[Tutor] Single Backslash (was 'DOS Commands?')

[Magnus Lycka]

Hi James!

There's a tiny bug left. Hope it'll work once that's
fixed.

At 11:09 2002-11-11 +0000, James.Rocks@equant.com wrote:
>      popen(sDOSCommand, 'w').readlines()

This should be
       popen(sDOSCommand).readlines()

Just skip the 'w'. You *read* from the file descriptor,
right? So why do you open it with 'w'?

The 'w', 'r' flags have nothing to do with the
content of your "DOS" command if that's what you
think. They have everything to do with how you
use the file descriptor in Python. This one you
read from with the readlines() method. That means
you must use 'r' (which is the default).

See:
 >>> print os.popen('dir', 'w').read()
Traceback (most recent call last):
   File "<interactive input>", line 1, in ?
IOError: [Errno 9] Bad file descriptor
 >>> print os.popen('dir').read()
.........


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Magnus Lycka, Thinkware AB
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