Prints a formatted hexdump of a binary string

hexdump.py

#!/usr/bin/python
"""CLI USAGE: hexdump [-w n] [-ws b] <filename>

    -w  --words      the number of words to display on a line
    -ws --word-size  the number of bytes to display in a word
"""
import __future__
from StringIO import StringIO
import math

def hexdump(stream, words=4, word_size=4):
    use_stream = stream
    if isinstance(stream, (str, buffer)):
        use_stream = StringIO(stream)

    line_len = words * word_size
    cuts = int(math.ceil(line_len / float(word_size)))

    data = use_stream.read(line_len)

    while data:
        hexa = " ".join(["{:02x}".format(ord(char)) for char in data])
        ascii = "".join([char if ord(char) > 32 and ord(char) < 127 else '.' for char in data])
        
        # add spaces to deliniate words
        hexa = hexa.ljust(line_len * 3) # pad with whitespace
        hexa = " ".join([hexa[cut*3*word_size:(cut+1)*3*word_size] for cut in range(cuts)])
        ascii = ascii.ljust(line_len) # pad with whitespace
        ascii = " ".join([ascii[cut*word_size:(cut+1)*word_size] for cut in range(cuts)])

        print("| {} | {} |".format(hexa, ascii))

        data = use_stream.read(line_len)

if __name__ == "__main__":
    import sys

    if len(sys.argv) <= 1:
        print __doc__
    else:
        words = 4
        word_size = 4

        for i, val in enumerate(sys.argv):
            if val == "-w" or val == "--words":
                words = int(sys.argv[i+1])
            elif val == "-ws" or val == "--word-size":
                word_size = int(sys.argv[i+1])
        
        hexdump(open(sys.argv[-1]), words, word_size)