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Buffers and More Buffers
The editor vi actually works on a copy of the file in the work buffer. While
using the vi editor, one has access to other buffers as well. There are 36
buffers available to you.
- unnamed buffer
- named buffers "a, "b, "c, "d, ....., "x, "y, "z
- numbered buffers "1, "2, "3", "4, ......., "8,"9
The unnamed buffer is sometimes called the general-purpose buffer. When you
change or delete text, the old text is not discarded immediately. Instead, vi
moves the old material into the unnamed buffer, and hold the text there until
you change or delete more material. This would allow you to "undo" or restore
the text you have deleted using the "undo" command: u
This puts the old text back where it came from. Since vi has only one unnamed
buffer, the undo command can only restore the most recent change you made. The
previous changes are lost forever.
The named buffers and numbered buffers are useful for moving blocks of text
around a file or between different files.
The following scenario would move 4 lines from file named myfile5 to myfile6.
vi myfile5 myfile5
( in several lines in myfile5)
"a4yy (yank 4 lines and
place them in the buffer named a)
:n
( vi the next file)
"ap (place
the lines in the named buffer a at the current cursor position)
If you try the Put command on a buffer that has nothing in it, the computer
will respond with an error message such as
Nothing in register a
Buffers are also known as registers.
The contents of the named buffer are not changed by the Put command. One can
put the same 4 lines into the file again if so desired.
Second scenario: Moving text between files.
1. vi fileA
2. move the cursor to the first of the lines you want to trasnfer.
3. yank the lines into a named buffer named "m.
"m4yy
4. enter the edit file command. Type :e followed by the name of the file that
is to receive the yanked text. If the file is named mystuff, type
:e mystuff
5. put the lines.
"mp
6. write the lines to the file.
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