Output from the shell:
[cpn@s0 teste]$ set | grep IFS
IFS=$' \t\n'
Output from subprocess.Pope n():
>>import subprocess as sub
p = sub.Popen('set | grep IFS', shell=True, stdout=sub.PIPE )
p.stdout.read lines()[1]
"IFS=' \t\n"
Both outputs for comparison:
IFS=$' \t\n'
"IFS=' \t\n"
The subprocess.Pope n() output is missing the $ and the last '
How to get the raw shell output from subprocess.Pope n()?
Regards, Clodoaldo Pinto Neto 9  9378 
Clodoaldo Pinto Neto wrote:
Output from the shell:
[cpn@s0 teste]$ set | grep IFS
IFS=$' \t\n'
Output from subprocess.Pope n():
>>>import subprocess as sub
p = sub.Popen('set | grep IFS', shell=True, stdout=sub.PIPE )
p.stdout.rea dlines()[1]
"IFS=' \t\n"
Both outputs for comparison:stdo ut=subprocess.P IPE)
IFS=$' \t\n'
"IFS=' \t\n"
The subprocess.Pope n() output is missing the $ and the last '
if you expect one line of output, why are you doing readlines()[1] ?
>>f = subprocess.Pope n("set | grep IFS", shell=True,
f.stdout.read lines()[1]
Traceback (most recent call last):
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
IndexError: list index out of range
this works for me:
>>f = subprocess.Pope n("set | grep IFS", shell=True,
stdout=subproce ss.PIPE)
>>f.stdout.read lines()
["IFS=$' \\t\\n'\n"]
what does the above return on your machine?
</F>
Fredrik Lundh wrote:
this works for me:
>>f = subprocess.Pope n("set | grep IFS", shell=True,
stdout=subproce ss.PIPE)
>>f.stdout.read lines()
["IFS=$' \\t\\n'\n"]
what does the above return on your machine?
>>f = subprocess.Pope n("set | grep IFS", shell=True, stdout=subproce ss.PIPE)
f.stdout.read lines()
["BASH_EXECUTION _STRING='set | grep IFS'\n", "IFS=' \t\n"]
I'm on FC5
Clodoaldo Pinto Neto <cl************ *@gmail.comwrot e:
>Fredrik Lundh wrote:
>this works for me:
> >>f = subprocess.Pope n("set | grep IFS", shell=True,
stdout=subproc ess.PIPE)
> >>f.stdout.read lines()
["IFS=$' \\t\\n'\n"]
what does the above return on your machine?
>>>f = subprocess.Pope n("set | grep IFS", shell=True, stdout=subproce ss.PIPE)
f.stdout.rea dlines()
["BASH_EXECUTION _STRING='set | grep IFS'\n", "IFS=' \t\n"]
I'm on FC5
OK, there's something going on here:
$ set | grep IFS
IFS=$' \t\n'
$ python
Python 2.4.1 (#2, May 5 2005, 11:32:06)
[GCC 3.3.5 (Debian 1:3.3.5-12)] on linux2
Type "help", "copyright" , "credits" or "license" for more information.
>>import subprocess
f = subprocess.Pope n("set | grep IFS", shell=True, stdout=subproce ss.PIPE)
f.stdout.read lines()
["IFS=' \t\n"]
>>>
(Hmph, I don't have any other non-Windows boxes with >=2.4 to hand.)
--
\S -- si***@chiark.gr eenend.org.uk -- http://www.chaos.org.uk/~sion/
___ | "Frankly I have no feelings towards penguins one way or the other"
\X/ | -- Arthur C. Clarke
her nu becomeþ se bera eadward ofdun hlæddre heafdes bæce bump bump bump
Now we have 3 different outputs from 3 people to the command:
>>f = subprocess.Pope n("set | grep IFS", shell=True,
stdout=subproce ss.PIPE)
>>f.stdout.read lines()
>From me on FC5:
["BASH_EXECUTION _STRING='set | grep IFS'\n", "IFS=' \t\n"]
>From Fredrik Lundh on unknown OS:
["IFS=$' \\t\\n'\n"]
>From Sion Arrowsmith on Debian 1:3.3.5-12:
["IFS=' \t\n"]
I found this problem while developing a CGI shell: http://code.google.com/p/cgpy-shell/
Although the cgi-shell is working quite well, this issue is a show
stopper for that project. I need a stable/reliable output from Popen().
It looks like each bash or sh version outputs things differently, with
different escaping.
It is not a problem if there is only one or more than one line in the
returned list as i will always get the last one. The problem is the
escaping.
