path: root/runtime/doc/vi_diff.txt

*vi_diff.txt*   For Vim version 7.0aa.  Last change: 2005 Feb 21


		  VIM REFERENCE MANUAL    by Bram Moolenaar


Differences between Vim and Vi				*vi-differences*

Throughout the help files differences between Vim and Vi/Ex are given in
curly braces, like "{not in Vi}".  This file only lists what has not been
mentioned in other files and gives an overview.

Vim is mostly POSIX 1003.2-1 compliant.  The only command known to be missing
is ":open".  There are probably a lot of small differences (either because Vim
is missing something or because Posix is beside the mark).

1. Simulated command			|simulated-command|
2. Missing options			|missing-options|
3. Limits				|limits|
4. The most interesting additions	|vim-additions|
5. Other vim features			|other-features|
6. Command-line arguments		|cmdline-arguments|
7. POSIX compliance			|posix-compliance|

==============================================================================
1. Simulated command					*simulated-command*

This command is in Vi, but Vim only simuates it:

							*:o* *:op* *:open*
:[range]o[pen]			Works like |:visual|: end Ex mode.
				{Vi: start editing in open mode}

:[range]o[pen] /pattern/	As above, additionally move the cursor to the
				column where "pattern" matches in the cursor
				line.

Vim does not support open mode, since it's not really useful.  For those
situations where ":open" would start open mode Vim will leave Ex mode, which
allows executing the same commands, but updates the whole screen instead of
only one line.

==============================================================================
2. Missing options					*missing-options*

These options are in the Unix Vi, but not in Vim.  If you try to set one of
them you won't get an error message, but the value is not used and cannot be
printed.

autoprint (ap)		boolean	(default on)		*'autoprint'* *'ap'*
beautify (bf)		boolean	(default off)		*'beautify'* *'bf'*
flash (fl)		boolean	(default ??)		*'flash'* *'fl'*
graphic (gr)		boolean	(default off)		*'graphic'* *'gr'*
hardtabs (ht)		number	(default 8)		*'hardtabs'* *'ht'*
	number of spaces that a <Tab> moves on the display
mesg			boolean	(default on)		*'mesg'*
novice			boolean	(default off)		*'novice'*
open			boolean	(default on)		*'open'*
optimize (op)		boolean	(default off)		*'optimize'* *'op'*
redraw			boolean	(default off)		*'redraw'*
slowopen (slow)		boolean	(default off)		*'slowopen'* *'slow'*
sourceany		boolean	(default off)		*'sourceany'*
w300			number	(default 23)		*'w300'*
w1200			number	(default 23)		*'w1200'*
w9600			number	(default 23)		*'w9600'*

==============================================================================
3. Limits						*limits*

Vim has only a few limits for the files that can be edited {Vi: can not handle
<Nul> characters and characters above 128, has limited line length, many other
limits}.
							*E340*
Maximum line length	   On machines with 16-bit ints (Amiga and MS-DOS real
			   mode): 32767, otherwise 2147483647 characters.
			   Longer lines are split.
Maximum number of lines	   2147483647 lines.
Maximum file size	   2147483647 bytes (2 Gbyte) when a long integer is
			   32 bits.  Much more for 64 bit longs.  Also limited
			   by available disk space for the |swap-file|.
							*E75*
Length of a file path	   Unix and Win32: 1024 characters, otherwise 256
			   characters (or as much as the system supports).
Length of an expanded string option
			   Unix and Win32: 1024 characters, otherwise 256
			   characters
Maximum display width	   Unix and Win32: 1024 characters, otherwise 255
			   characters
Maximum lhs of a mapping   50 characters.
Number of highlighting different types: 223

Information for undo and text in registers is kept in memory, thus when making
(big) changes the amount of (virtual) memory available limits the number of
undo levels and the text that can be kept in registers.  Other things are also
kept in memory:  Command-line history, error messages for Quickfix mode, etc.

