VIP

VIP is a Vi emulating package written in Emacs Lisp. VIP implements most Vi commands including Ex commands. It is therefore hoped that this package will enable you to do Vi style editing under the powerful GNU Emacs environment. This info file describes the usage of VIP assuming that you are fairly accustomed to Vi but not so much with Emacs. Also we will concentrate mainly on differences from Vi, especially features unique to VIP.

It is recommended that you read nodes on survey and on customization before you start using VIP. Other nodes may be visited as needed.

Comments and bug reports are welcome. Please send messages to ms@Sail.Stanford.Edu if you are outside of Japan and to masahiko@sato.riec.tohoku.junet if you are in Japan.

Copyright © 1987, 2001–2013 Free Software Foundation, Inc.

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with the Front-Cover texts being “A GNU Manual”, and with the Back-Cover Texts as in (a) below. A copy of the license is included in the section entitled “GNU Free Documentation License”.

(a) The FSF's Back-Cover Text is: “You have the freedom to copy and modify this GNU manual.”

Survey A survey of VIP.
Vi Commands Details of Vi commands.
Ex Commands Details of Ex commands.
Customization How to customize VIP.
GNU Free Documentation License The license for this documentation.

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1 A Survey of VIP

In this chapter we describe basics of VIP with emphasis on the features not found in Vi and on how to use VIP under GNU Emacs.

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1.1 Basic Concepts

We begin by explaining some basic concepts of Emacs. These concepts are explained in more detail in the GNU Emacs Manual.

Conceptually, a buffer is just a string of ASCII characters and two special characters <PNT> (point) and <MRK> (mark) such that the character <PNT> occurs exactly once and <MRK> occurs at most once. The text of a buffer is obtained by deleting the occurrences of <PNT> and <MRK>. If, in a buffer, there is a character following <PNT> then we say that point is looking at the character; otherwise we say that point is at the end of buffer. <PNT> and <MRK> are used to indicate positions in a buffer and they are not part of the text of the buffer. If a buffer contains a <MRK> then the text between <MRK> and <PNT> is called the region of the buffer.

Emacs provides (multiple) windows on the screen, and you can see the content of a buffer through the window associated with the buffer. The cursor of the screen is always positioned on the character after <PNT>.

A keymap is a table that records the bindings between characters and command functions. There is the global keymap common to all the buffers. Each buffer has its local keymap that determines the mode of the buffer. Local keymap overrides global keymap, so that if a function is bound to some key in the local keymap then that function will be executed when you type the key. If no function is bound to a key in the local map, however, the function bound to the key in the global map becomes in effect.

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1.2 Loading VIP

The recommended way to load VIP automatically is to include the line:

     (load "vip")

in your .emacs file. The .emacs file is placed in your home directory and it will be executed every time you invoke Emacs. If you wish to be in vi mode whenever Emacs starts up, you can include the following line in your .emacs file instead of the above line:

     (setq term-setup-hook 'vip-mode)

(See Vi Mode, for the explanation of vi mode.)

Even if your .emacs file does not contain any of the above lines, you can load VIP and enter vi mode by typing the following from within Emacs.

     M-x vip-mode

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1.3 Modes in VIP

Loading VIP has the effect of globally binding C-z (Control-z) to the function vip-change-mode-to-vi. The default binding of C-z in GNU Emacs is suspend-emacs, but, you can also call suspend-emacs by typing C-x C-z. Other than this, all the key bindings of Emacs remain the same after loading VIP.

Now, if you hit C-z, the function vip-change-mode-to-vi will be called and you will be in vi mode. (Some major modes may locally bind C-z to some special functions. In such cases, you can call vip-change-mode-to-vi by execute-extended-command which is invoked by M-x. Here M-x means Meta-x, and if your terminal does not have a <META> key you can enter it by typing <ESC> x. The same effect can also be achieve by typing M-x vip-mode.)

You can observe the change of mode by looking at the mode line. For instance, if the mode line is:

     -----Emacs: *scratch*              (Lisp Interaction)----All------------

then it will change to:

     -----Vi:    *scratch*              (Lisp Interaction)----All------------

Thus the word ‘Emacs’ in the mode line will change to ‘Vi’.

You can go back to the original emacs mode by typing C-z in vi mode. Thus C-z toggles between these two modes.

Note that modes in VIP exist orthogonally to modes in Emacs. This means that you can be in vi mode and at the same time, say, shell mode.

Vi mode corresponds to Vi's command mode. From vi mode you can enter insert mode (which corresponds to Vi's insert mode) by usual Vi command keys like i, a, o ... etc.

In insert mode, the mode line will look like this:

     -----Insert *scratch*              (Lisp Interaction)----All------------

You can exit from insert mode by hitting <ESC> key as you do in Vi.

That VIP has three modes may seem very complicated, but in fact it is not so. VIP is implemented so that you can do most editing remaining only in the two modes for Vi (that is vi mode and insert mode).

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1.3.1 Emacs Mode

You will be in this mode just after you loaded VIP. You can do all normal Emacs editing in this mode. Note that the key C-z is globally bound to vip-change-mode-to-vi. So, if you type C-z in this mode then you will be in vi mode.

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1.3.2 Vi Mode

This mode corresponds to Vi's command mode. Most Vi commands work as they do in Vi. You can go back to emacs mode by typing C-z. You can enter insert mode, just as in Vi, by typing i, a etc.

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1.3.3 Insert Mode

The key bindings in this mode is the same as in the emacs mode except for the following 4 keys. So, you can move around in the buffer and change its content while you are in insert mode.

<ESC>
This key will take you back to vi mode.
C-h
Delete previous character.
C-w
Delete previous word.
C-z
Typing this key has the same effect as typing <ESC> in emacs mode. Thus typing C-z x in insert mode will have the same effect as typing ESC x in emacs mode.

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1.4 Differences from Vi

The major differences from Vi are explained below.

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1.4.1 Undoing

You can repeat undoing by the . key. So, u will undo a single change, while u . . ., for instance, will undo 4 previous changes. Undo is undoable as in Vi. So the content of the buffer will be the same before and after u u.

