A sequence of single character flags. When a character is present this indicates Vi-compatible behavior. This is used for things where not being Vi-compatible is mostly or sometimes preferred. 'cpoptions' stands for "compatible-options". Commas can be added for readability. To avoid problems with flags that are added in the future, use the "+=" and "-=" feature of ":set" |add-option-flags|.

NOTE: This option is set to the Vi default value when 'compatible' is set and to the Vim default value when 'compatible' is reset.

NOTE: In a |Vim9| script, when vim9script is encountered, the value is saved, 'cpoptions' is set to the Vim default, and the saved value is restored at the end of the script. Changes to the value of 'cpoptions' will be applied to the saved value, but keep in mind that removing a flag that is not present when 'cpoptions' is changed has no effect. In the |.vimrc| file the value is not restored, thus using vim9script in the |.vimrc| file results in using the Vim default.

NOTE: This option is set to the POSIX default value at startup when the Vi default value would be used and the $VIM_POSIX environment variable exists |posix|. This means Vim tries to behave like the POSIX specification.

contains	behavior	~

a	When included, a ":read" command with a file name
	argument will set the alternate file name for the
	current window.

A	When included, a ":write" command with a file name
	argument will set the alternate file name for the
	current window.

b	"\|" in a ":map" command is recognized as the end of
	the map command.  The '\' is included in the mapping,
	the text after the '|' is interpreted as the next
	command.  Use a CTRL-V instead of a backslash to
	include the '|' in the mapping.  Applies to all
	mapping, abbreviation, menu and autocmd commands.
	See also |map_bar|.

B	A backslash has no special meaning in mappings,
	abbreviations, user commands and the "to" part of the
	menu commands.  Remove this flag to be able to use a
	backslash like a CTRL-V.  For example, the command
	":map X \<Esc>" results in X being mapped to:
		'B' included:	"\^["	 (^[ is a real <Esc>)
		'B' excluded:	"<Esc>"  (5 characters)
		('<' excluded in both cases)

c	Searching continues at the end of any match at the
	cursor position, but not further than the start of the
	next line.  When not present searching continues
	one character from the cursor position.  With 'c'
	"abababababab" only gets three matches when repeating
	"/abab", without 'c' there are five matches.

C	Do not concatenate sourced lines that start with a
	backslash.  See |line-continuation|.

d	Using "./" in the 'tags' option doesn't mean to use
	the tags file relative to the current file, but the
	tags file in the current directory.

D	Can't use CTRL-K to enter a digraph after Normal mode
	commands with a character argument, like |r|, |f| and
	|t|.

e	When executing a register with ":@r", always add a
	<CR> to the last line, also when the register is not
	linewise.  If this flag is not present, the register
	is not linewise and the last line does not end in a
	<CR>, then the last line is put on the command-line
	and can be edited before hitting <CR>.

E	It is an error when using "y", "d", "c", "g~", "gu" or
	"gU" on an Empty region.  The operators only work when
	at least one character is to be operated on.  Example:
	This makes "y0" fail in the first column.

f	When included, a ":read" command with a file name
	argument will set the file name for the current buffer,
	if the current buffer doesn't have a file name yet.

F	When included, a ":write" command with a file name
	argument will set the file name for the current
	buffer, if the current buffer doesn't have a file name
	yet.  Also see |cpo-P|.

g	Goto line 1 when using ":edit" without argument.

H	When using "I" on a line with only blanks, insert
	before the last blank.  Without this flag insert after
	the last blank.

i	When included, interrupting the reading of a file will
	leave it modified.

I	When moving the cursor up or down just after inserting
	indent for 'autoindent', do not delete the indent.

j	When joining lines, only add two spaces after a '.',
	not after '!' or '?'.  Also see 'joinspaces'.

J	A |sentence| has to be followed by two spaces after
	the '.', '!' or '?'.  A <Tab> is not recognized as
	white space.

k	Disable the recognition of raw key codes in
	mappings, abbreviations, and the "to" part of menu
	commands.  For example, if <Key> sends ^[OA (where ^[
	is <Esc>), the command ":map X ^[OA" results in X
	being mapped to:
		'k' included:	"^[OA"	 (3 characters)
		'k' excluded:	"<Key>"  (one key code)
	Also see the '<' flag below.

K	Don't wait for a key code to complete when it is
	halfway a mapping.  This breaks mapping <F1><F1> when
	only part of the second <F1> has been read.  It
	enables cancelling the mapping by typing <F1><Esc>.

l	Backslash in a [] range in a search pattern is taken
	literally, only "\]", "\^", "\-" and "\\" are special.
	See |/[]|
	   'l' included: "/[ \t]"  finds <Space>, '\' and 't'
	   'l' excluded: "/[ \t]"  finds <Space> and <Tab>
	Also see |cpo-\|.

L	When the 'list' option is set, 'wrapmargin',
	'textwidth', 'softtabstop' and Virtual Replace mode
	(see |gR|) count a <Tab> as two characters, instead of
	the normal behavior of a <Tab>.

m	When included, a showmatch will always wait half a
	second.  When not included, a showmatch will wait half
	a second or until a character is typed.  |'showmatch'|

M	When excluded, "%" matching will take backslashes into
	account.  Thus in "( \( )" and "\( ( \)" the outer
	parenthesis match.  When included "%" ignores
	backslashes, which is Vi compatible.

n	When included, the column used for 'number' and
	'relativenumber' will also be used for text of wrapped
	lines.

o	Line offset to search command is not remembered for
	next search.

