bidirectional tee

tee.py

#!/usr/bin/python

import sys
import subprocess
import threading
import signal

if len(sys.argv) < 3:
    sys.stderr.write("Usage: {0} output_file command [arg [arg] ...]\n"\
                        .format(sys.argv[0]))
    sys.exit(1)

name = sys.argv[0]
filename = sys.argv[1]
command = sys.argv[2:]

l = open(filename, "a")
m = threading.Lock()
p = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE, 
                     stderr=subprocess.PIPE, bufsize=1)

l.write("{0} -- started {1}\n".format(p.pid, repr(command)))

def t(pfrom, pto, name):
    while True:
        line = pfrom.readline()
        if not line:
            break

        pto.write(line)
        pto.flush()
        with m:
            l.write(str(p.pid) + " " + name + " " + line)

    if pto == p.stdin:
        pto.close()

def s(*args):
    with m:
        l.write("{0} -- SIGINT\n".format(p.pid))
    p.send_signal(signal.SIGINT)

signal.signal(signal.SIGINT, s)

thr_in = threading.Thread(target=t, args=(sys.stdin, p.stdin, ">>"))
thr_out = threading.Thread(target=t, args=(p.stdout, sys.stdout, "<<"))
thr_err = threading.Thread(target=t, args=(p.stderr, sys.stderr, "!!"))

thr_in.daemon = True
thr_in.start()
thr_out.start()
thr_err.start()

r = p.wait()

thr_out.join()
thr_err.join()

m.acquire()
l.write("{0} -- exited: {1}\n".format(p.pid, r))

l.close()
sys.exit(r)