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1.4.2 Changing

Some commands which change a small number of characters are executed slightly differently. Thus, if point is at the beginning of a word ‘foo’ and you wished to change it to ‘bar’ by typing c w, then VIP will prompt you for a new word in the minibuffer by the prompt ‘foo => ’. You can then enter ‘bar’ followed by <RET> or <ESC> to complete the command. Before you enter <RET> or <ESC> you can abort the command by typing C-g. In general, you can abort a partially formed command by typing C-g.

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1.4.3 Searching

As in Vi, searching is done by / and ?. The string will be searched literally by default. To invoke a regular expression search, first execute the search command / (or ?) with empty search string. (I.e., type / followed by <RET>.) A search for empty string will toggle the search mode between vanilla search and regular expression search. You cannot give an offset to the search string. (It is a limitation.) By default, search will wrap around the buffer as in Vi. You can change this by rebinding the variable vip-search-wrap-around. See Customization, for how to do this.

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1.4.4 z Command

For those of you who cannot remember which of z followed by <RET>, . and - do what. You can also use z followed by H, M and L to place the current line in the Home (Middle, and Last) line of the window.

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1.4.5 Counts

Some Vi commands which do not accept a count now accept one

p
P
Given counts, text will be yanked (in Vi's sense) that many times. Thus 3 p is the same as p p p.
o
O
Given counts, that many copies of text will be inserted. Thus o a b c <ESC> will insert 3 lines of ‘abc’ below the current line.
/
?
Given a count n, n-th occurrence will be searched.

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1.4.6 Marking

Typing an m followed by a lower-case character ch marks the point to the register named ch as in Vi. In addition to these, we have following key bindings for marking.

m <
Set mark at the beginning of buffer.
m >
Set mark at the end of buffer.
m .
Set mark at point (and push old mark on mark ring).
m ,
Jump to mark (and pop mark off the mark ring).

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1.4.7 Region Commands

Vi operators like d, c etc. are usually used in combination with motion commands. It is now possible to use current region as the argument to these operators. (A region is a part of buffer delimited by point and mark.) The key r is used for this purpose. Thus d r will delete the current region. If R is used instead of r the region will first be enlarged so that it will become the smallest region containing the original region and consisting of whole lines. Thus m . d R will have the same effect as d d.

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1.4.8 Some New Commands

Note that the keys below (except for R) are not used in Vi.

C-a
Move point to the beginning of line.
C-n
If you have two or more windows in the screen, this key will move point to the next window.
C-o
Insert a newline and leave point before it, and then enter insert mode.
C-r
Backward incremental search.
C-s
Forward incremental search.
C-c
C-x
<ESC>
These keys will exit from vi mode and return to emacs mode temporarily. If you hit one of these keys, Emacs will be in emacs mode and will believe that you hit that key in emacs mode. For example, if you hit C-x followed by 2, then the current window will be split into 2 and you will be in vi mode again.
\
Escape to emacs mode. Hitting \ will take you to emacs mode, and you can execute a single Emacs command. After executing the Emacs command you will be in vi mode again. You can give a count before typing \. Thus 5 \ *, as well as \ C-u 5 *, will insert ‘*****’ before point. Similarly 1 0 \ C-p will move the point 10 lines above the current line.
K
Kill current buffer if it is not modified. Useful when you selected a buffer which you did not want.
Q
R
Q is for query replace and R is for replace. By default, string to be replaced are treated literally. If you wish to do a regular expression replace, first do replace with empty string as the string to be replaced. In this way, you can toggle between vanilla and regular expression replacement.
v
V
These keys are used to Visit files. v will switch to a buffer visiting file whose name can be entered in the minibuffer. V is similar, but will use window different from the current window.
#
If followed by a certain character ch, it becomes an operator whose argument is the region determined by the motion command that follows. Currently, ch can be one of c, C, g, q and s.
# c
Change upper-case characters in the region to lower case (downcase-region).
# C
Change lower-case characters in the region to upper case. For instance, # C 3 w will capitalize 3 words from the current point (upcase-region).
# g
Execute last keyboard macro for each line in the region (vip-global-execute).
# q
Insert specified string at the beginning of each line in the region (vip-quote-region).
# s
Check spelling of words in the region (spell-region).
*
Call last keyboard macro.

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1.4.9 New Key Bindings

In VIP the meanings of some keys are entirely different from Vi. These key bindings are done deliberately in the hope that editing under Emacs will become easier. It is however possible to rebind these keys to functions which behave similarly as in Vi. See Customizing Key Bindings, for details.

C-g
g
In Vi, C-g is used to get information about the file associated to the current buffer. Here, g will do that, and C-g is used to abort a command (this is for compatibility with emacs mode.)
SPC
<RET>
Now these keys will scroll up and down the text of current window. Convenient for viewing the text.
s
S
They are used to switch to a specified buffer. Useful for switching to already existing buffer since buffer name completion is provided. Also a default buffer will be given as part of the prompt, to which you can switch by just typing <RET> key. s is used to select buffer in the current window, while S selects buffer in another window.
C
X
These keys will exit from vi mode and return to emacs mode temporarily. If you type C (X), Emacs will be in emacs mode and will believe that you have typed C-c (C-x, resp.) in emacs mode. Moreover, if the following character you type is an upper-case letter, then Emacs will believe that you have typed the corresponding control character. You will be in vi mode again after the command is executed. For example, typing X S in vi mode is the same as typing C-x C-s in emacs mode. You get the same effect by typing C-x C-s in vi mode, but the idea here is that you can execute useful Emacs commands without typing control characters. For example, if you hit X (or C-x) followed by 2, then the current window will be split into 2 and you will be in vi mode again.

In addition to these, ctl-x-map is slightly modified:

X 3
C-x 3
This is equivalent to C-x 1 C-x 2 (1 + 2 = 3).

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1.4.10 Window Commands

In this and following subsections, we give a summary of key bindings for basic functions related to windows, buffers and files.

C-n
Switch to next window.
X 1
C-x 1
Delete other windows.
X 2
C-x 2
Split current window into two windows.
X 3
C-x 3
Show current buffer in two windows.

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1.4.11 Buffer Commands

s
Switch to the specified buffer in the current window (vip-switch-to-buffer).
S
Switch to the specified buffer in another window (vip-switch-to-buffer-other-window).
K
Kill the current buffer if it is not modified.
X S
C-x C-s
Save the current buffer in the file associated to the buffer.

