Hi Thibault,

Thanks for clarifying.

I think at this point we need to basically decide between:

1) Modifying rosrun to have the separate command-line syntax (meant
for scripts, not users).
2) Create a new ros/bin/ros-shebang (name TBD) to support this script
use case instead.

Given that this relates to a major command-line tool like rosrun, I'd
rather not decide by fiat -- any opinions out there as to which is
preferred? (+1/-1 votes welcome)

 - Ken



On Fri, Aug 12, 2011 at 2:17 PM, Thibault Kruse <kruset@in.tum.de> wrote:
>
>> Why is the "rosrun ABSOLUTE_FILENAME [ARGS]" necessary for some
>> scripts?
>
> Because if I put
> #! /usr/bin/env rosrun
>
> in a script file named foobar.xyz, make foobar.xyz executable, and call
>
> $ ./foobar.xyz arg1 arg2 arg3
>
> then bash will effectively call
>
> rosrun ./foobar.xyz arg1 arg2 arg3
>
> (So actually the syntax is just rosrun FILENAME [ARGS], not necessarily
> the absolute path )
>
> So the syntax is merely for shebang, NOT for anyone ever putting
> rosrun /path/to/filename
> into any script or the command line.
>
>>     From the perspective of command-line usage, it doesn't add
>> much value as it is equivalent to the user typing:
>>
>> ./ABSOLUTE_FILENAME [ARGS]
> Absolutely, yes. That's my working assumption, the reason why I think
> rosrun could be used instead of rosbang. That's what rosbang would also
> do. So a rosbang command would be totally useless for command line usage.
>
> The syntax of rosbang would equally be
> rosbang FILENAME [ARGS]
> and its effect would be the same as
> ./FILENAME [ARGS]
> There is no reason why any user would ever type rosbang into the command
> line. It would exclusively be used in
> #! /usr/bin/env rosbang
>
>> If there is a special need for a script, I would suggest a special
>> option, e.g. '-f', to flag the different usage and make it
>> unambiguous.
> No, not only is that not necessary, but it would make it impossible to
> use rosrun that way, as
> #! /usr/bin/env rosrun -f
> is not possible.
>
> I was not aware of the rosexec thread. Went through it now. Introducing
> rosexec PACKAGE/KEY as syntax would overlap with rosexec
> directory/filename syntax, as far as i can see those could never be
> merged into one command without the possibility of surprising the user
> with unexpected actions in rare cases. So if that is still a
> perspective, a separate command like rosbang might be wiser.
>
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