Script en Bash hexadecimal a texto - Hexadecimal to text in bash

Input: "data.txt" debe tener formato de a 2 caracteres separados por un enter, por ejemplo:

data.txt:
48 4f 4c 41

Output: "result.txt" tendrá el formato de letras separadas por un enter, por ejemplo la salida del imput previo será:

result.txt:
HOLA


Código en Bash:

#!/bin/bash
for line in $(cat data.txt); do
case $line in
"20") echo -n " " >> ./result.txt
;;
"41") echo -n "A" >> ./result.txt
;;
"42") echo -n "B" >> ./result.txt
;;
"43") echo -n "C" >> ./result.txt
;;
"44") echo -n "D" >> ./result.txt
;;
"45") echo -n "E" >> ./result.txt
;;
"46") echo -n "F" >> ./result.txt
;;
"47") echo -n "G" >> ./result.txt
;;
"48") echo -n "H" >> ./result.txt
;;
"49") echo -n "I" >> ./result.txt
;;
"4a") echo -n "J" >> ./result.txt
;;
"4b") echo -n "K" >> ./result.txt
;;
"4c") echo -n "L" >> ./result.txt
;;
"4d") echo -n "M" >> ./result.txt
;;
"4e") echo -n "N" >> ./result.txt
;;
"4f") echo -n "O" >> ./result.txt
;;
"50") echo -n "P" >> ./result.txt
;;
"51") echo -n "Q" >> ./result.txt
;;
"52") echo -n "R" >> ./result.txt
;;
"53") echo -n "S" >> ./result.txt
;;
"54") echo -n "T" >> ./result.txt
;;
"55") echo -n "U" >> ./result.txt
;;
"56") echo -n "V" >> ./result.txt
;;
"57") echo -n "W" >> ./result.txt
;;
"58") echo -n "X" >> ./result.txt
;;
"59") echo -n "Y" >> ./result.txt
;;
"5a") echo -n "Z" >> ./result.txt
;;
"61")
echo -n "a" >> ./result.txt
;;
"62")
echo -n "b" >> ./result.txt
;;
"63")
echo -n "c" >> ./result.txt
;;
"64")
echo -n "d" >> ./result.txt
;;
"65")
echo -n "e" >> ./result.txt
;;
"66")
echo -n "f" >> ./result.txt
;;
"67")
echo -n "g" >> ./result.txt
;;
"68")
echo -n "h" >> ./result.txt
;;
"69")
echo -n "i" >> ./result.txt
;;
"6a")
echo -n "j" >> ./result.txt
;;
"6b")
echo -n "k" >> ./result.txt
;;
"6c")
echo -n "l" >> ./result.txt
;;
"6d")
echo -n "m" >> ./result.txt
;;
"6e")
echo -n "n" >> ./result.txt
;;
"6f")
echo -n "o" >> ./result.txt
;;
"70")
echo -n "p" >> ./result.txt
;;
"71")
echo -n "q" >> ./result.txt
;;
"72")
echo -n "r" >> ./result.txt
;;
"73")
echo -n "s" >> ./result.txt
;;
"74")
echo -n "t" >> ./result.txt
;;
"75")
echo -n "u" >> ./result.txt
;;
"76")
echo -n "v" >> ./result.txt
;;
"77")
echo -n "w" >> ./result.txt
;;
"78")
echo -n "x" >> ./result.txt
;;
"79")
echo -n "y" >> ./result.txt
;;
"7a")
echo -n "z" >> ./result.txt
;;
*)
echo -n "Valor no encontrado"
;;
esac
done
echo >> ./result.txt