Q:

See the Unicode code point of the current character

How can I see the Unicode code point of the character where the cursor is? For example, if my cursor is on a ⌘ character, I'd like Vim to tell me that it is U+2318.
Alternative information, such as the base-10 representation (8984) or the UTF-8 representation (E2 8C 98) would be acceptable.
I ask about Unicode and UTF-8 because they are most common, but if the answer generalizes to other character sets and encodings, that would be good to know as well.

A:

You can use %b or %B in statusline or rulerformat. From :help statusline:
b N   Value of character under cursor. 
B N   As above, in hexadecimal. 

For example:
set statusline=%b\ 0x%B

Gives you:
8984 0x2318

Another way is to use ga or the :ascii command. From :help ga:
:as[cii]        or                                      ga :as :ascii
ga                      Print the ascii value of the character under the
                        cursor in decimal, hexadecimal and octal.

Which will give you:
<⌘> 8984, Hex 2318, Octal 21430

Another useful mapping is g8:
e2 8c 98

Which prints the hex value of the actual bytes stored in the file (this command assumes UTF-8).
In addition there are some plugins you could use:

unicode.vim adds various useful unicode-related commands. Use :UnicodeName to get details of the character under the cursor.
characterize.vim; this expands the ga command with the unicode name, similar to unicode.vim.
My own uni CLI tool has a little Vim integration script which provides :UnicodeName from unicode.vim (but none of the other features).

