How to enter in any character in Vi / Vim

By character value Edit

It is also possible to enter any character (which can be displayed in your current 'encoding'), even a character for which no digraph is defined, if you know the character value, as follows (where ^V means "hit Ctrl-V, except if you use Ctrl-V to paste, in which case you should hit Ctrl-Q instead):

• By decimal value: ^Vnnn (with 000 <= nnn <= 255)
• By octal value: ^VOnnn or ^Vonnn (with 000 <= nnn <= 377)
• By hex value: ^VXnn or ^Vxnn (with 00 <= nn <= FF)
• By hex value for BMP Unicode codepoints: ^Vunnnn (with 0000 <= nnnn <= FFFF)
• By hex value for any Unicode codepoint: ^VUnnnnnnnn (with 00000000 <= nnnnnnnn <= 7FFFFFFF)

http://vim.wikia.com/wiki/Entering_special_characters