The combination of installing Python 3.7 on RasPi and removing the
StringIO() cures the error.
I now get the statistics and the 'have a nice day' output from omxplayer.
I just need to find out how to invoke the idle 3.7, rather than idle
3.5, but I think that is a question for the RasPi forum.
I had not spotted that! It appears that, although I have 3.7 on my
laptop, 3.7 is not a part of the latest standard Raspbian release. I
will install this later today and try again.
Dave
On 03/12/2018 10:12, Alan Gauld via Tutor wrote:
On 02/12/2018 10:29, Dave Hill wrote:
Having 'graduated'
On 12/2/18 3:29 AM, Dave Hill wrote:
> Having 'graduated' to Python 3.7, I thought I would explore
> subprocess.Popen, and put the code in a Class, see code below. The video
> runs, but an error occurs, which I do not understand, see further below
the error happens in the except clause of your tr
On 02/12/2018 10:29, Dave Hill wrote:
> Having 'graduated' to Python 3.7, I thought I would explore
> Traceback (most recent call last):
>File "/home/pi/Code/TestVideo#4.py", line 31, in
> player.playVideo(FILE, 'HDMI')
>File "/home/pi/Code/VideoPlayer.py", line 51, in playVideo
>
I am a volunteer at a Heritage Railway in N.Wales and, amongst other
things, I provide electronics and software for various exhibits in the
museum. I use the Raspberry Pi to provide various video presentations,
employing the omxplayer.
I am in the process of updating an application known as th
On 31Mar2017 06:13, eryk sun wrote:
On Thu, Mar 30, 2017 at 10:51 PM, Cameron Simpson wrote:
This suggests that .communicate uses Threads to send and to gather data
independently, and that therefore the deadlock situation may not arise.
For Unix, communicate() uses select or poll. It uses th
Cameron!!!
You are 'da man!!
Read your exaplanation.. good stuff to recheck/test and investigate
over time
In the short term, I'll implement some tests!!
thanks!
On Thu, Mar 30, 2017 at 6:51 PM, Cameron Simpson wrote:
> I wrote a long description of how .communicate can deadlock.
>
> The
On Thu, Mar 30, 2017 at 10:51 PM, Cameron Simpson wrote:
> This suggests that .communicate uses Threads to send and to gather data
> independently, and that therefore the deadlock situation may not arise.
For Unix, communicate() uses select or poll. It uses threads on
Windows. Either way it avoid
I wrote a long description of how .communicate can deadlock.
Then I read the doco more carefully and saw this:
Warning: Use communicate() rather than .stdin.write, .stdout.read
or .stderr.read to avoid deadlocks due to any of the other OS
pipe buffers filling up and blocking the child process
On 30Mar2017 13:51, bruce wrote:
Trying to understand the "correct" way to run a sys command ("curl")
and to get the potential stderr. Checking Stackoverflow (SO), implies
that I should be able to use a raw/text cmd, with "shell=true".
I strongly recommend avoiding shell=True if you can. It ha
Trying to understand the "correct" way to run a sys command ("curl")
and to get the potential stderr. Checking Stackoverflow (SO), implies
that I should be able to use a raw/text cmd, with "shell=true".
If I leave the stderr out, and just use
s=proc.communicate()
the test works...
Any pointe
On Fri, May 1, 2015 at 8:03 AM, Albert-Jan Roskam wrote:
> I used a str for cmd because I found it more readable that way. I could do
> cmd.split().
Don't use cmd.split(). That just splits on whitespace without
respecting how the shell tokenizes the command. Use shlex.split(cmd)
instead.
> So o
On Thu, Apr 30, 2015 1:12 AM CEST eryksun wrote:
>On Wed, Apr 29, 2015 at 11:54 AM, Albert-Jan Roskam
> wrote:
>> Hmmm, that sounds pretty convincing indeed (makes it even stranger that CD
>> works the way it works).
>> I believe it threw a WindowsError, indicating t
On 30/04/15 01:48, eryksun wrote:
> Actually cmd.exe is fine with UNC paths.
cmd.exe cannot use a UNC path as the current directory.
Oops, my mistake. I got my POSIX and UNC mixed up.
I was thinking about forward slashes etc not network names.
Apologies for not reading the message properly.
--
On Wed, Apr 29, 2015 at 8:28 PM, eryksun wrote:
> After disabling the check, my previous example should work fine:
Except it doesn't accept paths relative to a UNC working directory:
(test) \\127.0.0.1\C$>cd Temp
The system cannot find the path specified.
And the cd command appears to i
On Wed, Apr 29, 2015 at 7:48 PM, eryksun wrote:
> cmd.exe was developed for OS/2 (1987) to replace COMMAND.COM (1981).
Actually, I stand corrected about the reason being cmd's 1980s
crustiness. Per [KB156276][1] this check was added to NT 4.0 (1996) to
address a vaguely described problem ("a UNC
On Wed, Apr 29, 2015 at 7:08 PM, Alan Gauld wrote:
> On 30/04/15 00:12, eryksun wrote:
>
>> the working directory, but the cmd.exe shell (being a crusty relic of
>> the 1980s) does not.
