[IPython-dev] A couple of odd behaviours...

[Carl Smith]

On reflection, I think I may have caused stdout to go to the terminal
the one time I saw that it had, by messing around trying to fix
things. I'm really unsure on that one now. I may have been playing
with os.system at the time.

None of this is a massive problem for me as it stands. I'll probably
want to return the output of all adb shell commands anyway. I've made
my Android object callable, with it's args being the adb shell
commands, so I can just do `a = droid('ls')`. It's pure curiosity
that's got me now.

On 8 November 2012 16:03, Carl Smith <carl.input at gmail.com> wrote:
> I don't have anything in config or startup files at all. I was using
> nbcloud for ages, and reformatted this machine not so long back, so my
> local Notebook installation is brand new. I'm still using the default
> config IPython created for me, and have nothing in startup.
>
> I'm not sure how to check ip.system is ip.system_piped, but tried the
> following with the same result.
>
> ip = get_ipython()
> ip.system = ip.system_piped
> !adb shell ls
>
> I've noticed that it doesn't always print everything to the terminal.
> It seems to do it sometimes and not others, so I need to figure out
> what's causing the change and maybe work it out from there.
>
> If I do `ip.system = ip.system_raw`, then it always goes to the
> terminal, so that works. If I do `ip.system = ip.system_piped` it goes
> bank to printing blank lines, with nothing in the terminal. Because
> the printing to the terminal thing is happening on and off, well, I've
> only seen it happen once, I need to find out why. It can't literally
> be random.
>
> I did just try creating a new directory on my main machine, then
> launching the Notebook from that empty directory, then just running
> `!adb shell ls` in a new notebook. Same problem. I also tried running
> the three lines above to explicitly demand that my output gets piped,
> but to no avail.
>
> I tried using os.system, which sends stdout to the terminal, and
> ip.system, which prints blank lines.
>
> P.S. Why does ip.system return None? Shouldn't it return an int?
>
> On 8 November 2012 14:23, Thomas Kluyver <takowl at gmail.com> wrote:
>> On 8 November 2012 02:42, Carl Smith <carl.input at gmail.com> wrote:
>>>
>>> I tried `pwd` and so on, and get the same behaviour. Everything
>>> printed by `!abd shell <cmd>` ends up in the terminal, not in the
>>> Notebook, though I still get a newline in the Notebook for each line
>>> that should be there.
>>>
>>> Any thoughts?
>>
>>
>> You don't have anything in config or startup files that could be setting
>> ip.system to ip.system_raw? Can you check that ip.system is ip.system_piped,
>> just before an offending command?
>>
>> We fail to redirect C-level stdout from within the kernel process (issue
>> #1230), but the subprocess when you run a system command should be run in a
>> new pseudoterminal controlled by IPython, so I'm mystified why the output is
>> going to the wrong place.
>>
>> Thomas
>>
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