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Re: Quotation Ugliness

References <grifkb-kpo1.ln1@ozzie.tundraware.com> <mailman.16304.1416966896.18130.python-list@python.org> <54756D5F.4040806@tundraware.com> <mailman.16320.1417007333.18130.python-list@python.org> <5475EAB3.7060503@tundraware.com>
Date 2014-11-27 02:06 +1100
Subject Re: Quotation Ugliness
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.16329.1417014387.18130.python-list@python.org> (permalink)

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On Thu, Nov 27, 2014 at 1:58 AM, Tim Daneliuk <tundra@tundraware.com> wrote:
> The specific program in question I am modifying is
> one that takes a shell command and executes it remotely on many machines.
> The problem I am trying to solve is to determine whether the user needs to
> provide a sudo password or not.  Right now, the program just naively checks
> the arguments to see if .startswith("sudo').  As the example given
> illustrates,
> that clearly fails if the sudo is given later in a longer pipeline.
>
> Scanning the whole argument string for 'sudo' is better but will yield
> false positives if the string is inside a quote of some sort.  Since I have
> to solve the problem for ' and " delimiters, I thought I'd generalize the
> solution
> for other strings possibly being quoted by other delimiters.

Tell whoever asked you to do this that it's a fundamentally impossible
task. Quotes have nothing to do with whether or not "sudo" is what
will be executed. Your only solutions will involve either parsing the
entire command line, exactly the way the shell does (including knowing
everything the shell knows at the far end, like command aliases), or
letting the shell do the parsing and then tinkering with what the
"sudo" command does. You can't easily and safely predict it based on
simple string processing.

ChrisA

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Thread

Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-25 18:18 -0600
  Re: Quotation Ugliness Tim Chase <python.list@tim.thechases.com> - 2014-11-25 18:40 -0600
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-25 19:18 -0600
      Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-26 12:32 +1100
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:00 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:00 -0600
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-25 19:18 -0600
  Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-26 11:44 +1100
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-25 19:20 -0600
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-25 19:20 -0600
      Re: Quotation Ugliness Tim Chase <python.list@tim.thechases.com> - 2014-11-25 19:44 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:01 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:01 -0600
  Re: Quotation Ugliness Ben Finney <ben+python@benfinney.id.au> - 2014-11-26 12:54 +1100
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:04 -0600
    Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 00:04 -0600
      Using a password with ‘sudo’ (was: Quotation Ugliness) Ben Finney <ben+python@benfinney.id.au> - 2014-11-26 18:02 +1100
      Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-26 18:10 +1100
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 08:59 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 08:59 -0600
      Re: Quotation Ugliness Tim Chase <python.list@tim.thechases.com> - 2014-11-26 06:56 -0600
        Re: Quotation Ugliness Jussi Piitulainen <jpiitula@ling.helsinki.fi> - 2014-11-26 15:45 +0200
          Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 01:37 +1100
          Re: Quotation Ugliness Tim Chase <python.list@tim.thechases.com> - 2014-11-26 08:26 -0600
          Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 02:07 +1100
          Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 02:09 +1100
            Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:36 -0600
            Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:36 -0600
              Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 02:48 +1100
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:55 -0600
                Re: Quotation Ugliness random832@fastmail.us - 2014-11-26 11:00 -0500
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 10:02 -0600
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 10:02 -0600
                Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 03:13 +1100
                Re: Quotation Ugliness random832@fastmail.us - 2014-11-26 11:16 -0500
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 10:54 -0600
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 10:54 -0600
                Re: Quotation Ugliness alister <alister.nospam.ware@ntlworld.com> - 2014-11-26 16:45 +0000
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 10:54 -0600
                Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:55 -0600
              Re: Quotation Ugliness random832@fastmail.us - 2014-11-26 10:53 -0500
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 08:58 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 08:58 -0600
          Re: Quotation Ugliness Chris Angelico <rosuav@gmail.com> - 2014-11-27 02:06 +1100
          Re: Quotation Ugliness Tim Chase <python.list@tim.thechases.com> - 2014-11-26 09:23 -0600
          Re: Quotation Ugliness Ben Finney <ben+python@benfinney.id.au> - 2014-11-27 07:24 +1100
      Re: Quotation Ugliness random832@fastmail.us - 2014-11-26 09:12 -0500
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:02 -0600
        Re: Quotation Ugliness Tim Daneliuk <tundra@tundraware.com> - 2014-11-26 09:02 -0600
          Re: Quotation Ugliness random832@fastmail.us - 2014-11-26 10:16 -0500

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