env bug ?

[Henry Spencer]

On Mon, 7 Mar 2005, John Sellens wrote:
> |     #!/usr/bin/env echo foo
> |     /usr/bin/env: echo foo: No such file or directory
> 
> Hmmm - there seems to be something different in the way Linux does #!
> lines than one might expect...

A very careful reading of the execve(2) manpage (on a somewhat old Red
Hat) indicates that the contents of the #! line are #!, the full pathname
of an interpreter, and optionally an argument.  Note, "argument", singular
not plural.  So all the remaining text on the line is being taken as *one*
argument.

This is actually quite a common restriction; supplying more than one
argument on the #! line has never been very portable. 

> env is behaving correctly, based on the arguments it is given.

I concur.

> Some (including me) might claim that the kernel is invoking env
> incorrectly.

I wouldn't go that far... quite.  I would say that the kernel is handling
an out-of-spec situation rather ungracefully.  It isn't actually wrong but
really ought to do better.

                                                          Henry Spencer
                                                       henry-lqW1N6Cllo0sV2N9l4h3zg at public.gmane.org

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