tobin and binto is a pair of utilities to produce and parse binary data from the command line, mostly compatible with the Python "struct" module. Example:

./tobin ">bH6s" 4 0x70ff hejsan | ./binto ">bH6s"

This example produces binary output in big-endian order with a byte, an unsigned 16-bit word and a 6-byte string to stdout. The binto tool then parses this ouput and produces a human-readable output on stdout.