Convert Decimals to Hexadecimals and backwards in Shell

d2h.sh

#!/bin/bash

# convert decimal (0-255) to hexadecimal (00-FF)
function d2h() { printf "%X\n" $1 }

h2d.sh

#!/bin/bash

# convert hexadecimal (00-FF) to decimal (0-255)
# don't forget to prepend "0x"
function h2d() { printf "%d\n" $1 }