O	Don't complain if a file is being overwritten, even
	when it didn't exist when editing it.  This is a
	protection against a file unexpectedly created by
	someone else.  Vi didn't complain about this.

p	Vi compatible Lisp indenting.  When not present, a
	slightly better algorithm is used.

P	When included, a ":write" command that appends to a
	file will set the file name for the current buffer, if
	the current buffer doesn't have a file name yet and
	the 'F' flag is also included |cpo-F|.

q	When joining multiple lines leave the cursor at the
	position where it would be when joining two lines.

r	Redo ("." command) uses "/" to repeat a search
	command, instead of the actually used search string.

R	Remove marks from filtered lines.  Without this flag
	marks are kept like |:keepmarks| was used.

s	Set buffer options when entering the buffer for the
	first time.  This is like it is in Vim version 3.0.
	And it is the default.  If not present the options are
	set when the buffer is created.

S	Set buffer options always when entering a buffer
	(except 'readonly', 'fileformat', 'filetype' and
	'syntax').  This is the (most) Vi compatible setting.
	The options are set to the values in the current
	buffer.  When you change an option and go to another
	buffer, the value is copied.  Effectively makes the
	buffer options global to all buffers.

	's'    'S'     copy buffer options
	no     no      when buffer created
	yes    no      when buffer first entered (default)
	 X     yes     each time when buffer entered (vi comp.)

t	Search pattern for the tag command is remembered for
	"n" command.  Otherwise Vim only puts the pattern in
	the history for search pattern, but doesn't change the
	last used search pattern.

u	Undo is Vi compatible.  See |undo-two-ways|.

v	Backspaced characters remain visible on the screen in
	Insert mode.  Without this flag the characters are
	erased from the screen right away.  With this flag the
	screen newly typed text overwrites backspaced
	characters.

w	When using "cw" on a blank character, only change one
	character and not all blanks until the start of the
	next word.

W	Don't overwrite a readonly file.  When omitted, ":w!"
	overwrites a readonly file, if possible.

x	<Esc> on the command-line executes the command-line.
	The default in Vim is to abandon the command-line,
	because <Esc> normally aborts a command.  |c_<Esc>|

X	When using a count with "R" the replaced text is
	deleted only once.  Also when repeating "R" with "."
	and a count.

y	A yank command can be redone with ".".  Think twice if
	you really want to use this, it may break some
	plugins, since most people expect "." to only repeat a
	change.

Z	When using "w!" while the 'readonly' option is set,
	don't reset 'readonly'.

!	When redoing a filter command, use the last used
	external command, whatever it was.  Otherwise the last
	used -filter- command is used.

$	When making a change to one line, don't redisplay the
	line, but put a '$' at the end of the changed text.
	The changed text will be overwritten when you type the
	new text.  The line is redisplayed if you type any
	command that moves the cursor from the insertion
	point.

%	Vi-compatible matching is done for the "%" command.
	Does not recognize "#if", "#endif", etc.
	Does not recognize "/*" and "* /".
	Parens inside single and double quotes are also
	counted, causing a string that contains a paren to
	disturb the matching.  For example, in a line like
	"if (strcmp("foo(", s))" the first paren does not
	match the last one.  When this flag is not included,
	parens inside single and double quotes are treated
	specially.  When matching a paren outside of quotes,
	everything inside quotes is ignored.  When matching a
	paren inside quotes, it will find the matching one (if
	there is one).  This works very well for C programs.
	This flag is also used for other features, such as
	C-indenting.

-	When included, a vertical movement command fails when
	it would go above the first line or below the last
	line.  Without it the cursor moves to the first or
	last line, unless it already was in that line.
	Applies to the commands "-", "k", CTRL-P, "+", "j",
	CTRL-N, CTRL-J and ":1234".

+	When included, a ":write file" command will reset the
	'modified' flag of the buffer, even though the buffer
	itself may still be different from its file.

*	Use ":*" in the same way as ":@".  When not included,
	":*" is an alias for ":'<,'>", select the Visual area.

<	Disable the recognition of special key codes in |<>|
	form in mappings, abbreviations, and the "to" part of
	menu commands.  For example, the command
	":map X <Tab>" results in X being mapped to:
		'<' included:	"<Tab>"  (5 characters)
		'<' excluded:	"^I"	 (^I is a real <Tab>)
	Also see the 'k' flag above.

>	When appending to a register, put a line break before
	the appended text.

;	When using |,| or |;| to repeat the last |t| search
	and the cursor is right in front of the searched
	character, the cursor won't move. When not included,
	the cursor would skip over it and jump to the
	following occurrence.

POSIX flags. These are not included in the Vi default value, except when $VIM_POSIX was set on startup. |posix|

contains	behavior	~

#	A count before "D", "o" and "O" has no effect.

&	When ":preserve" was used keep the swap file when
	exiting normally while this buffer is still loaded.
	This flag is tested when exiting.

\	Backslash in a [] range in a search pattern is taken
	literally, only "\]" is special  See |/[]|
	   '\' included: "/[ \-]"  finds <Space>, '\' and '-'
	   '\' excluded: "/[ \-]"  finds <Space> and '-'
	Also see |cpo-l|.

/	When "%" is used as the replacement string in a |:s|
	command, use the previous replacement string. |:s%|

{	The |{| and |}| commands also stop at a "{" character
	at the start of a line.

.	The ":chdir" and ":cd" commands fail if the current
	buffer is modified, unless ! is used.  Vim doesn't
	need this, since it remembers the full path of an
	opened file.

|	The value of the $LINES and $COLUMNS environment
	variables overrule the terminal size values obtained
	with system specific functions.