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1.4.12 File Commands

v
Visit specified file in the current window.
V
Visit specified file in another window.
X W
C-x C-w
Write current buffer into the specified file.
X I
C-x C-i
Insert specified file at point.

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1.4.13 Miscellaneous Commands

X (
C-x (
Start remembering keyboard macro.
X )
C-x )
Finish remembering keyboard macro.
*
Call last remembered keyboard macro.
X Z
C-x C-z
Suspend Emacs.
Z Z
Exit Emacs.
Q
Query replace.
R
Replace.

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2 Vi Commands

This chapter describes Vi commands other than Ex commands implemented in VIP. Except for the last section which discusses insert mode, all the commands described in this chapter are to be used in vi mode.

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2.1 Numeric Arguments

Most Vi commands accept a numeric argument which can be supplied as a prefix to the commands. A numeric argument is also called a count. In many cases, if a count is given, the command is executed that many times. For instance, 5 d d deletes 5 lines while simple d d deletes a line. In this manual the metavariable n will denote a count.

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2.2 Important Keys

The keys C-g and C-l are unique in that their associated functions are the same in any of emacs, vi and insert mode.

C-g
Quit. Cancel running or partially typed command (keyboard-quit).
C-l
Clear the screen and reprint everything (recenter).

In Emacs many commands are bound to the key strokes that start with C-x, C-c and <ESC>. These commands can be accessed from vi mode as easily as from emacs mode.

C-x
C-c
<ESC>
Typing one of these keys have the same effect as typing it in emacs mode. Appropriate command will be executed according as the keys you type after it. You will be in vi mode again after the execution of the command. For instance, if you type <ESC> < (in vi mode) then the cursor will move to the beginning of the buffer and you will still be in vi mode.
C
X
Typing one of these keys have the effect of typing the corresponding control character in emacs mode. Moreover, if you type an upper-case character following it, that character will also be translated to the corresponding control character. Thus typing X W in vi mode is the same as typing C-x C-w in emacs mode. You will be in vi mode again after the execution of a command.
\
Escape to emacs mode. Hitting the \ key will take you to emacs mode, and you can execute a single Emacs command. After executing the Emacs command you will be in vi mode again. You can give a count before typing \. Thus 5 \ +, as well as \ C-u 5 +, will insert ‘+++++’ before point.

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2.3 Buffers and Windows

In Emacs the text you edit is stored in a buffer. See GNU Emacs Manual, for details. There is always one current buffer, also called the selected buffer.

You can see the contents of buffers through windows created by Emacs. When you have multiple windows on the screen only one of them is selected. Each buffer has a unique name, and each window has a mode line which shows the name of the buffer associated with the window and other information about the status of the buffer. You can change the format of the mode line, but normally if you see ‘**’ at the beginning of a mode line it means that the buffer is modified. If you write out the content of the buffer to a file, then the buffer will become not modified. Also if you see ‘%%’ at the beginning of the mode line, it means that the file associated with the buffer is write protected.

We have the following commands related to windows and buffers.

C-n
Move cursor to the next-window (vip-next-window).
X 1
Delete other windows and make the selected window fill the screen
(delete-other-windows).
X 2
Split current window into two windows (split-window-vertically).
X 3
Show current buffer in two windows.
s buffer <RET>
Select or create a buffer named buffer (vip-switch-to-buffer).
S buffer <RET>
Similar but select a buffer named buffer in another window
(vip-switch-to-buffer-other-window).
K
Kill the current buffer if it is not modified or if it is not associated with a file
(vip-kill-buffer).
X B
List the existing buffers (list-buffers).

As buffer name completion is provided, you have only to type in initial substring of the buffer name which is sufficient to identify it among names of existing buffers. After that, if you hit <TAB> the rest of the buffer name will be supplied by the system, and you can confirm it by <RET>. The default buffer name to switch to will also be prompted, and you can select it by giving a simple <RET>. See GNU Emacs Manual for details of completion.

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2.4 Files

We have the following commands related to files. They are used to visit, save and insert files.

v file <RET>
Visit specified file in the current window (vip-find-file).
V file <RET>
Visit specified file in another window (vip-find-file-other-window).
X S
Save current buffer to the file associated with the buffer. If no file is associated with the buffer, the name of the file to write out the content of the buffer will be asked in the minibuffer.
X W file <RET>
Write current buffer into a specified file.
X I file <RET>
Insert a specified file at point.
g
Give information on the file associated with the current buffer. Tell you the name of the file associated with the buffer, the line number of the current point and total line numbers in the buffer. If no file is associated with the buffer, this fact will be indicated by the null file name ‘""’.

In Emacs, you can edit a file by visiting it. If you wish to visit a file in the current window, you can just type v. Emacs maintains the default directory which is specific to each buffer. Suppose, for instance, that the default directory of the current buffer is /usr/masahiko/lisp/. Then you will get the following prompt in the minibuffer.

     visit file: /usr/masahiko/lisp/

If you wish to visit, say, vip.el in this directory, then you can just type ‘vip.el’ followed by <RET>. If the file vip.el already exists in the directory, Emacs will visit that file, and if not, the file will be created. Emacs will use the file name (vip.el, in this case) as the name of the buffer visiting the file. In order to make the buffer name unique, Emacs may append ‘<2>’, ‘<3>’ etc., to the buffer name. As the file name completion is provided here, you can sometime save typing. For instance, suppose there is only one file in the default directory whose name starts with ‘v’, that is ‘vip.el’. Then if you just type v <TAB> then it will be completed to ‘vip.el’. Thus, in this case, you just have to type v v <TAB> <RET> to visit /usr/masahiko/lisp/vip.el. Continuing the example, let us now suppose that you wished to visit the file /usr/masahiko/man/vip.texinfo. Then to the same prompt which you get after you typed v, you can enter ‘/usr/masahiko/man/vip.texinfo’ or ‘../man/vip.texinfo’ followed by <RET>.

Use V instead of v, if you wish to visit a file in another window.

