# Vim documentation: helphelp

main help file

    *helphelp.txt*	For Vim version 8.2.  Last change: 2019 Oct 18

    		  VIM REFERENCE MANUAL    by Bram Moolenaar

    Help on help files					*helphelp*

    1. Help commands		|online-help|
    2. Translated help files	|help-translated|
    3. Writing help files		|help-writing|

    ==============================================================================

    1. Help commands					*online-help*

    			*help* *<Help>* *:h* *:help* *<F1>* *i_<F1>* *i_<Help>*
    <Help>		or
    :h[elp]			Open a window and display the help file in read-only
    			mode.  If there is a help window open already, use
    			that one.  Otherwise, if the current window uses the
    			full width of the screen or is at least 80 characters
    			wide, the help window will appear just above the
    			current window.  Otherwise the new window is put at
    			the very top.
    			The 'helplang' option is used to select a language, if
    			the main help file is available in several languages.

    						*{subject}* *E149* *E661*
    :h[elp] {subject}	Like ":help", additionally jump to the tag {subject}.
    			For example:
    				:help options

     			{subject} can include wildcards such as "*", "?" and
    			"[a-z]":
    			   :help z?	jump to help for any "z" command
    			   :help z.	jump to the help for "z."
    			But when a tag exists it is taken literally:
    			   :help :?	jump to help for ":?"

    			If there is no full match for the pattern, or there
    			are several matches, the "best" match will be used.
    			A sophisticated algorithm is used to decide which
    			match is better than another one.  These items are
    			considered in the computation:
    			- A match with same case is much better than a match
    			  with different case.
    			- A match that starts after a non-alphanumeric
    			  character is better than a match in the middle of a
    			  word.
    			- A match at or near the beginning of the tag is
    			  better than a match further on.
    			- The more alphanumeric characters match, the better.
    			- The shorter the length of the match, the better.

    			The 'helplang' option is used to select a language, if
    			the {subject} is available in several languages.
    			To find a tag in a specific language, append "@ab",
    			where "ab" is the two-letter language code.  See
    			|help-translated|.

    			Note that the longer the {subject} you give, the less
    			matches will be found.  You can get an idea how this
    			all works by using commandline completion (type CTRL-D
    			after ":help subject" |c_CTRL-D|).
    			If there are several matches, you can have them listed
    			by hitting CTRL-D.  Example:
    				:help cont<Ctrl-D>

     			Instead of typing ":help CTRL-V" to search for help
    			for CTRL-V you can type:
    				:help ^V
     			This also works together with other characters, for
    			example to find help for CTRL-V in Insert mode:
    				:help i^V

    			It is also possible to first do ":help" and then
    			use ":tag {pattern}" in the help window.  The
    			":tnext" command can then be used to jump to other
    			matches, "tselect" to list matches and choose one.
    				:help index
    				:tselect /.*mode

     			When there is no argument you will see matches for
    			"help", to avoid listing all possible matches (that
    			would be very slow).
    			The number of matches displayed is limited to 300.

    			The `:help` command can be followed by '|' and another
    			command, but you don't need to escape the '|' inside a
    			help command.  So these both work:
    				:help |
    				:help k| only
     			Note that a space before the '|' is seen as part of
    			the ":help" argument.
    			You can also use <LF> or <CR> to separate the help
    			command from a following command.  You need to type
    			CTRL-V first to insert the <LF> or <CR>.  Example:
    				:help so<C-V><CR>only

    :h[elp]! [subject]	Like ":help", but in non-English help files prefer to
    			find a tag in a file with the same language as the
    			current file.  See |help-translated|.

    						 	*:helpc* *:helpclose*
    :helpc[lose]		Close one help window, if there is one.
    			Vim will try to restore the window layout (including
    			cursor position) to the same layout it was before
    			opening the help window initially.  This might cause
    			triggering several autocommands.

    							*:helpg* *:helpgrep*
    :helpg[rep] {pattern}[@xx]
    			Search all help text files and make a list of lines
    			in which {pattern} matches.  Jumps to the first match.
    			The optional [@xx] specifies that only matches in the
    			"xx" language are to be found.
    			You can navigate through the matches with the
    			|quickfix| commands, e.g., |:cnext| to jump to the
    			next one.  Or use |:cwindow| to get the list of
    			matches in the quickfix window.
    			{pattern} is used as a Vim regexp |pattern|.
    			'ignorecase' is not used, add "\c" to ignore case.
    			Example for case sensitive search:
    				:helpgrep Uganda
     			Example for case ignoring search:
    				:helpgrep uganda\c
     			Example for searching in French help:
    				:helpgrep backspace@fr
     			The pattern does not support line breaks, it must
    			match within one line.  You can use |:grep| instead,
    			but then you need to get the list of help files in a
    			complicated way.
    			Cannot be followed by another command, everything is
    			used as part of the pattern.  But you can use
    			|:execute| when needed.
    			Compressed help files will not be searched (Fedora
    			compresses the help files).

