# Hex encoder and decoder

# cat hexcoder.sh 
#!/bin/bash

function decode {
    echo -n "$1" | sed 's/%\(..\)/\1/g' | xxd -p -r
    echo
}

function encode {
    echo -n "$1" | xxd -p | tr -d '\n' | sed 's/\(..\)/%\1/g'
    echo
}

case $1 in
    "-d") decode $2;;
    "-e") encode $2;;
esac
# ./hexcoder.sh -e hacktracking
%68%61%63%6b%74%72%61%63%6b%69%6e%67
# ./hexcoder.sh -d %68%61%63%6b%74%72%61%63%6b%69%6e%67
hacktracking