Memory usage limits
-------------------

The option 'maxmem' ('mm') is used to set the maximum memory used for one
buffer (in kilobytes).  'maxmemtot' is used to set the maximum memory used for
all buffers (in kilobytes).  The defaults depend on the system used.  For the
Amiga and MS-DOS, 'maxmemtot' is set depending on the amount of memory
available.  If you don't like Vim to swap to a file, set 'maxmem' and
'maxmemtot' to a very large value.  The swap file will then only be used for
recovery.  If you don't want a swap file at all, set 'updatecount' to 0, or
use the "-n" argument when starting Vim.  Note that the 'maxmem' option is
only used when a buffer is created.  Changing this option does not affect
buffers that have already been loaded.  Thus you can set it to different
values for different files.  'maxmemtot' works always.

==============================================================================
4. The most interesting additions			*vim-additions*

Vi compatibility.					|'compatible'|
	Although Vim is 99% Vi compatible, some things in Vi can be
	considered to be a bug, or at least need improvement.  But still, Vim
	starts in a mode which behaves like the "real" Vi as much as possible.
	To make Vim behave a little bit better, try resetting the 'compatible'
	option:
		:set nocompatible
	Or start Vim with the "-N" argument:
		vim -N
	This is done automatically if you have a .vimrc file.  See |startup|.
	The 'cpoptions' option can be used to set Vi compatibility on/off for
	a number of specific items.

Support for different systems.
	Vim can be used on:
	- All Unix systems (it works on all systems it was tested on, although
	  the GUI and Perl interface may not work everywhere).
	- Amiga (500, 1000, 1200, 2000, 3000, 4000, ...).
	- MS-DOS in real-mode (no additional drivers required).
	- In protected mode on Windows 3.1 and MS-DOS (DPMI driver required).
	- Windows 95 and Windows NT, with support for long file names.
	- OS/2 (needs emx.dll)
	- Atari MiNT
	- VMS
	- BeOS
	- Macintosh
	- Risc OS
	- IBM OS/390

Multi level undo.					|undo|
	'u' goes backward in time, 'CTRL-R' goes forward again.  Set option
	'undolevels' to the number of changes to be remembered (default 1000).
	Set 'undolevels' to 0 for a vi-compatible one level undo. Set it to
	-1 for no undo at all.

	When all changes in a buffer have been undone, the buffer is not
	considered changed anymore.  You can exit it with :q, without <!>.

Graphical User Interface (GUI)				|gui|
	Included support for GUI: menu's, mouse, scrollbars, etc.  You can
	define your own menus.  Better support for CTRL/SHIFT/ALT keys in
	combination with special keys and mouse.  Supported for various
	platforms, such as X11 (with Motif and Athena interfaces), GTK, Win32
	(Windows 95 and later), BeOS, Amiga and Macintosh.

Multiple windows and buffers.				|windows.txt|
	Vim can split the screen into several windows, each editing a
	different buffer or the same buffer at a different location.  Buffers
	can still be loaded (and changed) but not displayed in a window.  This
	is called a hidden buffer.  Many commands and options have been added
	for this facility.

Syntax highlighting.					|:syntax|
	Vim can highlight keywords, patterns and other things.  This is
	defined by a number of ":syntax" commands, and can be made to
	highlight most languages and file types.  A number of files are
	included for highlighting the most common languages, like C, C++,
	Java, Pascal, Makefiles, shell scripts, etc.  The colors used for
	highlighting can be defined for ordinary terminals, color terminals
	and the GUI with the ":highlight" command.

Folding							|folding|
	A range of lines can be shown as one "folded" line.  This allows
	overviewing a file and moving blocks of text around quickly.
	Folds can be created manually, from the syntax of the file, by indent,
	etc.

Plugins							|add-plugin|
	The functionality can be extended by dropping a plugin file in the
	right directory.  That's an easy way to start using Vim scripts
	written by others.  Plugins can be for all kind of files, or
	specifically for a filetype.

Repeat a series of commands.				|q|
	"q{c}" starts recording typed characters into named register {c}
	(append to the register if register name is uppercase).  A subsequent
	"q" stops recording.  The register can then be executed with the
	"@{c}" command.  This is very useful to repeat a complex action.

Flexible insert mode.					|ins-special-special|
	The arrow keys can be used in insert mode to move around in the file.
	This breaks the insert in two parts as far as undo and redo is
	concerned.

	CTRL-O can be used to execute a single command-mode command.  This is
	almost the same as hitting <Esc>, typing the command and doing "a".