    							*:lh* *:lhelpgrep*
    :lh[elpgrep] {pattern}[@xx]
    			Same as ":helpgrep", except the location list is used
    			instead of the quickfix list.  If the help window is
    			already opened, then the location list for that window
    			is used.  Otherwise, a new help window is opened and
    			the location list for that window is set.  The
    			location list for the current window is not changed
    			then.

    							*:exu* *:exusage*
    :exu[sage]		Show help on Ex commands.  Added to simulate the Nvi
    			command.

    							*:viu* *:viusage*
    :viu[sage]		Show help on Normal mode commands.  Added to simulate
    			the Nvi command.

    When no argument is given to |:help| the file given with the 'helpfile' option
    will be opened.  Otherwise the specified tag is searched for in all "doc/tags"
    files in the directories specified in the 'runtimepath' option.

    The initial height of the help window can be set with the 'helpheight' option
    (default 20).

    Jump to specific subjects by using tags.  This can be done in two ways:
    - Use the "CTRL-]" command while standing on the name of a command or option.
      This only works when the tag is a keyword.  "<C-Leftmouse>" and
      "g<LeftMouse>" work just like "CTRL-]".
    - use the ":ta {subject}" command.  This also works with non-keyword
      characters.

    Use CTRL-T or CTRL-O to jump back.
    Use ":q" to close the help window.

    If there are several matches for an item you are looking for, this is how you
    can jump to each one of them:
    1. Open a help window
    2. Use the ":tag" command with a slash prepended to the tag.  E.g.:
    	:tag /min
    3. Use ":tnext" to jump to the next matching tag.

    It is possible to add help files for plugins and other items.  You don't need
    to change the distributed help files for that.  See |add-local-help|.

    To write a local help file, see |write-local-help|.

    Note that the title lines from the local help files are automagically added to
    the "LOCAL ADDITIONS" section in the "help.txt" help file |local-additions|.
    This is done when viewing the file in Vim, the file itself is not changed.  It
    is done by going through all help files and obtaining the first line of each
    file.  The files in $VIMRUNTIME/doc are skipped.

    							*help-xterm-window*
    If you want to have the help in another xterm window, you could use this
    command:
    	:!xterm -e vim +help &

    			*:helpfind* *:helpf*
    :helpf[ind]		Like |:help|, but use a dialog to enter the argument.
    			Only for backwards compatibility.  It now executes the
    			ToolBar.FindHelp menu entry instead of using a builtin
    			dialog.  {only when compiled with YXXY+GUI_GTK|}

    					*:helpt* *:helptags*

    				*E154* *E150* *E151* *E152* *E153* *E670*
    :helpt[ags] [++t] {dir}
    			Generate the help tags file(s) for directory {dir}.
    			When {dir} is ALL then all "doc" directories in
    			'runtimepath' will be used.

    			All "*.txt" and "*.??x" files in the directory and
    			sub-directories are scanned for a help tag definition
    			in between stars.  The "*.??x" files are for
    			translated docs, they generate the "tags-??" file, see
    			|help-translated|.  The generated tags files are
    			sorted.
    			When there are duplicates an error message is given.
    			An existing tags file is silently overwritten.

    			The optional "++t" argument forces adding the
    			"help-tags" tag.  This is also done when the {dir} is
    			equal to $VIMRUNTIME/doc.

    			To rebuild the help tags in the runtime directory
    			(requires write permission there):
    				:helptags $VIMRUNTIME/doc

    ==============================================================================

    2. Translated help files				*help-translated*

    It is possible to add translated help files, next to the original English help
    files.  Vim will search for all help in "doc" directories in 'runtimepath'.
    This is only available when compiled with the |+multi_lang| feature.

