[ros-users] [Ros-developers] suggest new ros shebang command

Ken Conley kwc at willowgarage.com
Sun Aug 21 17:50:40 UTC 2011

Hi Thibault,

I just saw this recipe on ActiveState [1] which may get around the
previous csh vs. sh issues.  Works in roslaunch/rosh.  Is this
sufficient for your roslisp loading needs?


LOADER=''''; exec rosrun rosh rosh "$0" "$@" #'''

print packages

[1]: http://code.activestate.com/recipes/577851-teach-the-hashbang-header-new-tricks-using-a-dual-/

On Mon, Aug 15, 2011 at 9:58 AM, Ken Conley <kwc at willowgarage.com> wrote:
> 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 at 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:
>> 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
>> 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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