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From: Ian Kelly <ian.g.kelly@gmail.com>
Date: Thu, 1 Oct 2015 16:58:02 -0600
Subject: Re: Only getting the first 6 lines
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On Thu, Oct 1, 2015 at 3:58 PM, Cecil Westerhof <Cecil@decebal.nl> wrote:
> I want to get the first 6 lines of ps output. For this I use:
> ========================================================================
> from subprocess import check_output
>
> ps_command = ('ps', '-eo', 'user,pid,pcpu,pmem,stat,start,time,cmd', '--sort')
> message = '\n'.join(check_output(ps_command + ('-%cpu',)).decode("utf-8").splitlines()[0:6])
> ========================================================================
>
> It works, but does not look very efficient. Is there a better way to
> do this?

Instead of using check_output which reads the entire output, you could
create a Popen with stdin=None, stdout=PIPE, stderr=None, and then
read just the first six lines. Don't forget to clean up the subprocess
afterward.