Print the output of a command line command in hexdump format

consoledump.py

#!/usr/bin/env python

import sys
import pty
import os
import subprocess
import string

"""
An example script to show how Python's pty module can be used to capture the
input of any console program. This script prints out each byte from its
subprocess in hexdump format. It's useful for debugging console interfaces that
have lots of control characters.

"""

printable = set(string.printable) - set(string.whitespace) | set(" ")
chrmap = {
        '\x1b': '^',
        '\n': '\\n',
        '\r': '\\r',
        '\t': '\\t',
        "\x01": u"\N{BLACK STAR}".encode("UTF-8"),
        "\x02": u"\N{WHITE STAR}".encode("UTF-8"),
        }

# line is the most recently written line to the console
line = ""
def printhex(char):
    global line
    if len(line) == 16:
        sys.stdout.write("\n")
        line = ""
    line += char
    sys.stdout.write("\r")
    for c in line[:8]:
        sys.stdout.write("%02X " % ord(c))
    sys.stdout.write("  ")
    for c in line[8:16]:
        sys.stdout.write("%02X " % ord(c))
    sys.stdout.write("     ")
    sys.stdout.write(" " * 3*(16-len(line)))
    for c in line:
        if c in printable:
            sys.stdout.write(c)
        elif c in chrmap:
            sys.stdout.write(chrmap[c])
        else:
            sys.stdout.write(u"?".encode("UTF-8"))
    sys.stdout.flush()


def main():

    path = sys.argv[1]
    arglist = sys.argv[2:]

    master, slave = pty.openpty()

    proc = subprocess.Popen([path]+arglist,
            stdout=slave, stderr=slave)
    os.close(slave)

    while not proc.poll():
        try:
            a = os.read(master, 1)
        except OSError:
            break
        except KeyboardInterrupt:
            continue
        if not a: break
        printhex(a)
    print

if __name__ == "__main__":
    main()