    At this moment translations are available for:
    	Chinese  - multiple authors
    	French   - translated by David Blanchet
    	Italian  - translated by Antonio Colombo
    	Japanese - multiple authors
    	Polish   - translated by Mikolaj Machowski
    	Russian  - translated by Vassily Ragosin
     See the Vim website to find them:	http://www.vim.org/translations.php

    A set of translated help files consists of these files:

    	help.abx
    	howto.abx
    	...
    	tags-ab

    "ab" is the two-letter language code.  Thus for Italian the names are:

    	help.itx
    	howto.itx
    	...
    	tags-it

    The 'helplang' option can be set to the preferred language(s).  The default is
    set according to the environment.  Vim will first try to find a matching tag
    in the preferred language(s).  English is used when it cannot be found.

    To find a tag in a specific language, append "@ab" to a tag, where "ab" is the
    two-letter language code.  Example:
    	:he user-manual@it
    	:he user-manual@en
    The first one finds the Italian user manual, even when 'helplang' is empty.
    The second one finds the English user manual, even when 'helplang' is set to
    "it".

    When using command-line completion for the ":help" command, the "@en"
    extension is only shown when a tag exists for multiple languages.  When the
    tag only exists for English "@en" is omitted.  When the first candidate has an
    "@ab" extension and it matches the first language in 'helplang' "@ab" is also
    omitted.

    When using |CTRL-]| or ":help!" in a non-English help file Vim will try to
    find the tag in the same language.  If not found then 'helplang' will be used
    to select a language.

    Help files must use latin1 or utf-8 encoding.  Vim assumes the encoding is
    utf-8 when finding non-ASCII characters in the first line.  Thus you must
    translate the header with "For Vim version".

    The same encoding must be used for the help files of one language in one
    directory.  You can use a different encoding for different languages and use
    a different encoding for help files of the same language but in a different
    directory.

    Hints for translators:
    - Do not translate the tags.  This makes it possible to use 'helplang' to
      specify the preferred language.  You may add new tags in your language.
    - When you do not translate a part of a file, add tags to the English version,
    using the "tag@en" notation.
    - Make a package with all the files and the tags file available for download.
      Users can drop it in one of the "doc" directories and start use it.
      Report this to Bram, so that he can add a link on www.vim.org.
    - Use the |:helptags| command to generate the tags files.  It will find all
      languages in the specified directory.

    ==============================================================================

    3. Writing help files					*help-writing*

    For ease of use, a Vim help file for a plugin should follow the format of the
    standard Vim help files.  If you are writing a new help file it's best to copy
    one of the existing files and use it as a template.

    The first line in a help file should have the following format:

    *helpfile_name.txt*	For Vim version 7.3	Last change: 2010 June 4

    The first field is a link to the help file name.  The second field describes
    the applicable Vim version.  The last field specifies the last modification
    date of the file.  Each field is separated by a tab.

    At the bottom of the help file, place a Vim modeline to set the 'textwidth'
    and 'tabstop' options and the 'filetype' to "help".  Never set a global option
    in such a modeline, that can have consequences undesired by whoever reads that
    help.

    TAGS

    To define a help tag, place the name between asterisks (*tag-name*).  The
    tag-name should be different from all the Vim help tag names and ideally
    should begin with the name of the Vim plugin.  The tag name is usually right
    aligned on a line.

    When referring to an existing help tag and to create a hot-link, place the
    name between two bars (|) eg. |help-writing|.|||

    When referring to a Vim command and to create a hot-link, place the
    name between two backticks, eg. inside `:filetype`.  You will see this is
    highlighted as a command, like a code block (see below).

    When referring to a Vim option in the help file, place the option name between
    two single quotes, eg. 'statusline'

    HIGHLIGHTING

    To define a column heading, use a tilde character at the end of the line.
    This will highlight the column heading in a different color.  E.g.

    Column heading

    To separate sections in a help file, place a series of '=' characters in a
    line starting from the first column.  The section separator line is highlighted
    differently.

    To quote a block of ex-commands verbatim, place a greater than (>) character
    at the end of the line before the block and a less than (<) character as the
    first non-blank on a line following the block.  Any line starting in column 1
    also implicitly stops the block of ex-commands before it.  E.g.
        function Example_Func()
    	echo "Example"
        endfunction

    The following are highlighted differently in a Vim help file:
      - a special key name expressed either in <> notation as in <PageDown>, or
        as a Ctrl character as in CTRL-X
      - anything between {braces}, e.g. {lhs} and {rhs}

    The word "Note", "Notes" and similar automagically receive distinctive
    highlighting.  So do these:
    	*Todo	something to do
    	*Error	something wrong

    You can find the details in $VIMRUNTIME/syntax/help.vim

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