Clodoaldo Pinto Neto wrote:
Output from the shell:
[cpn@s0 teste]$ set | grep IFS
IFS=$' \t\n'
Output from subprocess.Pope n():
>import subprocess as sub
p = sub.Popen('set | grep IFS', shell=True, stdout=sub.PIPE )
p.stdout.readl ines()[1]
"IFS=' \t\n"
Both outputs for comparison:
IFS=$' \t\n'
"IFS=' \t\n"
The subprocess.Pope n() output is missing the $ and the last '
How to get the raw shell output from subprocess.Pope n()?
You are getting the raw shell output, it's just that subprocess uses
the default shell (/bin/sh) and not your personal shell. Try running
/bin/sh and run the set|grep command.
I can't see any obvious way to ask subprocess to use a shell other than
the default.
If you need a particular shell, you could use a shell script, e.g.
myscript.sh:
#!/bin/bash
set|grep IFS
and call that with shell=False
p = sub.Popen('/path/to/myscript.sh', stdout=sub.PIPE ) sj*******@yahoo .com wrote:
I can't see any obvious way to ask subprocess to use a shell other than
the default.
-c ?
>>f = Popen(["/bin/bash", "-c", "set|grep IFS"], stdout=PIPE)
f.stdout.read ()
"IFS=$' \\t\\n'\n"
>>f = Popen(["/bin/sh", "-c", "set|grep IFS"], stdout=PIPE)
f.stdout.read ()
"IFS=' \t\n"
</F>
Fredrik Lundh wrote:
sj*******@yahoo .com wrote:
I can't see any obvious way to ask subprocess to use a shell other than
the default.
-c ?
>>f = Popen(["/bin/bash", "-c", "set|grep IFS"], stdout=PIPE)
>>f.stdout.read ()
"IFS=$' \\t\\n'\n"
>>f = Popen(["/bin/sh", "-c", "set|grep IFS"], stdout=PIPE)
>>f.stdout.read ()
"IFS=' \t\n"
It solves my problem:
>>f = sub.Popen(['/bin/sh', '-c', 'set|grep IFS'], stdout=sub.PIPE )
f.stdout.read ()
"BASH_EXECUTION _STRING='set|gr ep IFS'\nIFS=' \t\n"
>>f = sub.Popen(['/bin/bash', '-c', 'set|grep IFS'], stdout=sub.PIPE )
f.stdout.read ()
"BASH_EXECUTION _STRING='set|gr ep IFS'\nIFS=$' \\t\\n'\n"
But I still don't understand what is happening. The manual says that
when shell=True the executable argument specifies which shell to use:
>>f = sub.Popen('set| grep IFS', shell=True, executable='/bin/sh', stdout=sub.PIPE )
f.stdout.read ()
"BASH_EXECUTION _STRING='set|gr ep IFS'\nIFS=' \t\n"
>>f = sub.Popen('set| grep IFS', shell=True, executable='/bin/bash', stdout=sub.PIPE )
f.stdout.read ()
"BASH_EXECUTION _STRING='set|gr ep IFS'\nIFS=' \t\n"
To make my confusion bigger, in Fedora sh is just a link to bash:
$ ll /bin/*sh
-rwxr-xr-x 1 root root 720888 Feb 11 2006 /bin/bash
lrwxrwxrwx 1 root root 4 Aug 28 22:53 /bin/csh -tcsh
-rwxr-xr-x 1 root root 1175496 Aug 17 13:19 /bin/ksh
lrwxrwxrwx 1 root root 4 Feb 24 2006 /bin/sh -bash
-rwxr-xr-x 1 root root 349312 Aug 17 15:20 /bin/tcsh
-rwxr-xr-x 1 root root 514668 Feb 12 2006 /bin/zsh
Clodoaldo Pinto Neto wrote:
But I still don't understand what is happening. The manual says that
when shell=True the executable argument specifies which shell to use:
no, it says that when shell=True, it runs the command "through" the
default shell. that is, it hands it over to the shell for execution,
pretty much as if you'd typed it in yourself.
To make my confusion bigger, in Fedora sh is just a link to bash:
that only means that the programs share the same binary, not that they
necessarily have exactly the same behaviour:
$ man bash
...
INVOCATION
...
If bash is invoked with the name sh, it tries to mimic the
startup behavior of historical versions of sh as closely as
possible, while conforming to the POSIX standard as well.
...
</F>
Fredrik Lundh wrote:
Clodoaldo Pinto Neto wrote:
But I still don't understand what is happening. The manual says that
when shell=True the executable argument specifies which shell to use:
no, it says that when shell=True, it runs the command "through" the
default shell. that is, it hands it over to the shell for execution,
pretty much as if you'd typed it in yourself.
