Re: empty stdout (subprocess.run)

2022-01-20 Thread James Smith 
On Wednesday, January 19, 2022 at 11:14:28 PM UTC-5, cameron...@gmail.com wrote:

> But I recommend you use shell=False and make: 
> 
> cmd = ["/usr/bin/transmission-remote", "--torrent", str(torrentno), "--info"] 

I like that. :-)
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Re: empty stdout (subprocess.run)

2022-01-20 Thread James Smith 
On Wednesday, January 19, 2022 at 11:08:58 PM UTC-5, Dennis Lee Bieber wrote:

> Don't you need to provide for that %s? Perhaps 
> 
> cmd="/usr/bin/transmission-remote --torrent %s --info" % torrentno 

That works, thanks.
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Re: empty stdout (subprocess.run)

2022-01-19 Thread Cameron Simpson 
On 19Jan2022 19:16, James Smith  wrote:
>I'm trying to run a shell command but the stdout is empty:
>
>import subprocess
>
>torrentno=8
>cmd="/usr/bin/transmission-remote --torrent %s --info", str(torrentno)
>res=subprocess.run(cmd, shell=True, check=True, universal_newlines=True, 
>capture_output=True)
>print(res)
>
>CompletedProcess(args=('/usr/bin/transmission-remote --torrent %s --info', 
>'1'), returncode=0, stdout='', stderr='')

If you're using shell=True (please don't) you want cmd to be a string.  
You have defined it as a 2-tuple. You can even see that in the 
CompletedProcess object you printed.

I think you want to % substitue torrentno into the format string.

But I recommend you use shell=False and make:

cmd = ["/usr/bin/transmission-remote", "--torrent", str(torrentno), 
"--info"]

because assembling commands with % formatting is a recipe for injection 
attacks. Look up "Little Bobby Tables", which is an SQL example of what 
you're doing with the shell.

Cheers,
Cameron Simpson 
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Re: empty stdout (subprocess.run)

2022-01-19 Thread Dennis Lee Bieber 
On Wed, 19 Jan 2022 19:16:19 -0800 (PST), James Smith
 declaimed the following:

>I'm trying to run a shell command but the stdout is empty:
>
>import subprocess
>
>torrentno=8
>cmd="/usr/bin/transmission-remote --torrent %s --info", str(torrentno)

Don't you need to provide for that %s? Perhaps

cmd="/usr/bin/transmission-remote --torrent %s --info" % torrentno

As coded, you are passing a TUPLE of two strings as cmd (fyi: the %s will
take the string representation of whatever is the matching argument on the
right, so str() isn't needed -- and if you need a number for both --torrent
and --info you'll need another %s, and (torrentno, torrentno) on the right)

>res=subprocess.run(cmd, shell=True, check=True, universal_newlines=True, 
>capture_output=True)
>print(res)
>
>CompletedProcess(args=('/usr/bin/transmission-remote --torrent %s --info', 
>'1'), returncode=0, stdout='', stderr='')


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empty stdout (subprocess.run)

2022-01-19 Thread James Smith 
I'm trying to run a shell command but the stdout is empty:

import subprocess

torrentno=8
cmd="/usr/bin/transmission-remote --torrent %s --info", str(torrentno)
res=subprocess.run(cmd, shell=True, check=True, universal_newlines=True, 
capture_output=True)
print(res)

CompletedProcess(args=('/usr/bin/transmission-remote --torrent %s --info', 
'1'), returncode=0, stdout='', stderr='')
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