python - pytee can not produce proper output in python3 -

i have piece of code runs in python 2.7.5 doesn't work python 3.

the major problem tee.write, can not write file.

this piece of code suppose write 20 letters a file /tmp/tee-test-1 , /tmp/tee-test-2 not, 2 files empty…

could 1 give me advice?

import sys import os import subprocess #from  netsa.util.shell import * string import template  __author__ = 'brandon sandrowicz <brandon@sandrowicz.org>' __version__ = '0.1'  valid_modes = ['a','w']  def create_tee(files, mode, buffer_size=128):           if mode not in valid_modes:             raise ioerror("only valid modes create_tee() are: %s" % ', '.join(valid_modes))          tee_list = []         file in files:             if type(file) == str:                 fp = open(file, mode)                 tee_list.append(fp)             else:                 tee_list.append(file)          pipe_read, pipe_write = os.pipe()         pid = os.fork()         if pid == 0:             # child -- read bytes pipe , write them specified             # files.             try:                 # close parent's end of pipe                 os.close(pipe_write)                  bytes = os.read(pipe_read, buffer_size)                 print (bytes)                 while(bytes):                     file in tee_list:                         file.write(bytes)                         file.flush()                         # todo maybe add in fsync() here if fileno() method                         # exists on file                      bytes = os.read(pipe_read, buffer_size)             except:                 pass             finally:                 os._exit(255)         else:             # parent -- return file object wrapper around pipe             # child.             return os.fdopen(pipe_write,'w')    if __name__ == '__main__':      files = [ '/tmp/tee-test-1', '/tmp/tee-test-2' ]     num_chars = 100000      print("writing %d chars files (using create_tee):" % num_chars)     file in files:         print(" %s" % file)     print()      tee = create_tee(files,mode='a')     #print("a" * num_chars, end=' ', file=tee)     tee.write("a" * 20)     tee.close()     os.wait()      filename in files:         open(filename, 'r') fh:             chars = len(fh.read())             print("file '%s' has %d chars" % (filename, chars)) 

ok, found problem interesting , challenging, , found out what's wrong, it's said in that document:

one common problem file opened in wrong mode. make sure open text files 't' flag , binary files 'b' flag , have solved many problems.

so you're writing data b"" datatype, tried following:

    file in files:         if type(file) == str:             fp = open(file, mode+'b')             tee_list.append(fp)         else:             tee_list.append(file) 

and works well:

file '/tmp/tee-test-1' has 20 chars file '/tmp/tee-test-2' has 20 chars