hist.awk

#!/usr/bin/awk -f

function strrep(n, c) {
	s = ""

	for (i = 0; i < n; i++) {
		s = c s
	}

	return s
}

{
	for (i = 1; i <= NF; i++) {
		a[$i]++
	}
}

END {
	for (k in a) {
		if (length(k) > max) {
			max = length(k)
		}
	}

	for (k in a) {
		if (length(sprintf("%u", max)) > width) {
			width = length(sprintf("%u", max))
		}
	}

	for (k in a) {
		printf("%-*s %*u %s\n", max, k, width, a[k], strrep(a[k], "▪"));
	}
}

A simple histogram that works the way I want.

; decomment life-utf8.c | ./hist.awk | grep '^[a-z]' | sort -rnk 2 | head -10
unsigned                 29 ▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪
static                   20 ▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪▪
y                         8 ▪▪▪▪▪▪▪▪
x                         8 ▪▪▪▪▪▪▪▪
void                      8 ▪▪▪▪▪▪▪▪
return                    8 ▪▪▪▪▪▪▪▪
y;                        7 ▪▪▪▪▪▪▪
x;                        6 ▪▪▪▪▪▪
sizeof                    6 ▪▪▪▪▪▪
y)                        5 ▪▪▪▪▪