Visual mode.						|Visual-mode|
	Visual can be used to first highlight a piece of text and then give a
	command to do something with it.  This is an (easy to use) alternative
	to first giving the operator and then moving to the end of the text
	to be operated upon.  "v" and "V" are used to start Visual mode.  "v"
	works on characters and 'V' on lines.  Move the cursor to extend the
	Visual part.  It is shown highlighted on the screen.  By typing "o"
	the other end of the Visual text can be moved.  The Visual text can
	be affected by an operator:
		d	delete
		c	change
		y	yank
		> or <	insert or delete indent
		!	filter through external program
		=	filter through indent
		:	start ":" command for the Visual lines.
		gq	format text to 'textwidth' columns
		J	join lines
		~	swap case
		u	make lowercase
		U	make uppercase

Block operators.					|visual-block|
	With Visual a rectangular block of text can be selected.  Start Visual
	with CTRL-V.  The block can be deleted ("d"), yanked ("y") or its case
	can be changed ("~", "u" and "U").  A deleted or yanked block can be
	put into the text with the "p" and "P" commands.

Online help system.					|:help|
	Help is displayed in a window.  The usual commands can be used to
	move around, search for a string, etc.  Tags can be used to jump
	around in the help files, just like hypertext links.  The ":help"
	command takes an argument to quickly jump to the info on a subject.
	<F1> is the quick access to the help system.  The name of the help
	index file can be set with the 'helpfile' option.

Command-line editing and history.			|cmdline-editing|
	You can insert or delete at any place in the command-line using the
	cursor keys.  The right/left cursor keys can be used to move
	forward/backward one character.  The shifted right/left cursor keys
	can be used to move forward/backward one word.  CTRL-B/CTRL-E can be
	used to go to the begin/end of the command-line.

							|cmdline-history|
	The command-lines are remembered.  The up/down cursor keys can be used
	to recall previous command-lines.  The 'history' option can be set to
	the number of lines that will be remembered.  There is a separate
	history for commands and for search patterns.

Command-line completion.				|cmdline-completion|
	While entering a command-line (on the bottom line of the screen)
	<Tab> can be typed to complete
	   what		example		~
	- command	:e<Tab>
	- tag		:ta scr<Tab>
	- option	:set sc<Tab>
	- option value  :set hf=<Tab>
	- file name	:e ve<Tab>
	- etc.

	If there are multiple matches, CTRL-N (next) and CTRL-P (previous)
	will walk through the matches.  <Tab> works like CTRL-N, but wraps
	around to the first match.

	The 'wildchar' option can be set to the character for command-line
	completion, <Tab> is the default.  CTRL-D can be typed after an
	(incomplete) wildcard; all matches will be listed.  CTRL-A will insert
	all matches.  CTRL-L will insert the longest common part of the
	matches.

Insert-mode completion					|ins-completion|
	In insert mode the CTRL-N and CTRL-P keys can be used to complete a
	word that has previously been used.	|i_CTRL-N|
	With CTRL-X another mode is entered, through which completion can be
	done for:
	|i_CTRL-X_CTRL-F|	file names
	|i_CTRL-X_CTRL-K|	words from 'dictionary' files
	|i_CTRL-X_CTRL-T|	words from 'thesaurus' files
	|i_CTRL-X_CTRL-I|	words from included files
	|i_CTRL-X_CTRL-L|	whole lines
	|i_CTRL-X_CTRL-]|	words from the tags file
	|i_CTRL-X_CTRL-D|	definitions or macros

Long line support					|'wrap'| |'linebreak'|
	If the 'wrap' option is off, long lines will not wrap and only part
	of them will be shown.  When the cursor is moved to a part that is not
	shown, the screen will scroll horizontally.  The minimum number of
	columns to scroll can be set with the 'sidescroll' option.  The "zh"
	and "zl" commands can be used to scroll sideways.
	Alternatively, long lines are broken in between words when the
	'linebreak' option is set.  This allows editing a single-line
	paragraph conveniently (e.g. when the text is later read into a DTP
	program).  Move the cursor up/down with the "gk" and "gj" commands.