You can verify which file you are editing by typing g. (You can also type X B to get information on other buffers too.) If you type g you will get an information like below in the echo area:

     "/usr/masahiko/man/vip.texinfo" line 921 of 1949

After you edited the buffer (‘vip.texinfo’, in our example) for a while, you may wish to save it in a file. If you wish to save it in the file associated with the buffer (/usr/masahiko/man/vip.texinfo, in this case), you can just say X S. If you wish to save it in another file, you can type X W. You will then get a similar prompt as you get for v, to which you can enter the file name.

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2.5 Viewing the Buffer

In this and next section we discuss commands for moving around in the buffer. These command do not change the content of the buffer. The following commands are useful for viewing the content of the current buffer.

<SPC>
C-f
Scroll text of current window upward almost full screen. You can go forward in the buffer by this command (vip-scroll).
<RET>
C-b
Scroll text of current window downward almost full screen. You can go backward in the buffer by this command (vip-scroll-back).
C-d
Scroll text of current window upward half screen. You can go down in the buffer by this command (vip-scroll-down).
C-u
Scroll text of current window downward half screen. You can go up in the buffer by this command (vip-scroll-up).
C-y
Scroll text of current window upward by one line (vip-scroll-down-one).
C-e
Scroll text of current window downward by one line (vip-scroll-up-one).
You can repeat these commands by giving a count. Thus, 2 <SPC> has the same effect as <SPC> <SPC>.

The following commands reposition point in the window.

z H
z <RET>
Put point on the top (home) line in the window. So the current line becomes the top line in the window. Given a count n, point will be placed in the n-th line from top (vip-line-to-top).
z M
z .
Put point on the middle line in the window. Given a count n, point will be placed in the n-th line from the middle line (vip-line-to-middle).
z L
z -
Put point on the bottom line in the window. Given a count n, point will be placed in the n-th line from bottom (vip-line-to-bottom).
C-l
Center point in window and redisplay screen (recenter).

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2.6 Mark Commands

The following commands are used to mark positions in the buffer.

m ch
Store current point in the register ch. ch must be a lower-case ASCII letter.
m <
Set mark at the beginning of current buffer.
m >
Set mark at the end of current buffer.
m .
Set mark at point.
m ,
Jump to mark (and pop mark off the mark ring).

Emacs uses the mark ring to store marked positions. The commands m <, m > and m . not only set mark but also add it as the latest element of the mark ring (replacing the oldest one). By repeating the command `m ,' you can visit older and older marked positions. You will eventually be in a loop as the mark ring is a ring.

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2.7 Motion Commands

Commands for moving around in the current buffer are collected here. These commands are used as an `argument' for the delete, change and yank commands to be described in the next section.

h
Move point backward by one character. Signal error if point is at the beginning of buffer, but (unlike Vi) do not complain otherwise (vip-backward-char).
l
Move point backward by one character. Signal error if point is at the end of buffer, but (unlike Vi) do not complain otherwise (vip-forward-char).
j
Move point to the next line keeping the current column. If point is on the last line of the buffer, a new line will be created and point will move to that line (vip-next-line).
k
Move point to the previous line keeping the current column (vip-next-line).
+
Move point to the next line at the first non-white character. If point is on the last line of the buffer, a new line will be created and point will move to the beginning of that line (vip-next-line-at-bol).
-
Move point to the previous line at the first non-white character (vip-previous-line-at-bol).
If a count is given to these commands, the commands will be repeated that many times.
0
Move point to the beginning of line (vip-beginning-of-line).
^
Move point to the first non-white character on the line (vip-bol-and-skip-white).
$
Move point to the end of line (vip-goto-eol).
n |
Move point to the n-th column on the line (vip-goto-col).
Except for the | command, these commands neglect a count.

w
Move point forward to the beginning of the next word (vip-forward-word).
W
Move point forward to the beginning of the next word, where a word is considered as a sequence of non-white characters (vip-forward-Word).
b
Move point backward to the beginning of a word (vip-backward-word).
B
Move point backward to the beginning of a word, where a word is considered as a sequence of non-white characters (vip-forward-Word).
e
Move point forward to the end of a word (vip-end-of-word).
E
Move point forward to the end of a word, where a word is considered as a sequence of non-white characters (vip-end-of-Word).
Here the meaning of the word `word' for the w, b and e commands is determined by the syntax table effective in the current buffer. Each major mode has its syntax mode, and therefore the meaning of a word also changes as the major mode changes. See GNU Emacs Manual for details of syntax table.
H
Move point to the beginning of the home (top) line of the window. Given a count n, go to the n-th line from top (vip-window-top).
M
Move point to the beginning of the middle line of the window. Given a count n, go to the n-th line from the middle line (vip-window-middle).
L
Move point to the beginning of the lowest (bottom) line of the window. Given count, go to the n-th line from bottom (vip-window-bottom).
These commands can be used to go to the desired line visible on the screen.
(
Move point backward to the beginning of the sentence (vip-backward-sentence).
)
Move point forward to the end of the sentence (vip-forward-sentence).
{
Move point backward to the beginning of the paragraph (vip-backward-paragraph).
}
Move point forward to the end of the paragraph (vip-forward-paragraph).
A count repeats the effect for these commands.
G
Given a count n, move point to the n-th line in the buffer on the first non-white character. Without a count, go to the end of the buffer (vip-goto-line).
` `
Exchange point and mark (vip-goto-mark).
` ch
Move point to the position stored in the register ch. ch must be a lower-case letter.
' '
Exchange point and mark, and then move point to the first non-white character on the line (vip-goto-mark-and-skip-white).
' ch
Move point to the position stored in the register ch and skip to the first non-white character on the line. ch must be a lower-case letter.
%
Move point to the matching parenthesis if point is looking at (, ), {, }, [ or ]
(vip-paren-match).
The command G mark point before move, so that you can return to the original point by ` `. The original point will also be stored in the mark ring.

The following commands are useful for moving points on the line. A count will repeat the effect.

f ch
Move point forward to the character ch on the line. Signal error if ch could not be found (vip-find-char-forward).
F ch
Move point backward to the character ch on the line. Signal error if ch could not be found (vip-find-char-backward).
t ch
Move point forward upto the character ch on the line. Signal error if ch could not be found (vip-goto-char-forward).
T ch
Move point backward upto the character ch on the line. Signal error if ch could not be found (vip-goto-char-backward).
;
Repeat previous f, t, F or T command (vip-repeat-find).
,
Repeat previous f, t, F or T command, in the opposite direction (vip-repeat-find-opposite).

