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

I needed to write binary files from hex using busybox within an old Android shell. This printf with a redirect worked in my use case.

Write the binary data in hex:

# busybox printf '\x74\x65\x73\x74' > /sdcard/test.txt

Display the result in hex:

# busybox hexdump -C /sdcard/test.txt
00000000  74 65 73 74                                       |test|
00000004

Display the result in ascii:

# cat /sdcard/test.txt
test