From: Jeremie Courreges-Anglas <jca@wxcvbn.org>
Subject: Re: Support for /usr/bin/env -S (kind of)
To: Manuel Giraud <manuel@ledu-giraud.fr>
Cc: Theo de Raadt <deraadt@openbsd.org>, tech@openbsd.org
Date: Fri, 18 Jul 2025 18:55:18 +0200

On Fri, Jul 18, 2025 at 06:23:45PM +0200, Manuel Giraud wrote:
> "Theo de Raadt" <deraadt@openbsd.org> writes:
> 
> > Manuel Giraud <manuel@ledu-giraud.fr> wrote:
> >
> >> Florian Obser <florian@openbsd.org> writes:
> >> 
> >> > It kind of misses a diff for the man page.
> >> 
> >> Yes I know but I wanted to try first if this could fly.
> >
> > It won't fly becuase we don't know what it does because you didn't
> > document it.
> 
> Ok.  It is an option present in other implementations that permits to
> have multiple command line options in a shebang script.  Here's what is
> said in the linux manpage:
> 
>      -S, --split-string=S
>               process and split S into separate arguments; used to pass
>               multiple arguments on shebang lines
> 
> For example, one could make the following silly script:
> 
> #!/usr/bin/env -S cat -b -e
> Hello World
> 
> The current env will fail because it will try to execvp the complete
> string "cat -b -e":
> 
> env: cat -b -e: No such file or directory
> 
> I wanted to know if this would fly because here I choose to split the
> string beforehand when argv[1] contain any separators.  I kept the "-S"
> for compatibility with other implementations but, in fact, it does
> nothing.

Regardless of -S pros and cons, there is _no way_ you can change the
default behavior of env(1).  That would break many usage patterns just
for the sake of adding a workaround for scripts.

In coreutils or FreeBSD env, -S takes a mandatory argument and only
that argument is split.  If we add -S, we should follow the same
logic.

Excerpt from genv(1):

SCRIPT OPTION HANDLING
     The -S option allows specifying multiple arguments in a script.  Running
     a script named 1.pl containing the following first line:

            #!/usr/bin/env -S perl -w -T
            ...

     Will execute perl -w -T 1.pl

     Without the '-S' parameter the script will likely fail with:

            /usr/bin/env: 'perl -w -T': No such file or directory

     See the full documentation for more details.

Personnally I don't feel strongly about it but I think there is value
in adding -S so that we don't have to write shell wrappers for
non-shell scripts written on other systems (or move those scripts to
genv(1)).

-- 
jca