o	opens and inputs new lines, below the current
u	undoes the last change
.TE
.NH 1
Moving about; rearranging and duplicating text
.NH 2
Low level character motions
.PP
Now move the cursor to a line where there is a punctuation or a bracketing
character such as a parenthesis or a comma or period.  Try the command
\fBf\fR\fIx\fR where \fIx\fR is this character.  This command finds
the next \fIx\fR character to the right of the cursor in the current
line.  Try then hitting a \fB;\fR, which finds the next instance of the
same character.  By using the \fBf\fR command and then a sequence of
\fB;\fR's you can often
get to a particular place in a line much faster than with a sequence
of word motions or \s-2SPACE\s0s.
There is also a \fBF\fR command, which is like \fBf\fR, but searches 
backward.  The \fB;\fR command repeats \fBF\fR also.
.PP
When you are operating on the text in a line it is often desirable to
deal with the characters up to, but not including, the first instance of
a character.  Try \fBdf\fR\fIx\fR for some \fIx\fR now and
notice that the \fIx\fR character is deleted.  Undo this with \fBu\fR
and then try \fBdt\fR\fIx\fR;  the \fBt\fR here stands for to, i.e.
delete up to the next \fIx\fR, but not the \fIx\fR.  The command \fBT\fR
is the reverse of \fBt\fR.
.PP
When working with the text of a single line, an \fB\(ua\fR moves the
cursor to the first non-white position on the line, and a
\fB$\fR moves it to the end of the line.  Thus \fB$a\fR will append new
text at the end of the current line.
.PP
Your file may have tab (\fB^I\fR) characters in it.  These
characters are represented as a number of spaces expanding to a tab stop,
where tab stops are every 8 positions.*
.FS
* This is settable by a command of the form \fB:se ts=\fR\fIx\fR\s-2CR\s0,
where \fIx\fR is 4 to set tabstops every four columns.  This has
effect on the screen representation within the editor.
.FE
When the cursor is at a tab, it sits on the last of the several spaces
which represent that tab.  Try moving the cursor back and forth over
tabs so you understand how this works.
.PP
On rare occasions, your file may have nonprinting characters in it. 
These characters are displayed in the same way they are represented in
this document, that is with a two character code, the first character
of which is `^'.  On the screen non-printing characters resemble a `^'
character adjacent to another, but spacing or backspacing over the character
will reveal that the two characters are, like the spaces representing
a tab character, a single character.
.PP
The editor sometimes discards control characters,
depending on the character and the setting of the
.I beautify
option,
if you attempt to insert them in your file.
You can get a control character in the file by beginning
an insert and then typing a \fB^V\fR before the control
character.  The
\fB^V\fR quotes the following character, causing it to be
inserted directly into the file.
.PP
.NH 2
Higher level text objects
.PP
In working with a document it is often advantageous to work in terms
of sentences, paragraphs, and sections.  The operations \fB(\fR and \fB)\fR
move to the beginning of the previous and next sentences respectively.
Thus the command \fBd)\fR will delete the rest of the current sentence;
likewise \fBd(\fR will delete the previous sentence if you are at the
beginning of the current sentence, or the current sentence up to where
you are if you are not at the beginning of the current sentence.
.PP
A sentence is defined to end at a `.', `!' or `?' which is followed by
either the end of a line, or by two spaces.  Any number of closing `)',
`]', `"' and `\(aa' characters may appear after the `.', `!' or `?' before
the spaces or end of line.
.PP
The operations \fB{\fR and \fB}\fR move over paragraphs and the operations
\fB[[\fR and \fB]]\fR move over sections.\*(dg
.FS
\*(dg The \fB[[\fR and \fB]]\fR operations
require the operation character to be doubled because they can move the
cursor far from where it currently is.  While it is easy to get back
with the command \fB\(ga\(ga\fP,
these commands would still be frustrating
if they were easy to hit accidentally.
.FE
.PP
A paragraph begins after each empty line, and also
at each of a set of paragraph macros, specified by the pairs of characters
in the definition of the string valued option \fIparagraphs\fR.
The default setting for this option defines the paragraph macros of the
\fI\-ms\fR and \fI\-mm\fR macro packages, i.e. the `.IP', `.LP', `.PP'
and `.QP', `.P' and `.LI' macros.\*(dd
.FS
\*(dd You can easily change or extend this set of macros by assigning a
different string to the \fIparagraphs\fR option in your EXINIT.
See section 6.2 for details.
The `.bp' directive is also considered to start a paragraph.
