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created 2006 · complexity basic · author Tony Mechelynck · version 6.0

Usually, when opening an editfile while 'encoding' is set to UTF-8, Vim will try UTF-8 before Latin1. This is all good and proper since the UTF-8 heuristic can give an error result and the Latin1 one cannot. However, if the file contains (at the moment) only 7-bit ASCII data, it will be represented identically under Latin1 and UTF-8, and no one (not even a human) can decide without additional information.

If we want later-added bytes above 127 to be represented as Unicode, the solution is simple: we can add a BOM to the file by setting the 'bomb' option (":setlocal bomb"). But what if we want later data between 128 and 255 to be represented as Latin1? This is a little trickier, but the answer is simple; it's of the kind that makes one say "Now why didn't I think of that?". Here it is:

  • If you want your file to be always interpreted by Vim as Latin1 and never as UTF-8, place in it a line with a number of "upper-ASCII" bytes in it (i.e. bytes in the range 128-255), then save the file after making sure that 'fileencoding' is set to Latin1, e.g. by doing ":setlocal fenc=latin1". In a program source file or a shell script, the line can be a comment; in a text file, it can be "fancy underlining". The following will do (for example):
    # zim: set fenc=latin1 nomod : ÷÷÷÷÷÷

Place it where you would a modeline. Notice that with the letter v instead of z in column 3 it would be a modeline; but the problem with setting the 'fileencoding' by means of a modeline is that the latter's action happens only after the file has been read. This line will make the "typical" 'fileencodings' heuristics (as set, e.g., by ":set fileencodings=ucs-bom,utf-8,latin1") to give a "negative" result for UTF-8, so that Vim's automatic mechanisms will recognise the file as Latin1.

See also Working with Unicode.


If the purpose is to ensure the loader fails to match it UTF-8, why not just put something like #£ in the file. Why bother with the pseudo-modeline?

You could. One possible way is to use Latin1 "divide-by signs" to underline the top title. It all depends what you want the file to look like. You may also want to make sure that none of your co-editors (if any) remove the upper-ASCII bytes, and that may require a comment. -- Tonymec 15:48, 29 November 2007 (UTC)

To force opening a file in Latin1 I just call vim this way:

$ vim --cmd "set encoding=Latin1" file.txt

-- Cocker68 2011-08-19 23:35:10 (UTC+2)

This is a bad idea, it sets Vim's internal encoding to Latin1. Most people using a Vim with encoding utf-8 are doing so intentionally and would not want Vim to internally use Latin1. You will then be unable to view any characters not in Latin1 inside Vim.

The correct way to do this from the command-line, if you know in advance that the file is Latin1, is something like this:

$ vim -c "e ++enc=latin1" file.txt

However, the entire point of this tip, is that one does not NEED to remember to specify on the command-line whenever editing a pure latin1 file.

--Fritzophrenic 22:32, August 19, 2011 (UTC)