The recode reference manual
5.6 Frequency count of characters
A device may be used to obtain a list of characters in a file, and how many
times each character appears. Each count is followed by the UCS-2
value of the character and, when known, the RFC 1345 mnemonic for that
character.
This charset is available in recode under the name
count-characters.
This count feature has been implemented as a charset. This may
change in some later version, as it would sometimes be convenient to count
original bytes, instead of their UCS-2 equivalent.