Text formatting.					|formatting|
	The 'textwidth' option can be used to automatically limit the line
	length.  This supplements the 'wrapmargin' option of Vi, which was not
	very useful.  The "gq" operator can be used to format a piece of text
	(for example, "gqap" formats the current paragraph).  Commands for
	text alignment: ":center", ":left" and ":right".

Extended search patterns				|pattern|
	There are many extra items to match various text items.  Examples:
	A "\n" can be used in a search pattern to match a line break.
	"x\{2,4}" matches "x" 2 to 4 times.
	"\s" matches a white space character.

Edit-compile-edit speedup.				|quickfix|
	The ":make" command can be used to run the compilation and jump to
	the first error.  Alternatively Vim can be started with the "-q"
	option from the compiler.  A file with compiler error messages is
	interpreted.  Vim starts editing at the first error.

	Each line in the error file is scanned for the name of a file, line
	number and error message.  The 'errorformat' option can be set to a
	list of scanf-like strings to handle output from many compilers.

	The ":cn" command can be used to jump to the next error.
	":cl" lists all the error messages.  Other commands are available
	(almost the same as with Manx's Z editor on the Amiga).
	The 'makeef' option has the name of the file with error messages.
	The 'makeprg' option contains the name of the program to be executed
	with the ":make" command.
	The 'shellpipe' option contains the string to be used to put the
	output of the compiler into the errorfile.

Improved indenting for C programs			|'cindent'|
	When the 'cindent' option is on the indent of each line is
	automatically adjusted.  C syntax is mostly recognized.  The indent
	for various styles can be set with 'cinoptions'.  The keys to trigger
	indenting can be set with 'cinkeys'.

	Comments can be automatically formatted.  The 'comments' option can be
	set to the characters that start and end a comment.  This works best
	for C code, but also works for e-mail (">" at start of the line) and
	other types of text.  The "=" operator can be used to re-indent
	lines.

Searching for words in include files			|include-search|
	The "[i" command can be used to search for a match of the word under
	the cursor in the current and included files.  The 'include' option
	can be set the a pattern that describes a command to include a file
	(the default is for C programs).
	The "[I" command lists all matches, the "[ CTRL-I" command jumps to
	a match.
	The "[d", "[D" and "[ CTRL-D" commands do the same, but only for
	lines where the pattern given with the 'define' option matches.

Automatic commands					|autocommand|
	Commands can be automatically executed when reading a file, writing a
	file, jumping to another buffer, etc., depending on the file name.
	This is useful to set options and mappings for C programs,
	documentation, plain text, e-mail, etc.  This also makes it possible
	to edit compressed files.

Scripts and Expressions					|expression|
	Commands have been added to form up a simple but powerful script
	language.
	|:if|		Conditional execution, which can be used for example
			to set options depending on the value of $TERM.
	|:while|	Repeat a number of commands.
	|:echo|		Print the result of an expression.
	|:let|		Assign a value to an internal variable, option, etc.
	|:execute|	Execute a command formed by an expression.
	etc.

Viminfo							|viminfo-file|
	The command-line history, marks and registers can be stored in a file
	that is read on startup.  This can be used to repeat a search command
	or command-line command after exiting and restarting Vim.  It is also
	possible to jump right back to where the last edit stopped with "'0".
	The 'viminfo' option can be set to select which items to store in the
	.viminfo file.  This is off by default.

Mouse support						|mouse-using|
	The mouse is supported in the GUI version, in an xterm for Unix, for
	Linux with gpm, for MS-DOS, and Win32.  It can be used to position the
	cursor, select the visual area, paste a register, etc.

Usage of key names					|<>| |key-notation|
	Special keys now all have a name like <Up>, <End>, etc.
	This name can be used in mappings, to make it easy to edit them.

Editing binary files					|edit-binary|
	Vim can edit binary files.  You can change a few characters in an
	executable file, without corrupting it.  Vim doesn't remove NUL
	characters (they are represented as <NL> internally).
	|-b|		command-line argument to start editing a binary file
	|'binary'|	Option set by "-b".  Prevents adding an <EOL> for the
			last line in the file.

Multi-language support					|multi-lang|
	Files in double-byte or multi-byte encodings can be edited.  There is
	UTF-8 support to be able to edit various languages at the same time,
	without switching fonts. |UTF-8|
	Messages and menus are available in different languages.