Next: , Previous: Motion Commands, Up: Vi Commands

2.8 Searching and Replacing

Following commands are available for searching and replacing.

/ string <RET>
Search the first occurrence of the string string forward starting from point. Given a count n, the n-th occurrence of string will be searched. If the variable vip-re-search has value t then regular expression search is done and the string matching the regular expression string is found. If you give an empty string as string then the search mode will change from vanilla search to regular expression search and vice versa (vip-search-forward).
? string <RET>
Same as /, except that search is done backward (vip-search-backward).
n
Search the previous search pattern in the same direction as before (vip-search-next).
N
Search the previous search pattern in the opposite direction (vip-search-Next).
C-s
Search forward incrementally. See GNU Emacs Manual for details (isearch-forward).
C-r
Search backward incrementally (isearch-backward).
R string RET newstring
There are two modes of replacement, vanilla and regular expression. If the mode is vanilla you will get a prompt ‘Replace string:’, and if the mode is regular expression you will ge a prompt ‘Replace regexp:’. The mode is initially vanilla, but you can toggle these modes by giving a null string as string. If the mode is vanilla, this command replaces every occurrence of string with newstring. If the mode is regular expression, string is treated as a regular expression and every string matching the regular expression is replaced with newstring (vip-replace-string).
Q string RET newstring
Same as R except that you will be asked form confirmation before each replacement
(vip-query-replace).
r ch
Replace the character point is looking at by the character ch. Give count, replace that many characters by ch (vip-replace-char).
The commands / and ? mark point before move, so that you can return to the original point by ` `.

Next: , Previous: Searching and Replacing, Up: Vi Commands

2.9 Modifying Commands

In this section, commands for modifying the content of a buffer are described. These commands affect the region determined by a motion command which is given to the commands as their argument.

We classify motion commands into point commands and line commands. The point commands are as follows:

     h, l, 0, ^, $, w, W, b, B, e, E, (, ), /, ?, `, f, F, t, T, %, ;, ,

The line commands are as follows:

     j, k, +, -, H, M, L, {, }, G, '

If a point command is given as an argument to a modifying command, the region determined by the point command will be affected by the modifying command. On the other hand, if a line command is given as an argument to a modifying command, the region determined by the line command will be enlarged so that it will become the smallest region properly containing the region and consisting of whole lines (we call this process expanding the region), and then the enlarged region will be affected by the modifying command.

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2.9.1 Delete Commands

d motion-command
Delete the region determined by the motion command motion-command.
For example, d $ will delete the region between point and end of current line since $ is a point command that moves point to end of line. d G will delete the region between the beginning of current line and end of the buffer, since G is a line command. A count given to the command above will become the count for the associated motion command. Thus, 3 d w will delete three words.

It is also possible to save the deleted text into a register you specify. For example, you can say " t 3 d w to delete three words and save it to register t. The name of a register is a lower-case letter between a and z. If you give an upper-case letter as an argument to a delete command, then the deleted text will be appended to the content of the register having the corresponding lower-case letter as its name. So, " T d w will delete a word and append it to register t. Other modifying commands also accept a register name as their argument, and we will not repeat similar explanations.

We have more delete commands as below.

d d
Delete a line. Given a count n, delete n lines.
d r
Delete current region.
d R
Expand current region and delete it.
D
Delete to the end of a line (vip-kill-line).
x
Delete a character after point. Given n, delete n characters (vip-delete-char).
<DEL>
Delete a character before point. Given n, delete n characters (vip-delete-backward-char).

Next: , Previous: Delete Commands, Up: Modifying Commands

2.9.2 Yank Commands

Yank commands yank a text of buffer into a (usually anonymous) register. Here the word `yank' is used in Vi's sense. Thus yank commands do not alter the content of the buffer, and useful only in combination with commands that put back the yanked text into the buffer.

y motion-command
Yank the region determined by the motion command motion-command.
For example, y $ will yank the text between point and the end of line into an anonymous register, while "c y $ will yank the same text into register c.

Use the following command to yank consecutive lines of text.

y y
Y
Yank a line. Given n, yank n lines (vip-yank-line).
y r
Yank current region.
y R
Expand current region and yank it.

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2.9.3 Put Back Commands

Deleted or yanked texts can be put back into the buffer by the command below.

p
Insert, after the character point is looking at, most recently deleted/yanked text from anonymous register. Given a register name argument, the content of the named register will be put back. Given a count, the command will be repeated that many times. This command also checks if the text to put back ends with a new line character, and if so the text will be put below the current line (vip-put-back).
P
Insert at point most recently deleted/yanked text from anonymous register. Given a register name argument, the content of the named register will be put back. Given a count, the command will be repeated that many times. This command also checks if the text to put back ends with a new line character, and if so the text will be put above the current line rather than at point (vip-Put-back).
Thus, " c p will put back the content of the register c into the buffer. It is also possible to specify number register which is a numeral between 1 and 9. If the number register n is specified, n-th previously deleted/yanked text will be put back. It is an error to specify a number register for the delete/yank commands.

Next: , Previous: Put Back Commands, Up: Modifying Commands

2.9.4 Change Commands

Most commonly used change command takes the following form.

c motion-command
Replace the content of the region determined by the motion command motion-command by the text you type. If the motion command is a point command then you will type the text into minibuffer, and if the motion command is a line command then the region will be deleted first and you can insert the text in insert mode.
For example, if point is at the beginning of a word ‘foo’ and you wish to change it to ‘bar’, you can type c w. Then, as w is a point command, you will get the prompt ‘foo =>’ in the minibuffer, for which you can type b a r <RET> to complete the change command.
c c
Change a line. Given a count, that many lines are changed.
c r
Change current region.
c R
Expand current region and change it.

Next: , Previous: Change Commands, Up: Modifying Commands

2.9.5 Repeating and Undoing Modifications

VIP records the previous modifying command, so that it is easy to repeat it. It is also very easy to undo changes made by modifying commands.

u
Undo the last change. You can undo more by repeating undo by the repeat command ‘.’. For example, you can undo 5 previous changes by typing ‘u....’. If you type ‘uu’, then the second ‘u’ undoes the first undo command (vip-undo).
.
Repeat the last modifying command. Given count n it becomes the new count for the repeated command. Otherwise, the count for the last modifying command is used again (vip-repeat).

