On 2016-01-21 01:25 +0000, Rainer Weikusat wrote:

Rainer> That's a LSB invention. It's a grotesque travesty as it uses
Rainer> 'magic comments' to embed a declarative mini programming
Rainer> language in an init script which is only ever used when
Rainer> modifying the runlevel configuration. Comments are supposed to
Rainer> be used for relatively short, free-style documentation embedded
Rainer> in code, not for interpretation by programs.

Ian> There's precedent for this - the magic shebang lines perl, tcl, guile
Ian> etc. use to get their grubby hands on a script that is masquerading as a
Ian> plain shell script.

Rainer> The kernel uses #! as two-byte magic number to mean 'whatever follows
Rainer> that is the interpreter supposed to interpret this file'[*]. It doesn't
Rainer> execute scripts. Hence, it doesn't define 'scripting language syntax
Rainer> elements'.

To be clear, in the paragraph you've quoted I was _not_ talking about plain
shebangs such as

#! /usr/bin/perl -f

#! /usr/bin/tclsh

(although then I was, in the next paragraph which you haven't quoted).
Rather, I had in mind the serious contortions scripts used to go to
when, for some reason, they _didn't_ rely on the kernel for executing
the interpreter. Even today, the perlrun(1) manpage half-recommends
this:

    #!/bin/sh
    #! -*-perl-*-
    eval 'exec perl -x -wS $0 ${1+"$@"}'
        if 0;

Now _this_ may in fact be a travesty :-)

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