Tool for creating binary files from a text file of hexadecimal numbers
cat a.txt
90 80 10 2B
AA FF FF FF
90 F9 87 02
00 06 F2 C0
./binarymaker a.txt b
hexdump b
0000000 8090 2b10 ffaa ffff f990 0287 0600 c0f2
0000010
note that the hexdump result may have digits swapped due to endianness, the binary file is normal