How to save a character with a line above (like this ō) in a file system?

Question

What file format should I use? It is for PHP to afterwards retrieve such a character and for HTML to display.

Answer 1

You should be encoding the text as UTF8, then writing it to the file.

If you're doing this with PHP, then (I think) it'll be something like:

$f = fopen("/path/to/file", "w");
fwrite($f, utf8_encode($some_string));
fclose($f);

(although, this assumes that PHP is using Unicode internally… But, then, it might not – my memory is kind of hazy)