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The modeline cannot be anywhere in the file: it must be in the first or last few lines. The exact location where vim checks for the modeline is controlled by the <code>modelines</code> variable; see {{help|'modelines'}}. By default, it is set to 5 lines.
 
The modeline cannot be anywhere in the file: it must be in the first or last few lines. The exact location where vim checks for the modeline is controlled by the <code>modelines</code> variable; see {{help|'modelines'}}. By default, it is set to 5 lines.
 
In a Python file, the '<code>#</code>' starts a comment so the modeline is not interpreted by Python.
 
   
 
The following examples show some alternatives that could be in a C file:
 
The following examples show some alternatives that could be in a C file:
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vim:ff=unix ts=4 ss=4
 
vim:ff=unix ts=4 ss=4
 
vim60:fdm=marker
 
vim60:fdm=marker
  +
</pre>
  +
  +
==Enabling modelines==
  +
Vim executes a modeline only if all of the following apply:
  +
*'modeline' is set to "modeline" (not "nomodeline")
  +
*'modelines' is set to a positive integer (not "0")
  +
*You are not root.
  +
  +
Enter the following to see the current settings and, if not the default, where they were last set.
  +
<pre>
  +
:verbose set modeline? modelines?
  +
</pre>
  +
  +
Debian, Ubuntu, Gentoo, OSX, etc. by default disable modelines for security reasons. To enable modelines, edit your vimrc file (for example, in Vim enter <code>:e $MYVIMRC</code>) and check you have lines like the following.
  +
<pre>
  +
set modeline
  +
set modelines=5
 
</pre>
 
</pre>
   
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See {{script|id=1876}} - securemodelines
 
See {{script|id=1876}} - securemodelines
 
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How can we make this page more discoverable? New users may have seen a comment at the top of a file, with vim settings in it, but they don't know that this is called a 'modeline'. They may search for something like ''"set options in a comment"'' and we should return this page. <small>--Preceding [[Vim Tips Wiki:Quick reference|unsigned]] comment added by [[User:Chopp3r|Chopp3r]] 00:19, November 26, 2013</small>
 
:I made a redirect, see [[Set options in a comment]]. Clicking that link will go to this page, and at the top will be a small link saying "(Redirected from [http://vim.wikia.com/wiki/Set_options_in_a_comment?redirect=no Set options in a comment])". Clicking that will go to the actual redirect page, which you can edit to see the idea. The search engine takes some time (a day or two?) to update its indices, but after that searching for "set options in a comment" should go directly here. It should help Google find that as well. In practice it is difficult anticipating what people might search for, but your suggested text is very reasonable so a redirect is worthwhile. [[User:JohnBeckett|JohnBeckett]] ([[User talk:JohnBeckett|talk]]) 09:10, November 26, 2013 (UTC)
 
::I just tried "vim set options in a comment" (without quotes) in Google, and this page was #3, behind Stackoverflow at #1 and #2. It's hard to improve on #3, but we'll see what happens in a few days. [[User:JohnBeckett|JohnBeckett]] ([[User talk:JohnBeckett|talk]]) 09:12, November 26, 2013 (UTC)
 
   
  +
How is it that the modeline:
  +
<code>vim: noai:ts=4:sw=4</code>
  +
is used as an example of correct modeline usage and then used as an error example (when describing use of 'set') right afterwards?
  +
:Because, if you are using the <code>set:</code> syntax, then the modeline ends on the first <code>:</code> character it finds. Thus, you can include the modeline in <code>/* ... */</code> style comments. When you are *not* using the <code>set:</code> syntax, then the modeline always continues to the end of the line. Any text at all in the line will be considered part of the modeline. Therefore you cannot use <code>/* ... */</code> style comments, you must use <code>//</code> style comments. --[[User:Fritzophrenic|Fritzophrenic]] ([[User talk:Fritzophrenic|talk]]) 18:11, February 5, 2015 (UTC)
 
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Latest revision as of 00:38, February 9, 2015

Tip 331 Printable Monobook Previous Next

created 2002 · complexity basic · version 6.0


Options set in your vimrc will apply to all files that you edit. You can also set:

  • Different options for all files of a certain type (for example, all *.py files). See filetype.vim and filetypes and an example.
  • Different options for a particular file using modelines (this tip).

