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 device). I tried this using awk, and in desktop it does work:

# awk  'BEGIN{ printf "%c%c%c%c", 48, 00, 49, 00 }' | hexdump 0000000 0030 0031                               0000004 

However the target platform is running busybox v1.13.2 and this code does not work there. The awk version there does not output ascii "0" (all other values are ok).

What are your recommendations?

Answer 1

you can use the following command:

echo -n -e \\x48\\x00\\x49\\x00 > myfile 

Answer 2

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

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