Hello, it's not the first time I'm having this problem and its really bugging me. Whenever I open a pipe using the Python subprocess module, I can only communicate with it once, as the documentation specifies: Read data from stdout and stderr, until end-of-file is reached

proc = sub.Popen("psql -h darwin -d main_db".split(),stdin=sub.PIPE,stdout=sub.PIPE)
print proc.communicate("select a,b,result from experiment_1412;\n")[0]
print proc.communicate("select theta,zeta,result from experiment_2099\n")[0]

The problem here is that the second time, Python isn't happy. Indeed, he decided to close the file after the first communicate:

Traceback (most recent call last):
File "a.py", line 30, in <module>
    print proc.communicate("select theta,zeta,result from experiment_2099\n")[0]
File "/usr/lib64/python2.5/subprocess.py", line 667, in communicate
    return self._communicate(input)
File "/usr/lib64/python2.5/subprocess.py", line 1124, in _communicate
     self.stdin.flush()
ValueError: I/O operation on closed file

So... multiple communications aren't allowed? I hope not ;)

Please enlighten me.