>
> Actually cmd.exe is fine with UNC paths. It's only when you
> combine them with Windows /option style that i
On 30/04/15 00:12, eryksun wrote:
the working directory, but the cmd.exe shell (being a crusty relic of
the 1980s) does not.
Actually cmd.exe is fine with UNC paths. It's only when you
combine them with Windows /option style that it has issues
but even then putting the path in quotes will usua
On Wed, Apr 29, 2015 at 11:54 AM, Albert-Jan Roskam
wrote:
> Hmmm, that sounds pretty convincing indeed (makes it even stranger that CD
> works the way it works).
> I believe it threw a WindowsError, indicating that the file(s) could not be
> found, because the dir was
> not changed. I actually
-
On Wed, Apr 29, 2015 4:11 PM CEST Peter Otten wrote:
>Albert-Jan Roskam wrote:
>
>> Hello,
>>
>> Windows has the 'feature' that the CD command does not work with UNC
>> paths. So in the code below, I cannot use the 'cwd' parameter of
>> subprocess.Popen. Therefore I
Albert-Jan Roskam wrote:
> Hello,
>
> Windows has the 'feature' that the CD command does not work with UNC
> paths. So in the code below, I cannot use the 'cwd' parameter of
> subprocess.Popen. Therefore I use pushd/popd to accomplish the same
> effect. Is there a better way to do this? (other th
On 04/29/2015 08:47 AM, Albert-Jan Roskam wrote:
Hello,
Windows has the 'feature' that the CD command does not work with UNC paths.
So in the code below, I cannot use the 'cwd' parameter of subprocess.Popen.
Therefore I use pushd/popd to accomplish the same effect. Is there a better way
to do t
Hello,
Windows has the 'feature' that the CD command does not work with UNC paths.
So in the code below, I cannot use the 'cwd' parameter of subprocess.Popen.
Therefore I use pushd/popd to accomplish the same effect. Is there a better way
to do this?
(other than using full path names everywhere,
On 10/28/2014 04:27 PM, Todd wrote:
> Centos has SELinux enabled by default. I dont know if SELinux is
> causing your problem, but it is always worth looking at.
>
> SELinux can keep a process from accessing files or executing another
> process.
>
> Try temporarily disabling SELinux by runnin
Centos has SELinux enabled by default. I dont know if SELinux is causing
your problem, but it is always worth looking at.
SELinux can keep a process from accessing files or executing another
process.
Try temporarily disabling SELinux by running setenforce=0 as root. Then
see if python does wha
On 28/10/14 19:23, Adam Jensen wrote:
platform. This is what I've discovered so far:
| | CentOS-6.5 | OpenBSD-5.5 | DragonFly-3.8.2 |
| bufsize | Python-3.4.1 | Python-3.3.2 | Python-3.3.3|
|-+--+--+-
On 10/28/2014 02:32 PM, Alan Gauld wrote:
> I tried -1 and 1 on my Lubuntu and it still works fine.
> Definitely weird, it begins to look like a CentOS build issue
> but what is CentOS doing different to Lubuntu/Suse/OpenBSD etc?
>
> From memory CentOS is basically a free version of Red Hat
> Ent
On 28/10/14 15:31, Adam Jensen wrote:
-
bufsize will be supplied as the corresponding argument to the open()
function when creating the stdin/stdout/stderr pipe file objects:
And I get these results (on CentOS-6.5-x86):
Update:
On 10/27/2014 09:50 PM, Adam Jensen wrote:
> What's weird is that I have two different python3.4 installations on
> this CentOS-6.5 machine and both have the same behavior (script hangs
> until Ctrl+C).
>
> I built this one (/opt/bin/python3.4) from source:
...
> But this one (~/anaconda3
On 10/27/2014 09:31 PM, Alan Gauld wrote:
> On 27/10/14 20:26, Adam Jensen wrote:
>
>> That's a bit bizarre. I too have the execution bit set for both the
>> python script and the shell script but the same (no joy) behavior occurs
>> on both:
>
>> $ ./subprocess_pipe.py
>
> Its a long shot but
On 27/10/14 20:26, Adam Jensen wrote:
That's a bit bizarre. I too have the execution bit set for both the
python script and the shell script but the same (no joy) behavior occurs
on both:
$ ./subprocess_pipe.py
Its a long shot but try explicitly invoking the interpreter:
$ python3 ./subpro
On 28/10/14 01:05, Adam Jensen wrote:
Thanks for giving it a try. The mailing list moderation delay is making
an interactive conversation a bit difficult.
Well, that much I can help with, you are now off moderation :-)
--
Alan G
Author of the Learn to Program web site
http://www.alan-g.me.uk/
On 10/27/2014 03:40 PM, David Abbott wrote:
>> It hangs at the print statement and, from the sound of the fans in the
>> computer, I suspect it spirals off into an infinite loop somewhere /
>> somehow. Does anyone have any ideas about what it is that I might be
>> misunderstanding?
>
> Works here.
