Calculating the character distribution of common unix commands, builtins, and keywords

results.txt

!	1
:	1
K	1
O	1
{	1
}	1
7	2
E	2
G	2
H	2
I	2
L	2
T	2
]	2
6	3
B	3
F	3
N	3
W	3
9	4
P	4
[	4
A	5
D	5
U	6
4	7
C	7
+	8
M	8
R	9
S	10
3	11
j	13
q	29
z	51
2	58
_	60
-	77
1	77
8	79
w	80
5	81
v	85
x	94
y	106
.	127
k	131
b	161
h	186
g	201
f	235
u	279
m	293
n	432
c	451
r	451
l	460
d	472
i	516
a	529
o	532
p	593
s	660
t	662
e	710

script.sh

#!/usr/bin/env bash

declare -A alph
dirs=( 
	/usr/local/bin
	/usr/bin
	/bin
	/usr/sbin
	/sbin
)

for c in $(compgen -bk); do 
	for ((i=0; i<${#c}; i++)); do
		p=${c:$i:1}
		alph[$p]=$((${alph[$p]} + 1))
	done
done

for dir in "${dirs[@]}"; do
	commands=( $(find "$dir" -type f -exec basename {} \;) )
	for c in "${commands[@]}"; do
		for ((i=0; i<${#c}; i++)); do
			p=${c:$i:1}
			alph[$p]=$((${alph[$p]} + 1))
		done
	done
done

for i in "${!alph[@]}"; do
	printf '%s\t%s\n' "$i" "${alph[$i]}"
done | sort -nk2,2