Am I correct that what my OS is telling me is its best guess as to how to interpret this file and have it make any sense?

Yes, with the emphasis being that it's just a guess.

the OS thinks the doc is utf8 if there are utf8 non-ascii characters in it.

Yes, and it might be important to note that there are certain sequences of bytes that are not valid UTF-8 (see e.g. UTF-8), which means that in some cases, it's possible to differentiate between random bytes and valid UTF-8 text. Also, just to nitpick a little, it's not the OS guessing the file's encoding, it's the file tool.

I did nothing with the #.haukex scripts to change from us-ascii to utf8 but begin to include cyrillic characters

Note that if you have a file that is originally ASCII and you add non-ASCII characters to it, it's up to the editor to choose which encoding it will use when saving the file. Many editors will default to UTF-8, but some may not!

with pre tags

You may have noticed that when using <pre> tags, you have to escape square brackets, [ is &#91; and ] is &#93;.

Update: Improved wording of first paragraph.

In reply to Re^3: create clone script for utf8 encoding by haukex
in thread create clone script for utf8 encoding by Aldebaran

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