.FE
Each paragraph boundary is also a sentence boundary.  The sentence
and paragraph commands can
be given counts to operate over groups of sentences and paragraphs.
.PP
Sections in the editor begin after each macro in the \fIsections\fR option,
normally `.NH', `.SH', `.H' and `.HU', and each line with a formfeed \fB^L\fR
in the first column.
Section boundaries are always line and paragraph boundaries also.
.PP
Try experimenting with the sentence and paragraph commands until you are
sure how they work.  If you have a large document, try looking through
it using the section commands.
The section commands interpret a preceding count as a different window size in
which to redraw the screen at the new location, and this window size
is the base size for newly drawn windows until another size is specified.
This is very useful
if you are on a slow terminal and are looking for a particular section. 
You can give the first section command a small count to then see each successive
section heading in a small window.
.NH 2
Rearranging and duplicating text
.PP
The editor has a single unnamed buffer where the last deleted or
changed away text is saved, and a set of named buffers \fBa\fR\-\fBz\fR
which you can use to save copies of text and to move text around in
your file and between files.
.PP
The operator
.B y
yanks a copy of the object which follows into the unnamed buffer.
If preceded by a buffer name, \fB"\fR\fIx\fR\|\fBy\fR, where
\fIx\fR here is replaced by a letter \fBa\-z\fR, it places the text in the named
buffer.  The text can then be put back in the file with the commands
.B p
and
.B P;
\fBp\fR puts the text after or below the cursor, while \fBP\fR puts the text
before or above the cursor.
.PP
If the text which you
yank forms a part of a line, or is an object such as a sentence which
partially spans more than one line, then when you put the text back,
it will be placed after the cursor (or before if you
use \fBP\fR).  If the yanked text forms whole lines, they will be put
back as whole lines, without changing the current line.  In this case,
the put acts much like a \fBo\fR or \fBO\fR command.
.PP
Try the command \fBYP\fR.  This makes a copy of the current line and
leaves you on this copy, which is placed before the current line.
The command \fBY\fR is a convenient abbreviation for \fByy\fR.
The command \fBYp\fR will also make a copy of the current line, and place
it after the current line.  You can give \fBY\fR a count of lines to
yank, and thus duplicate several lines; try \fB3YP\fR.
.PP
To move text within the buffer, you need to delete it in one place, and
put it back in another.  You can precede a delete operation by the
name of a buffer in which the text is to be stored as in \fB"a5dd\fR
deleting 5 lines into the named buffer \fIa\fR.  You can then move the
cursor to the eventual resting place of the these lines and do a \fB"ap\fR
or \fB"aP\fR to put them back.
In fact, you can switch and edit another file before you put the lines
back, by giving a command of the form \fB:e \fR\fIname\fR\s-2CR\s0 where
\fIname\fR is the name of the other file you want to edit.  You will
have to write back the contents of the current editor buffer (or discard
them) if you have made changes before the editor will let you switch
to the other file.
An ordinary delete command saves the text in the unnamed buffer,
so that an ordinary put can move it elsewhere.
However, the unnamed buffer is lost when you change files,
so to move text from one file to another you should use an unnamed buffer.
.NH 2
Summary.
.IP
.TS
lw(.50i)b a.
\(ua	first non-white on line
$	end of line
)	forward sentence
}	forward paragraph
]]	forward section
(	backward sentence
{	backward paragraph
[[	backward section
f\fIx\fR	find \fIx\fR forward in line
p	put text back, after cursor or below current line
y	yank operator, for copies and moves
t\fIx\fR	up to \fIx\fR forward, for operators
F\fIx\fR	f backward in line
P	put text back, before cursor or above current line
T\fIx\fR	t backward in line
.TE
.NH 1
High level commands
.NH 2
Writing, quitting, editing new files
.PP
So far we have seen how to enter
.I vi
and to write out our file using either
\fBZZ\fR or \fB:w\fR\s-2CR\s0. The first exits from
the editor,
(writing if changes were made),
the second writes and stays in the editor.
.PP
If you have changed the editor's copy of the file but do not wish to
save your changes, either because you messed up the file or decided that the
changes are not an improvement to the file, then you can give the command
\fB:q!\fR\s-2CR\s0 to quit from the editor without writing the changes.
You can also reedit the same file (starting over) by giving the command
\fB:e!\fR\s-2CR\s0.  These commands should be used only rarely, and with
caution, as it is not possible to recover the changes you have made after
you discard them in this manner.