==============================================================================
5. Other vim features					*other-features*

A random collection of nice extra features.


When Vim is started with "-s scriptfile", the characters read from
"scriptfile" are treated as if you typed them.  If end of file is reached
before the editor exits, further characters are read from the console.

The "-w" option can be used to record all typed characters in a script file.
This file can then be used to redo the editing, possibly on another file or
after changing some commands in the script file.

The "-o" option opens a window for each argument.  "-o4" opens four windows.

Vi requires several termcap entries to be able to work full-screen.  Vim only
requires the "cm" entry (cursor motion).


In command mode:

When the 'showcmd' option is set, the command characters are shown in the last
line of the screen.  They are removed when the command is finished.

If the 'ruler' option is set, the current cursor position is shown in the
last line of the screen.

"U" still works after having moved off the last changed line and after "u".

Characters with the 8th bit set are displayed.  The characters between '~' and
0xa0 are displayed as "~?", "~@", "~A", etc., unless they are included in the
'isprint' option.

"][" goes to the next ending of a C function ('}' in column 1).
"[]" goes to the previous ending of a C function ('}' in column 1).

"]f", "[f" and "gf" start editing the file whose name is under the cursor.
CTRL-W f splits the window and starts editing the file whose name is under
the cursor.

"*" searches forward for the identifier under the cursor, "#" backward.
"K" runs the program defined by the 'keywordprg' option, with the identifier
under the cursor as argument.

"%" can be preceded with a count.  The cursor jumps to the line that
percentage down in the file.  The normal "%" function to jump to the matching
brace skips braces inside quotes.

With the CTRL-] command, the cursor may be in the middle of the identifier.

The used tags are remembered.  Commands that can be used with the tag stack
are CTRL-T, ":pop" and ":tag".  ":tags" lists the tag stack.

The 'tags' option can be set to a list of tag file names.  Thus multiple
tag files can be used.  For file names that start with "./", the "./" is
replaced with the path of the current file.  This makes it possible to use a
tags file in the same directory as the file being edited.

Previously used file names are remembered in the alternate file name list.
CTRL-^ accepts a count, which is an index in this list.
":files" command shows the list of alternate file names.
"#<N>" is replaced with the <N>th alternate file name in the list.
"#<" is replaced with the current file name without extension.

Search patterns have more features.  The <NL> character is seen as part of the
search pattern and the substitute string of ":s".  Vi sees it as the end of
the command.

Searches can put the cursor on the end of a match and may include a character
offset.

Count added to "~", ":next", ":Next", "n" and "N".

The command ":next!" with 'autowrite' set does not write the file.  In vi the
file was written, but this is considered to be a bug, because one does not
expect it and the file is not written with ":rewind!".

In Vi when entering a <CR> in replace mode deletes a character only when 'ai'
is set (but does not show it until you hit <Esc>).  Vim always deletes a
character (and shows it immediately).

Added :wnext command.  Same as ":write" followed by ":next".

The ":w!" command always writes, also when the file is write protected.  In Vi
you would have to do ":!chmod +w %" and ":set noro".

When 'tildeop' has been set, "~" is an operator (must be followed by a
movement command).

With the "J" (join) command you can reset the 'joinspaces' option to have only
one space after a period (Vi inserts two spaces).

"cw" can be used to change white space formed by several characters (Vi is
confusing: "cw" only changes one space, while "dw" deletes all white space).

"o" and "O" accept a count for repeating the insert (Vi clears a part of
display).

Flags after Ex commands not supported (no plans to include it).

On non-UNIX systems ":cd" command shows current directory instead of going to
the home directory (there isn't one).  ":pwd" prints the current directory on
all systems.

After a ":cd" command the file names (in the argument list, opened files)
still point to the same files.  In Vi ":cd" is not allowed in a changed file;
otherwise the meaning of file names change.

":source!" command reads Vi commands from a file.

":mkexrc" command writes current modified options and mappings to a ".exrc"
file.  ":mkvimrc" writes to a ".vimrc" file.

No check for "tail recursion" with mappings.  This allows things like
":map! foo ^]foo".

When a mapping starts with number, vi loses the count typed before it (e.g.
when using the mapping ":map g 4G" the command "7g" goes to line 4).  T