[syslinux] correct "--help' options

[Ady Ady]

> Date: Fri, 31 Aug 2012 22:32:18 -0400
> From: gene.cumm at gmail.com
> To: syslinux at zytor.com
> Subject: Re: [syslinux] correct "--help' options
> 
> On Fri, Aug 31, 2012 at 8:46 PM, Ady Ady <ady-sf at hotmail.com> wrote:
> >
> > Hello hpa,
> >
> > When running each ldlinux.sys installer:
> > extlinux
> > syslinux
> > syslinux[64].exe
> > syslinux.com
> >
> > with the "--help" argument, the results are different, depending on
> > the specific installer.
> 
> As each accepts different options.
> 
Yes; I'm referring to the ones in common, such as those in the examples.
 
 
> > Under the Linux-based installer(s):
> > --once=... Execute a command once upon boot
> >
> > while for the others:
> > --once=... -o Execute a command once upon boot
> >
> > Note that the "-o" is missing under Linux.
> 
> It should not show under the syslinux installers (linux/syslinux and
> mtools/syslinux). I believe this is historical as it could also be
> used for --offset.
> 
 Sorry, that makes no much sense to me. It can only lead to confusions.
 "--offset" is "-t", and the "short" common options shouldn't be used
 differently in each installer. Also "--offset" doesn't appear for EXTLINUX.
 All this makes it more difficult for the final user and for documentation,
 and easier to mess up when developing. It also makes the statement "EXTLINUX
 is like SYSLINUX but for mounted fs" more inaccurate.
 
 The only reason would be if "-o" was actually used for "--offset" in
 "recent" stable versions of (the installer of) syslinux, in case it was
 used in some script. Other than that possibility, not using "-o" for one
 installer just invites for problems. The alternative would be not to use
 "-o" in none of the installers.
  
 
> > I haven't tested whether "-o" is actually working or not in any of the
> > installers. It would be convenient to test and unify both:
> > _ the actual behavior of "<installer> -o", and;
> > _ the "--help" screen.
> >
> > A similar example is
> > --directory -d Directory for installation target
> >
> > which appears after "syslinux --help" but not after "extlinux --help".
> > Does extlinux support "--directory"?
> 
> It doesn't need to. That's what the path parameter for extlinux is for.
 I guess I need to experiment with EXTLINUX more, because I don't exactly
 understand the meaning of that.
 
> 
> > In addition to those requests, I'd like to know if there is any specific
> > "logic" for the order of appearance of the options when running
> > "<installer> --help".
> 
> Perhaps libinstaller/syslxopt.c:usage() needs to have the common
> options resorted.
> 
> -- 
> -Gene
 At least "some" kind of logic would make it easier for the final user (who
 needs the "--help" screen). For example (and I also have in mind other
 different possible sorting orders, not just this one, so this is just one
 idea among several), first the options that are common to the different
 installers, and then the specific ones, alphabetically sorted.
 But before re-sorting, the common options should be really common.