On 10/27/2014 07:12 PM, Alan Gauld wrote:
> On 27/10/14 18:24, Adam Jensen wrote:
>> It hangs at the print statement and, from the sound of the fans in the
>> computer, I suspect it spirals off into an infinite loop somewhere
>
> It works fine on my Lubuntu 14 with Python3.4.
>
> How exactly are
On 10/27/2014 03:40 PM, David Abbott wrote:
>> It hangs at the print statement and, from the sound of the fans in the
>> computer, I suspect it spirals off into an infinite loop somewhere /
>> somehow. Does anyone have any ideas about what it is that I might be
>> misunderstanding?
>
> Works here
On 27/10/14 18:24, Adam Jensen wrote:
It hangs at the print statement and, from the sound of the fans in the
computer, I suspect it spirals off into an infinite loop somewhere
It works fine on my Lubuntu 14 with Python3.4.
How exactly are you running it? If I don't make parrot.sh executable
I
I did do this also;
david@heater ~/python_practice $ chmod a+x parrot.sh
david@heater ~/python_practice $ chmod a+x subprocess_pipe.py
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> It hangs at the print statement and, from the sound of the fans in the
> computer, I suspect it spirals off into an infinite loop somewhere /
> somehow. Does anyone have any ideas about what it is that I might be
> misunderstanding?
Works here.
david@heater ~/python_practice $ ./subprocess_pipe
Hi, I'm exploring Popen today and I seem to be having some trouble
deciphering the [documentation][1].
[1]: docs.python.org/3/library/subprocess.html#popen-constructor
In this example (below), I expect to start a shell script as a separate
process, send a line of text through a pipe (to the shell
On 28 January 2014 21:52, leam hall wrote:
> Python tutorial for 2.6 (using 2.4 -- don't ask), first code blurb under
> 17.1.1
>
>
> http://docs.python.org/2.6/library/subprocess.html?highlight=subprocess#subprocess.Popen
>
> How would you make an ssh to another box put data back in "p"? The
> go
On Tue, Jan 28, 2014 at 2:52 PM, leam hall wrote:
> Python tutorial for 2.6 (using 2.4 -- don't ask), first code blurb under
> 17.1.1
>
> http://docs.python.org/2.6/library/subprocess.html?highlight=subprocess#subprocess.Popen
>
> How would you make an ssh to another box put data back in "p"? The
On 28/01/14 19:52, leam hall wrote:
Python tutorial for 2.6 (using 2.4 -- don't ask), first code blurb under 17.1.1
http://docs.python.org/2.6/library/subprocess.html?highlight=subprocess#subprocess.Popen
How would you make an ssh to another box put data back in "p"? The
goal is to run a shell
Python tutorial for 2.6 (using 2.4 -- don't ask), first code blurb under 17.1.1
http://docs.python.org/2.6/library/subprocess.html?highlight=subprocess#subprocess.Popen
How would you make an ssh to another box put data back in "p"? The
goal is to run a shell command on a remote box and work with
Thanks to all who responded. I'm deeply into some of the links provided,
and my understanding has greatly increased.
Ray
On 08/22/2012 12:59 AM, Andreas Perstinger wrote:
> On 22.08.2012 03:39, Ray Jones wrote:
>> Does anyone know of a link to a really good tutorial that would help me
>> with s
On Tue, Aug 21, 2012 at 9:39 PM, Ray Jones wrote:
>
> Does anyone know of a link to a really good tutorial that would help me
> with subprocess.Popen? a tutorial that uses really small words and more
> examples than explanation? After 15 years of scripting, I'm ashamed to
> say that I'm still not
On 22.08.2012 03:39, Ray Jones wrote:
Does anyone know of a link to a really good tutorial that would help me
with subprocess.Popen? a tutorial that uses really small words and more
examples than explanation? After 15 years of scripting, I'm ashamed to
say that I'm still not all that familiar wit
Does anyone know of a link to a really good tutorial that would help me
with subprocess.Popen? a tutorial that uses really small words and more
examples than explanation? After 15 years of scripting, I'm ashamed to
say that I'm still not all that familiar with input, output, pipes, etc.
much beyon
This list is amazing, I scratch my head, think and think then finally
post a question, maybe its the act of spelling it out, ps ax showed 2
x 'tail' processes, I am guessing zombies of previous attempts, killed
them, all works AOK now
On 10 June 2012 10:06, dave selby wrote:
> I have a simple sc
I have a simple script to tail a log file for an error string, it
works AOK but there is an unexpected side effect, when I run it in a
shell.
if I
echo "ERROR TEST" >> LOG
in a separate shell, I get the following from the script
ERROR TEST
GOT YA :)
ERROR TEST
So it looks like I am getting std
"Neha P" wrote
I am newbie and want to know what is the difference
between subprocess.Popen() and subprocess.call() ?
Simply speaking, call() is a way to make subprocess
easier to use. Popen gives you much more powerful
options but that flexibility means it's harder to use.
when is it b
Hi all,
I am newbie and want to know what is the difference between subprocess.Popen()
and subprocess.call() ?
when is it best to use each one?
Any help appreciated!!
Regards,
Neha___
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