[Wolves] Another python question, running commands with variables as arguments.

[Simon Burke]

On Wed, Aug 17, 2011 at 8:12 PM, Alex Willmer <alex at moreati.org.uk> wrote:
> On 17 August 2011 12:56, Simon Burke <simonb at fatsportsman.eu> wrote:
>> All I want to do is run a command, but arguments are stored in variables.
>>
>> This is where Im struggling.
>>
>> I have been using subprocess.Popen to run commands with little
>> problem, but as soon as I want to get variables involved it all falls
>> to pieces.
>> My understanding is that I need to possibly use
>> subprocess.Popen,communicate but I cant find a clear example or doc to
>> detail how I am supposed to do this.
>>
>> Can someone help or point me in the right direction?
>
> Simon,
> It depends what you mean by variables and what you want to achieve.
> Are you talking about Python variables (e.g. sys.argv), or environment
> variables (i.e. $PWD, $HOME etc)?
>
> You could use a variable as one of the arguments doing something like
> the following:
> Python 2.6.5 (r265:79063, Apr 16 2010, 13:09:56)
> [GCC 4.4.3] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>>>> import subprocess
>>>> path = '/'
>>>> pipe = subprocess.Popen(['/bin/ls', path], stdout=subprocess.PIPE)
>>>> pipe.communicate()
> ('bin\nboot\ncdrom\ndev\netc\nhome\ninitrd.img\nlib\nlost+found\nmedia\nmnt\nopt\nproc\nroot\nsbin\nselinux\nsrv\nsys\ntmp\nusr\nvar\nvmlinuz\n',
> None)
>
> If you paste the code you have, and ask more specific question(s) we
> should be able to help you much better. In general, vague questions
> don't help us or you.
>
> Regards, Alex

An example of the code I'm trying to use is: (the code currently just
prints out the command).

                        for filesys in bp1_fs:
                                print "mount %s:/vol/%s  -t nfs -o %s"
% (nas1, filesys, moptions)
                        for ipaddr in bp1_ip:
                                print "ip addr add %s dev %s" % (ipaddr, int)
                        print "su - %s -c startdb" % (bp1_usr)
                        for inst in bp1_inst:
                                print "su - %s -c startsap %s" % (bp1_usr, inst)


So far I have been pointed into putting the commands into an array and
run through it with Popen.communicate, but its the how I'm struggling
with.

Thanks,
Simon.