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2.10 Other Vi Commands

Miscellaneous Vi commands are collected here.

Z Z
Exit Emacs. If modified buffers exist, you will be asked whether you wish to save them or not (save-buffers-kill-emacs).
! motion-command format-command
n ! ! format-command
The region determined by the motion command motion-command will be given to the shell command format-command and the region will be replaced by its output. If a count is given, it will be passed to motion-command. For example, ‘3!Gsort’ will sort the region between point and the 3rd line. If ! is used instead of motion-command then n lines will be processed by format-command (vip-command-argument).
J
Join two lines. Given count, join that many lines. A space will be inserted at each junction (vip-join-lines).
< motion-command
n < <
Shift region determined by the motion command motion-command to left by shift-width (default is 8). If < is used instead of motion-command then shift n lines
(vip-command-argument).
> motion-command
n > >
Shift region determined by the motion command motion-command to right by shift-width (default is 8). If < is used instead of motion-command then shift n lines
(vip-command-argument).
= motion-command
Indent region determined by the motion command motion-command. If = is used instead of motion-command then indent n lines (vip-command-argument).
*
Call last remembered keyboard macro.
#
A new vi operator. See New Commands, for more details.

The following keys are reserved for future extensions, and currently assigned to a function that just beeps (vip-nil).

     &, @, U, [, ], _, q, ~

VIP uses a special local keymap to interpret key strokes you enter in vi mode. The following keys are bound to nil in the keymap. Therefore, these keys are interpreted by the global keymap of Emacs. We give below a short description of the functions bound to these keys in the global keymap. See GNU Emacs Manual for details.

C-@
Set mark and push previous mark on mark ring (set-mark-command).
TAB
Indent line for current major mode (indent-for-tab-command).
C-j
Insert a newline, then indent according to mode (newline-and-indent).
C-k
Kill the rest of the current line; before a newline, kill the newline. With a numeric argument, kill that many lines from point. Negative arguments kill lines backward (kill-line).
C-l
Clear the screen and reprint everything (recenter).
n C-p
Move cursor vertically up n lines (previous-line).
C-q
Read next input character and insert it. Useful for inserting control characters
(quoted-insert).
C-r
Search backward incrementally (isearch-backward).
C-s
Search forward incrementally (isearch-forward).
n C-t
Interchange characters around point, moving forward one character. With count n, take character before point and drag it forward past n other characters. If no argument and at end of line, the previous two characters are exchanged (transpose-chars).
n C-v
Scroll text upward n lines. If n is not given, scroll near full screen (scroll-up).
C-w
Kill between point and mark. The text is save in the kill ring. The command P or p can retrieve it from kill ring (kill-region).

Next: , Previous: Other Vi Commands, Up: Vi Commands

2.11 Insert Mode

You can enter insert mode by one of the following commands. In addition to these, you will enter insert mode if you give a change command with a line command as the motion command. Insert commands are also modifying commands and you can repeat them by the repeat command . (vip-repeat).

i
Enter insert mode at point (vip-insert).
I
Enter insert mode at the first non white character on the line (vip-Insert).
a
Move point forward by one character and then enter insert mode (vip-append).
A
Enter insert mode at end of line (vip-Append).
o
Open a new line below the current line and enter insert mode (vip-open-line).
O
Open a new line above the current line and enter insert mode (vip-Open-line).
C-o
Insert a newline and leave point before it, and then enter insert mode
(vip-open-line-at-point).

Insert mode is almost like emacs mode. Only the following 4 keys behave differently from emacs mode.

<ESC>
This key will take you back to vi mode (vip-change-mode-to-vi).
C-h
Delete previous character (delete-backward-char).
C-w
Delete previous word (vip-delete-backward-word).
C-z
This key simulates <ESC> key in emacs mode. For instance, typing C-z x in insert mode is the same as typing ESC x in emacs mode (vip-ESC).
You can also bind C-h to help-command if you like. (See Customizing Key Bindings, for details.) Binding C-h to help-command has the effect of making the meaning of C-h uniform among emacs, vi and insert modes.

When you enter insert mode, VIP records point as the start point of insertion, and when you leave insert mode the region between point and start point is saved for later use by repeat command etc. Therefore, repeat command will not really repeat insertion if you move point by emacs commands while in insert mode.

Next: , Previous: Commands in Insert Mode, Up: Top

3 Ex Commands

In vi mode, you can execute an Ex command ex-command by typing:

     : ex-command <RET>

Every Ex command follows the following pattern:

     address command ! parameters count flags

where all parts are optional. For the syntax of address, the reader is referred to the reference manual of Ex.

In the current version of VIP, searching by Ex commands is always magic. That is, search patterns are always treated as regular expressions. For example, a typical forward search would be invoked by :/pat/. If you wish to include ‘/’ as part of pat you must preceded it by ‘\’. VIP strips off these \'s before / and the resulting pat becomes the actual search pattern. Emacs provides a different and richer class or regular expressions than Vi/Ex, and VIP uses Emacs's regular expressions. See GNU Emacs Manual for details of regular expressions.

Several Ex commands can be entered in a line by separating them by a pipe character ‘|’.

Next: , Previous: Ex Commands, Up: Ex Commands

3.1 Ex Command Reference

In this section we briefly explain all the Ex commands supported by VIP. Most Ex commands expect address as their argument, and they use default addresses if they are not explicitly given. In the following, such default addresses will be shown in parentheses.

Most command names can and preferably be given in abbreviated forms. In the following, optional parts of command names will be enclosed in brackets. For example, ‘co[py]’ will mean that copy command can be give as ‘co’ or ‘cop’ or ‘copy’.

If command is empty, point will move to the beginning of the line specified by the address. If address is also empty, point will move to the beginning of the current line.

Some commands accept flags which are one of p, l and #. If flags are given, the text affected by the commands will be displayed on a temporary window, and you will be asked to hit return to continue. In this way, you can see the text affected by the commands before the commands will be executed. If you hit C-g instead of <RET> then the commands will be aborted. Note that the meaning of flags is different in VIP from that in Vi/Ex.

