Python function to create a hexdump inspired by old DOS DEBUG command

prettybin.py

_fmtinner = ('',' ') * 3 + ('','-') + ('',' ') * 3 + ('','')
_fmtouter = ('  ', '  |', '|')

def _mkhex(d, i):
   try:
      return '%02x' % (ord(d[i]),)
   except IndexError:
      return '  '

def _mkchar(d, i):
   try:
      c = d[i]
      if 31 < ord(c) < 127:
         return c
      else:
         return '.'
   except IndexError:
      return ' '

# n is the number of digits in the address field, minimum is two.
# length of each line is 63, for n<3, then one more character for each n>=3
def prettify_binary(data, n=None):

   inputsize = len(data)
   if not n:
      n = ln2(max(0, inputsize-1), 4)

   lines, rmdr = divmod(inputsize, 16)
   if rmdr:
      lines += 1

   return '\n'.join([''.join(kk) for kk in [sum(zip(k, _fmtouter),()) for k in [
      [
         '%%0%dx0' % (n-1,) % (i,),

         ''.join(sum(zip([_mkhex(data, 16*i+j) for j in range(16)], _fmtinner), ())),

         ''.join([_mkchar(data, 16*i+j) for j in range(16)])

      ] for i in range(lines)] ]])


if __name__ == '__main__':
   import sys
   print prettify_binary(sys.stdin.read())

This is a dependency:
https://gist.github.com/sfaleron/1f958c6e37f4f235d5c8