Converting a string into Unsigned int 8 array

Question

I am new to bash and I am trying to convert a swift obfuscation into a bash script.

Basically, I want to convert a string into an Unsigned-Int 8 array (UTF-8).

For example,

"hey" = [104, 101, 121] (UTF-8 UINT8 value)
"example" = [101, 120, 97, 109, 112, 108, 101] (UTF-8 UINT8 value)

Does anyone know if this is possible?

Answer 1

The following shell script converts input in the for of hey into the string [104, 101, 121].

# Print hey
printf "%s" hey |
# convert to hex one per line
xxd -p -c 1 |
# convert to decimal one per line
xargs -I{} printf "%d\n" 0x{} |
# Join lines with comma
paste -sd, |
# Add spaces after comma
sed 's/,/, /g' |
# Add [ ]
{ echo -n '['; tr -d '\n'; echo ']'; }
# echo "[$(cat)]"

The script is not aware of input encoding - the script only translates bytes representation. The input string has to be already in the desired encoding. Use iconv to convert between encodings.

edit: it looks pretty inefficient, I would do:

$ printf "%s" hey | xxd -p -c 1 | { printf "["; xargs -I{} printf "%d, " 0x{} | sed 's/, $//'; printf "]\n"; }
[104, 101, 121]

Or in pure bash should be even faster:

string=hey
output=""
for ((i=0;i<${#string};i++)); do
     printf -v output "%s%d" "$output${output:+, }" "'${string:i:1}"
done
echo "[$output]";
# outputs: [104, 101, 121]