How to write a binary file using Bash?

Question

My problem is that I need to create a file with this exact bytes: 48, 00, 49, 00.

I cannot use C, perl, other scripting language (the target is an embedded

Answer 1

you could try echo, that also allows arbitrary ascii chars (those numbers are octal numbers).

echo -n -e \\0060\\0000\\0061\\0000  | hexdump