freq - print histogram of character frequencies
freq [ -dxocr ] [ file ... ]
Freq reads the given files (default standard input) and prints histograms
of the character frequencies. By default, freq counts each byte as a
character; under the -r option it instead counts UTF
sequences, that is, runes.
Each non-zero entry of the table is printed preceded by the byte
value, in decimal, octal, hex, and Unicode character (if printable). If any
options are given, the -d, -x, -o, -c flags
specify a subset of value formats: decimal, hex, octal, and character,
respectively.