Re: Unix invocation (was Re: Inferring the location of a Lua script)

[KHMan <keinhong@...>]

James Graves wrote:
> On Fri, Apr 30, 2010 at 09:58:56AM +0200, steve donovan wrote:
> > On Fri, Apr 30, 2010 at 8:09 AM, Stuart P. Bentley wrote:
> > > If your script is run in the same place as the application, I've heard
> > > Windows replaces ! or !! with the path up to the running executable.
> > On Unix, typically you write your Lua script like so and make it executable:
> >
> > -- ltest
> > #!/usr/local/bin/lua
> > print('I am '..arg[0])
> >
> > And you get exactly what you need from arg[0]
> >
> > ~$ ltest
> > I am /home/sdonovan/bin/ltest
>
> I promote the use of this for Unix shell script invocation:
>
>     #!/usr/bin/env lua
>     print('I am '..arg[0])
>
> This way, it will find whichever lua is first in your execution path,
> and run that.  Other people running your script, which may have their
> own version of Lua, will be using theirs instead.  And people who
> don't have their own copy of Lua will use the system one at
> /usr/bin/lua .

Another 1cent. Lorenzo might be considering the building of 
self-contained scripted applications, in which case the use of 
shell scripts might or might not be so appropriate.

In any case arg[0] may not work as we want when fiddling with 
symbolically-linked executables in the style of busybox, I think 
arg[0] gives the symlink name. So we'd need to make a call to get 
the path linked to the symlink or check with /proc/self, which is 
not portable.

--
Cheers,
Kein-Hong Man (esq.)
Kuala Lumpur, Malaysia