execute commands and return output

[billiejoex]

Hi all. I'm searching for a portable (working on *nix and win32) function
that executes a system command and encapsulate its output into a string.
Searching for the web I found this:

os.popen('command').read()

It is perfect but when che command return an error the funciotn returns an
empy string.
Does it is possible to return stdout and stderr too?

Best regards

[Leif K-Brooks]

billiejoex wrote:

Hi all. I'm searching for a portable (working on *nix and win32) function
that executes a system command and encapsulate its output into a string.
Searching for the web I found this:

os.popen('command').read()

It is perfect but when che command return an error the funciotn returns an
empy string.
Does it is possible to return stdout and stderr too?

Use subprocess:

from subprocess import Popen, PIPE
proc = Popen(['command', 'arg', 'arg'], stdout=PIPE, stderr=PIPE)
return_code = proc.wait()
if return_code == 0:
print "Success:\n%s" % proc.stdout.read()
else:
print "Failure %s:\n%s" % (return_code, proc.stderr.read())

[Fredrik Lundh]

"billiejoex" wrote:

Hi all. I'm searching for a portable (working on *nix and win32) function that executes a system command and encapsulate its
output into a string.
Searching for the web I found this:

os.popen('command').read()

It is perfect but when che command return an error the funciotn returns an empy string.
Does it is possible to return stdout and stderr too?

see the variations popen2, popen3 and popen4:

http://docs.python.org/lib/os-newstreams.html

or use the subprocess module:

http://docs.python.org/lib/module-subprocess.html

</F>

[billiejoex]

Thank you for your help but I'm searching a different way.
Moreover it doesn't work always (for exaple: try a 'dir' command).
Because of I'm implementing a remote shell the
[[os.popen('command').read()]] rapresents the best for me because it can
also accepts arguments direclty (for example:
os.popen('netstat -a -n -o').read() and this is a great advantage.
I was looking at sys.stdout and sys.stderr. Can they be helpful?

Cheers

Use subprocess:

from subprocess import Popen, PIPE
proc = Popen(['command', 'arg', 'arg'], stdout=PIPE, stderr=PIPE)
return_code = proc.wait()
if return_code == 0:
print "Success:\n%s" % proc.stdout.read()
else:
print "Failure %s:\n%s" % (return_code, proc.stderr.read())

[Do Re Mi chel La Si Do]

Hi !

Look (the doc for) Popen2, Popen3, Popen4 & Subprocess

@-salutations

Michel Claveau

[Fredrik Lundh]

"billiejoex" wrote:

Moreover it doesn't work always (for exaple: try a 'dir' command).

why use os.system("dir") when Python already offers things
like os.listdir, os.walk, and glob.glob ?

</F>

[Leif K-Brooks]

billiejoex wrote:

Thank you for your help but I'm searching a different way.
Moreover it doesn't work always (for exaple: try a 'dir' command).
Because of I'm implementing a remote shell the
[[os.popen('command').read()]] rapresents the best for me because it can
also accepts arguments direclty (for example:
os.popen('netstat -a -n -o').read() and this is a great advantage.

If you really need shell evaluation, try subprocess.Popen('foo',
shell=True) instead.

[tiissa]

billiejoex wrote:

Hi all. I'm searching for a portable (working on *nix and win32) function
that executes a system command and encapsulate its output into a string.
Searching for the web I found this:

os.popen('command').read()

It is perfect but when che command return an error the funciotn returns an
empy string.
Does it is possible to return stdout and stderr too?

You may want to look at the subprocess [1] module and its Popen class [2].

[1] http://python.org/doc/2.4.1/lib/module-subprocess.html
[2] http://python.org/doc/2.4.1/lib/node234.html

[billiejoex]

Thanks for suggestions.
I'll try one of these solutions soon.