Note that the 'modeline' option must be set in order to take advantage of this tip. This option is set by default for Vim running in nocompatible mode, but some notable distributions of Vim disable this option in the system vimrc for security. In addition, it is off by default when editing as root. See :help 'modeline' for more information.

ExamplesEdit

For example, in a particular file you may want each tab character that you type to be expanded to spaces. To achieve this, put the following modeline near the top or the bottom of that file:

# vim: set expandtab:

The space between the comment opening and vim: is required, otherwise the modeline will not be recognized.

The modeline cannot be anywhere in the file: it must be in the first or last few lines. The exact location where vim checks for the modeline is controlled by the modelines variable; see :help 'modelines'. By default, it is set to 5 lines.

The following examples show some alternatives that could be in a C file:

// vim: noai:ts=4:sw=4
   -or-
/* vim: noai:ts=4:sw=4
*/
   -or-
/* vim: set noai ts=4 sw=4: */
   -or-
/* vim: set fdm=expr fde=getline(v\:lnum)=~'{'?'>1'\:'1': */

With "set", the modeline ends at the first colon not following a backslash. Without "set", no text can follow the options, so for example, the following is invalid:

Error E518: Unknown option: */
/* vim: noai:ts=4:sw=4 */

Adding a modelineEdit

With the following in your vimrc and the default leader key, you could type \ml to add a modeline based on your current settings:

" Append modeline after last line in buffer.
" Use substitute() instead of printf() to handle '%%s' modeline in LaTeX
" files.
function! AppendModeline()
  let l:modeline = printf(" vim: set ts=%d sw=%d tw=%d %set :",
        \ &tabstop, &shiftwidth, &textwidth, &expandtab ? '' : 'no')
  let l:modeline = substitute(&commentstring, "%s", l:modeline, "")
  call append(line("$"), l:modeline)
endfunction
nnoremap <silent> <Leader>ml :call AppendModeline()<CR>

In a C file, you would get a modeline like this:

/* vim: set ts=8 sw=4 tw=0 noet : */

Alternatively, you could use a simple menu entry, for example:

amenu Edit.Insert\ &modeline <C-\><C-N>ggOvim:ff=unix ts=4 ss=4<CR>vim60:fdm=marker<Esc>

Choosing the menu item would insert two modelines like this:

vim:ff=unix ts=4 ss=4
vim60:fdm=marker

Enabling modelinesEdit

Vim executes a modeline only if all of the following apply:

  • 'modeline' is set to "modeline" (not "nomodeline")
  • 'modelines' is set to a positive integer (not "0")
  • You are not root.

Enter the following to see the current settings and, if not the default, where they were last set.

:verbose set modeline? modelines?

Debian, Ubuntu, Gentoo, OSX, etc. by default disable modelines for security reasons. To enable modelines, edit your vimrc file (for example, in Vim enter :e $MYVIMRC) and check you have lines like the following.

set modeline
set modelines=5

SecurityEdit

 TO DO 

  • Need note on security implications of modelines and reference to alternatives.
  • Text other than "vim:" can be recognised as a modeline.
  • Google "vim modeline vulnerability" (without quotes) for information.

ReferencesEdit

CommentsEdit

This mechanism can be extended to 'let' – see script#83.

See script#1876 - securemodelines


How is it that the modeline: vim: noai:ts=4:sw=4 is used as an example of correct modeline usage and then used as an error example (when describing use of 'set') right afterwards?

Because, if you are using the set: syntax, then the modeline ends on the first : character it finds. Thus, you can include the modeline in /* ... */ style comments. When you are *not* using the set: syntax, then the modeline always continues to the end of the line. Any text at all in the line will be considered part of the modeline. Therefore you cannot use /* ... */ style comments, you must use // style comments. --Fritzophrenic (talk) 18:11, February 5, 2015 (UTC)

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