Is subprocess.Popen completely broken?

[Skip Montanaro]

I am trying to replace os.system calls with subprocess.Popen.  This simple
example fails miserably:

>>> proc = subprocess.Popen ("ls /tmp")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/titan/skipm/local/lib/python2.5/subprocess.py", line 594, in __init__
    errread, errwrite)
  File "/home/titan/skipm/local/lib/python2.5/subprocess.py", line 1091, in
_execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

I also tried explicitly referencing /usr/bin/ls.  Same result.  What gives?
I see this behavior in both Python 2.4 and 2.5 on Solaris 10 and with
2.6alpha on Mac OS X.

Frustrated in Chicago...

Skip