How can I change a file's encoding with vim?

I'm used to using vim to modify a file's line endings:

$ file file
file: ASCII text, with CRLF line terminators
$ vim file
:set ff=mac
:wq
$ file file
file: ASCII text, with CR line terminators

Is it possible to use a similar process to change a file's unicode encoding? I'm trying the following, which doesn't work:

$ file file.xml
file.xml: Unicode text, UTF-16, little-endian
$ vim file
:set encoding=utf-8
:wq
$ file file.xml
file.xml: Unicode text, UTF-16, little-endian

I saw someone say that he could "set fileencoding=utf-8, then update and write the file, and it works," but I seem to be missing something, or else he was confused. I don't know what he meant by "then update."

Solution 1:

From the doc:

:write ++enc=utf-8 russian.txt

So you should be able to change the encoding as part of the write command.

Solution 2:

Notice that there is a difference between

set encoding

and

set fileencoding

In the first case, you'll change the output encoding that is shown in the terminal. In the second case, you'll change the output encoding of the file that is written.

Solution 3:

While using vim to do it is perfectly possible, why don't you simply use iconv? I mean - loading text editor just to do encoding conversion seems like using too big hammer for too small nail.

Just:

iconv -f utf-16 -t utf-8 file.xml > file.utf8.xml

And you're done.