"If shell=True, the executable argument specifies which shell to use."
Taken from 6.8.1 v2.4:
"The executable argument specifies the program to execute. It is very
seldom needed: Usually, the program to execute is defined by the args
argument. If shell=True, the executable argument specifies which shell
to use. On Unix, the default shell is /bin/sh. On Windows, the default
shell is specified by the COMSPEC environment variable." This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics | |
by: jas |
last post by:
I would like to redirect the output from os.system to a variable, but
am having trouble. I tried using os.popen(..).read() ...but that
doesn't give me exactly what i want.
...this is windows by the way.
For example:
tmp = os.popen("hostname").read()
....works as expected.
|
by: Darren Dale |
last post by:
I'm a developer on the matplotlib project, and I am having trouble with the
subprocess module on windows (Python 2.4.2 on winXP). No trouble to report
with linux. I need to use _subprocess instead of pywin32, but my trouble
exists with either option:
import subprocess
process = subprocess.Popen(, stderr=subprocess.STDOUT,
stdout=subprocess.PIPE)
stat = process.wait()
print process.stdout.read()
|
by: Kkaa |
last post by:
I'm using the os.system command in a python script on Windows to run a
batch file like this:
os.system('x.exe')
The third-party program x.exe outputs some text to the console that I
want to prevent from being displayed. Is there a way to prevent the
output of x.exe from python?
|
by: johnny |
last post by:
How do I pipe the output, generated from os.system(some_command), to
the logging file?
|
by: nathan.shair |
last post by:
Hello,
I searched on Google and in this Google Group, but did not find any
solution to my problem.
I'm looking for a way to output stdout/stderr (from a subprocess or
spawn) to screen and to at least two different files.
eg.
stdout/stderr -screen
| | |
by: Tobiah |
last post by:
I am not sure how to capture the output of a command
using subprocess without creating a temp file. I was
trying this:
import StringIO
import subprocess
file = StringIO.StringIO()
subprocess.call("ls", stdout = file)
|
by: rparimi |
last post by:
I am trying to redirect stderr of a process to a temporary file and
then read back the contents of the file, all in the same python
script. As a simple exercise, I launched /bin/ls but this doesn't
work:
#!/usr/bin/python
import subprocess as proc
import tempfile
name = tempfile.NamedTemporaryFile(mode='w+b')
print 'name is '+ name.name
|
by: Jeremy Banks |
last post by:
Hi. I wondered if anyone knew the rationale behind the naming of the
Popen class in the subprocess module. Popen sounds like the a suitable
name for a function that created a subprocess, but the object itself is
a subprocess, not a "popen". It seems that it would be more accurate to
just name the class Subprocess, can anyone explain why this is not the
case?
Thank you.
|
by: thedsadude |
last post by:
Hello,
I'm launching a script as follows:
<code>
p = subprocess.Popen()
p.wait()
</code>
If p.py writes to sys.stdout, then it is shown on the console.
|
by: marktang |
last post by:
ONU (Optical Network Unit) is one of the key components for providing high-speed Internet services. Its primary function is to act as an endpoint device located at the user's premises. However, people are often confused as to whether an ONU can Work As a Router. In this blog post, we’ll explore What is ONU, What Is Router, ONU & Router’s main usage, and What is the difference between ONU and Router. Let’s take a closer look !
Part I. Meaning of...
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language synchronization. With a Microsoft account, language settings sync across devices. To prevent any complications,...
| | |
by: Oralloy |
last post by:
Hello folks,
I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>".
The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed.
This is as boiled down as I can make it.
Here is my compilation command:
g++-12 -std=c++20 -Wnarrowing bit_field.cpp
Here is the code in...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that captivates audiences and drives business growth.
The Art of Business Website Design
Your website is...
|
by: isladogs |
last post by:
The next Access Europe User Group meeting will be on Wednesday 1 May 2024 starting at 18:00 UK time (6PM UTC+1) and finishing by 19:30 (7.30PM).
In this session, we are pleased to welcome a new presenter, Adolph Dupré who will be discussing some powerful techniques for using class modules.
He will explain when you may want to use classes instead of User Defined Types (UDT). For example, to manage the data in unbound forms.
Adolph will...
|
by: conductexam |
last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one.
At the time of converting from word file to html my equations which are in the word document file was convert into image.
Globals.ThisAddIn.Application.ActiveDocument.Select();...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in the same network. But I'm wondering if it's possible to do the same thing, with 2 Pfsense firewalls...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
| | |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating effective websites that not only look great but also perform exceptionally well. In this comprehensive...
| |
