Passing all extra commandline arguments to python program, Optparse raises exception

[Rhodri James]

On Sun, 19 Apr 2009 14:45:45 +0100, David Stanek <dstanek at dstanek.com>  
wrote:

> On Thu, Apr 16, 2009 at 10:05 AM, sapsi <saptarshi.guha at gmail.com> wrote:
>> Hello,
>> Im using optparse and python 2.6 to parse some options, my commandline
>> looks like
>>
>> prog [options] start|stop extra-args-i-will-pas-on
>>
>> The options are --b --c --d
>>
>> The extra options are varied are are passed onto another program e.g --
>> quiet --no-command , my program doesnt care what these are but instead
>> passes them onto another program.
>>
>> I know these will always follow start|stop.
>>
>> However optparse tries to process them and throws an exception - how
>> can i prevent this without placing all the extra-args in quotes.
>>
>
>
> In Linux (maybe in Windows) you can tell an application to stop
> processing args by using '--'. Given this code:
>     import sys
>     from optparse import OptionParser
>     op = OptionParser()
>     op.add_option('--a', dest='a', action='store_true', default=False)
>     op.add_option('--b', dest='b', action='store_true', default=False)
>     opts, args = op.parse_args(sys.argv)
>     print 'opts:', opts
>     print 'args:', args
>
> Here is an example use:
>     eee0:~% python junk.py --a -- --c
>     {'a': True, 'b': False}
>     ['junk.py', '--c']
>
>

It's only a convention, but it is one that optparse follows, so it'll
work quite happily on any platform.  The info on it is buried in the
documentation, in an example of options with a variable number of
arguments:

"""
And you have to deal with certain intricacies of conventional Unix
command-line parsing that optparse normally handles for you. In
particular, callbacks should implement the conventional rules for
bare "--" and "-" arguments:

* either "--" or "-" can be option arguments
* bare "--" (if not the argument to some option): halt command-line
      processing and discard the "--"
* bare "-" (if not the argument to some option): halt command-line
      processing but keep the "-" (append it to parser.largs)
"""

-- 
Rhodri James *-* Wildebeeste Herder to the Masses