You can use
b N Value of character under cursor.
B N As above, in hexadecimal.
set statusline=%b\ 0x%B
Another way is to use
ga or the
:ascii command. From
: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
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).