#!/usr/bin/env python3

# usage:
#   hex.py file1 file2
#   cat file1 | hex.py

import os, sys

if len(sys.argv) > 1:
	for fn in sys.argv[1:]:
		print(fn)
		with open(fn, 'rb') as f:
			print(f.read().hex(' ', 1))
	exit()

hasmore = True
while hasmore:
	# os.read returns a bytes object
	# sys.stdin returns a str object
	
	# read one byte from file descriptor 0 (stdin)
	b = os.read(0,1)
	if b == b'':
		print('')
		exit()
	print(b.hex(), end=' ')