(.,.) co[py] addr flags
(.,.) t addr flags
Place a copy of specified lines after addr. If addr is 0, it will be placed before the first line.
(.,.) d[elete] register count flags
Delete specified lines. Text will be saved in a named register if a lower-case letter is given, and appended to a register if a capital letter is given.
e[dit] ! +addr file
e[x] ! +addr file
vi[sual] ! +addr file
Edit a new file file in the current window. The command will abort if current buffer is modified, which you can override by giving !. If +addr is given, addr becomes the current line.
file
Give information about the current file.
(1,$) g[lobal] ! /pat/ cmds
(1,$) v /pat/ cmds
Among specified lines first mark each line which matches the regular expression pat, and then execute cmds on each marked line. If ! is given, cmds will be executed on each line not matching pat. v is same as g!.
(.,.+1) j[oin] ! count flags
Join specified lines into a line. Without !, a space character will be inserted at each junction.
(.) k ch
(.) mar[k] ch
Mark specified line by a lower-case character ch. Then the addressing form 'ch will refer to this line. No white space is required between k and ch. A white space is necessary between mark and ch, however.
map ch rhs
Define a macro for vi mode. After this command, the character ch will be expanded to rhs in vi mode.
(.,.) m[ove] addr
Move specified lines after addr.
(.) pu[t] register
Put back previously deleted or yanked text. If register is given, the text saved in the register will be put back; otherwise, last deleted or yanked text will be put back.
q[uit] !
Quit from Emacs. If modified buffers with associated files exist, you will be asked whether you wish to save each of them. At this point, you may choose not to quit, by hitting C-g. If ! is given, exit from Emacs without saving modified buffers.
(.) r[ead] file
Read in the content of the file file after the specified line.
(.) r[ead] ! command
Read in the output of the shell command command after the specified line.
se[t]
Set a variable's value. See Customizing Constants, for the list of variables you can set.
sh[ell]
Run a subshell in a window.
(.,.) s[ubstitute] /pat/repl/ options count flags
(.,.) & options count flags
On each specified line, the first occurrence of string matching regular expression pat is replaced by replacement pattern repl. Option characters are g and c. If global option character g appears as part of options, all occurrences are substituted. If confirm option character c appears, you will be asked to give confirmation before each substitution. If /pat/repl/ is missing, the last substitution is repeated.
st[op]
Suspend Emacs.
ta[g] tag
Find first definition of tag. If no tag is given, previously given tag is used and next alternate definition is find. By default, the file TAGS in the current directory becomes the selected tags table. You can select another tags table by set command. See Customizing Constants, for details.
und[o]
Undo the last change.
unm[ap] ch
The macro expansion associated with ch is removed.
ve[rsion]
Tell the version number of VIP.
(1,$) w[rite] ! file
Write out specified lines into file file. If no file is given, text will be written to the file associated to the current buffer. Unless ! is given, if file is different from the file associated to the current buffer and if the file file exists, the command will not be executed. Unlike Ex, file becomes the file associated to the current buffer.
(1,$) w[rite]>> file
Write out specified lines at the end of file file. file becomes the file associated to the current buffer.
(1,$) wq ! file
Same as write and then quit. If ! is given, same as write ! then quit.
(.,.) y[ank] register count
Save specified lines into register register. If no register is specified, text will be saved in an anonymous register.
addr ! command
Execute shell command command. The output will be shown in a new window. If addr is given, specified lines will be used as standard input to command.
($) =
Print the line number of the addressed line.
(.,.) > count flags
Shift specified lines to the right. The variable vip-shift-width (default value is 8) determines the amount of shift.
(.,.) < count flags
Shift specified lines to the left. The variable vip-shift-width (default value is 8) determines the amount of shift.
(.,.) ~ options count flags
Repeat the previous substitute command using previous search pattern as pat for matching.

The following Ex commands are available in Vi, but not implemented in VIP.

     abbreviate, list, next, print, preserve, recover, rewind, source,
     unabbreviate, xit, z

Next: , Previous: Ex Command Reference, Up: Top

4 Customization

If you have a file called .vip in your home directory, then it will also be loaded when VIP is loaded. This file is thus useful for customizing VIP.

Next: , Previous: Customization, Up: Customization

4.1 Customizing Constants

An easy way to customize VIP is to change the values of constants used in VIP. Here is the list of the constants used in VIP and their default values.

vip-shift-width 8
The number of columns shifted by > and < command.
vip-re-replace nil
If t then do regexp replace, if nil then do string replace.
vip-search-wrap-around t
If t, search wraps around the buffer.
vip-re-search nil
If t then search is reg-exp search, if nil then vanilla search.
vip-case-fold-search nil
If t search ignores cases.
vip-re-query-replace nil
If t then do reg-exp replace in query replace.
vip-open-with-indent nil
If t then indent to the previous current line when open a new line by o or O command.
vip-tags-file-name "TAGS"
The name of the file used as the tags table.
vip-help-in-insert-mode nil
If t then <C-h> is bound to help-command in insert mode, if nil then it sis bound to delete-backward-char.
You can reset these constants in VIP by the Ex command set. Or you can include a line like this in your .vip file:
     (setq vip-case-fold-search t)

Previous: Customizing Constants, Up: Customization

4.2 Customizing Key Bindings

VIP uses vip-command-mode-map as the local keymap for vi mode. For example, in vi mode, <SPC> is bound to the function vip-scroll. But, if you wish to make <SPC> and some other keys behave like Vi, you can include the following lines in your .vip file.

