l3.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

#print
		Basic Alteration - Insert and Delete I

   So now you can move around nearly to your heart's content.  Wouldn't it
be nice if you could change something?  In the next two lessons you'll see
how to make basic changes to a file: inserting and deleting characters and
lines.  

   Inserting and deleting text are just a matter of moving to the right
place and using the right command.  We'll be looking at these six commands:

	i    a      These are the most common insertion commands.  'i' will
		    allow you to insert text before the character the cursor
		    is on and 'a' will append it after the current character.
	I    A      These are for inserting text at the beginning of the
		    current line and appending it to the end of said line.
	x    X      These are the commands for deleting characters.  'x' will
		    delete the character the cursor is on and 'X' gets rid of
		    the character before the cursor.

   Type 'ready' now to learn more about inserting and deleting.
#user
#create Insert1
   Inserting text takes four steps:
	1) Move to the proper place in the file.
	2) Type the correct insertion command (i, I, a, or A).  This puts you
	   into 'insert' mode.
	3) Enter the new text.
	4) Hit the Escape key.  This brings you back out of insert mode.

   The insertion commands, again, are as follows:
	i   inserts before the current character
	a   appends (i.e. inserts after the current character)
	I   inserts before the beginning of the current line
	A   appends text after the end of the current line

   Try inserting some text now anywhere in the file.  Don't touch anything past
the dashed line, though.

   Deleting text is merely a matter of moving the cursor to the characters to
be deleted and hitting x once per character.  They should disappear.  You can
also use the X command, which deletes the character right before the current
one.  This doesn't appear to get used too frequently, however.  Try deleting 
some text now, anywhere in the file.  Still don't touch things after the dashed
line, though.  When you're done, do the exercise below.
--------------------------------------------------------------------------
EXERCISE 
	Delete the words 'blort' and 'gronk' below.  Don't delete the
dashes or equals signs.  Then insert the word 'blather' between the equals
signs.  Be sure to save your changes before you leave the editor.

		-blort==gronk-
#create Answer
		-=blather=-
#
vi Insert1
grep =- Insert1 > Attempt
#cmp Attempt Answer
#succeed
Not bad... Not bad at all.  It looks like you pick up this stuff pretty
quickly.
#fail

Accidents will happen.  Give it another try.  This time spend a little more
time practicing before you do the exercise.  If you managed to do it but
couldn't remember how to save the file, try it again anyway.  You save your
work by using the :w command.

Type 'ready' when the learn program types a percent sign.
#next
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