     (define-key vip-command-mode-map "\C-g" 'vip-info-on-file)
     (define-key vip-command-mode-map "\C-h" 'vip-backward-char)
     (define-key vip-command-mode-map "\C-m" 'vip-next-line-at-bol)
     (define-key vip-command-mode-map " " 'vip-forward-char)
     (define-key vip-command-mode-map "g" 'vip-keyboard-quit)
     (define-key vip-command-mode-map "s" 'vip-substitute)
     (define-key vip-command-mode-map "C" 'vip-change-to-eol)
     (define-key vip-command-mode-map "R" 'vip-change-to-eol)
     (define-key vip-command-mode-map "S" 'vip-substitute-line)
     (define-key vip-command-mode-map "X" 'vip-delete-backward-char)

Up: Top

Appendix A GNU Free Documentation License

Version 1.3, 3 November 2008
     Copyright © 2000, 2001, 2002, 2007, 2008, 2009 Free Software Foundation, Inc.
     http://fsf.org/
     
     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.
  1. PREAMBLE

    The purpose of this License is to make a manual, textbook, or other functional and useful document free in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

    This License is a kind of “copyleft”, which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

    We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

  2. APPLICABILITY AND DEFINITIONS

    This License applies to any manual or other work, in any medium, that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. Such a notice grants a world-wide, royalty-free license, unlimited in duration, to use that work under the conditions stated herein. The “Document”, below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as “you”. You accept the license if you copy, modify or distribute the work in a way requiring permission under copyright law.

    A “Modified Version” of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language.

    A “Secondary Section” is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (Thus, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them.

    The “Invariant Sections” are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. If a section does not fit the above definition of Secondary then it is not allowed to be designated as Invariant. The Document may contain zero Invariant Sections. If the Document does not identify any Invariant Sections then there are none.

    The “Cover Texts” are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A Front-Cover Text may be at most 5 words, and a Back-Cover Text may be at most 25 words.

    A “Transparent” copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not “Transparent” is called “Opaque”.

    Examples of suitable formats for Transparent copies include plain ascii without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

    The “Title Page” means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, “Title Page” means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.

    The “publisher” means any person or entity that distributes copies of the Document to the public.

    A section “Entitled XYZ” means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as “Acknowledgements”, “Dedications”, “Endorsements”, or “History”.) To “Preserve the Title” of such a section when you modify the Document means that it remains a section “Entitled XYZ” according to this definition.

    The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

  3. VERBATIM COPYING

    You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

    You may also lend copies, under the same conditions stated above, and you may publicly display copies.

  4. COPYING IN QUANTITY

    If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

    If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

    If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

    It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

  5. MODIFICATIONS

    You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

    1. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
    2. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
    3. State on the Title page the name of the publisher of the Modified Version, as the publisher.
    4. Preserve all the copyright notices of the Document.
    5. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
    6. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
    7. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
    8. Include an unaltered copy of this License.
    9. Preserve the section Entitled “History”, Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled “History” in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
    10. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the “History” section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
    11. For any section Entitled “Acknowledgements” or “Dedications”, Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
    12. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
    13. Delete any section Entitled “Endorsements”. Such a section may not be included in the Modified Version.
    14. Do not retitle any existing section to be Entitled “Endorsements” or to conflict in title with any Invariant Section.
    15. Preserve any Warranty Disclaimers.

    If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.

    You may add a section Entitled “Endorsements”, provided it contains nothing but endorsements of your Modified Version by various parties—for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

    You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

    The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

  6. COMBINING DOCUMENTS

    You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

    The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

    In the combination, you must combine any sections Entitled “History” in the various original documents, forming one section Entitled “History”; likewise combine any sections Entitled “Acknowledgements”, and any sections Entitled “Dedications”. You must delete all sections Entitled “Endorsements.”

  7. COLLECTIONS OF DOCUMENTS

    You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

    You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

  8. AGGREGATION WITH INDEPENDENT WORKS

    A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an “aggregate” if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

    If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

  9. TRANSLATION

    Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

    If a section in the Document is Entitled “Acknowledgements”, “Dedications”, or “History”, the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

  10. TERMINATION

    You may not copy, modify, sublicense, or distribute the Document except as expressly provided under this License. Any attempt otherwise to copy, modify, sublicense, or distribute it is void, and will automatically terminate your rights under this License.

    However, if you cease all violation of this License, then your license from a particular copyright holder is reinstated (a) provisionally, unless and until the copyright holder explicitly and finally terminates your license, and (b) permanently, if the copyright holder fails to notify you of the violation by some reasonable means prior to 60 days after the cessation.

    Moreover, your license from a particular copyright holder is reinstated permanently if the copyright holder notifies you of the violation by some reasonable means, this is the first time you have received notice of violation of this License (for any work) from that copyright holder, and you cure the violation prior to 30 days after your receipt of the notice.

    Termination of your rights under this section does not terminate the licenses of parties who have received copies or rights from you under this License. If your rights have been terminated and not permanently reinstated, receipt of a copy of some or all of the same material does not give you any rights to use it.

  11. FUTURE REVISIONS OF THIS LICENSE

    The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

    Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License “or any later version” applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. If the Document specifies that a proxy can decide which future versions of this License can be used, that proxy's public statement of acceptance of a version permanently authorizes you to choose that version for the Document.

  12. RELICENSING

    “Massive Multiauthor Collaboration Site” (or “MMC Site”) means any World Wide Web server that publishes copyrightable works and also provides prominent facilities for anybody to edit those works. A public wiki that anybody can edit is an example of such a server. A “Massive Multiauthor Collaboration” (or “MMC”) contained in the site means any set of copyrightable works thus published on the MMC site.

    “CC-BY-SA” means the Creative Commons Attribution-Share Alike 3.0 license published by Creative Commons Corporation, a not-for-profit corporation with a principal place of business in San Francisco, California, as well as future copyleft versions of that license published by that same organization.

    “Incorporate” means to publish or republish a Document, in whole or in part, as part of another Document.

    An MMC is “eligible for relicensing” if it is licensed under this License, and if all works that were first published under this License somewhere other than this MMC, and subsequently incorporated in whole or in part into the MMC, (1) had no cover texts or invariant sections, and (2) were thus incorporated prior to November 1, 2008.

    The operator of an MMC Site may republish an MMC contained in the site under CC-BY-SA on the same site at any time before August 1, 2009, provided the MMC is eligible for relicensing.

ADDENDUM: How to use this License for your documents

To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page:

       Copyright (C)  year  your name.
       Permission is granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version 1.3
       or any later version published by the Free Software Foundation;
       with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
       Texts.  A copy of the license is included in the section entitled ``GNU
       Free Documentation License''.

If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with...Texts.” line with this:

         with the Invariant Sections being list their titles, with
         the Front-Cover Texts being list, and with the Back-Cover Texts
         being list.

If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation.

If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.

Key Index

Concept Index