Re: Handling options with optional arguments with getopts

[Kenneth Irving]

On Fri, Aug 27, 2021 at 11:33 AM Lawrence Velázquez <vq@larryv.me> wrote:
>
> On Fri, Aug 27, 2021, at 1:20 PM, nigelberlinguer wrote:
> > ‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
> > On Friday, August 27, 2021 4:02 PM, Robert Elz <kre@munnari.OZ.AU> wrote:
> > > XBD 12.2 guideline 7 is:
> > >
> > > Guideline 7: Option-arguments should not be optional.
> > >
> > > That is, if you want to be able to give an option arg, or not give one,
> > > those should be implemented as 2 separate options.
> >
> > It should be noted though, that the POSIX requirement by "Guideline 7"
> > is not guided by actual portability in the technical sense but by a
> > rule written in the POSIX standard.  Perhaps there should be an update
> > to POSIX on what is actually portable or not
>
> https://www.opengroup.org/austin/lists.html
>
> --
> vq
>

> I also wonder whether the "shift" command is used with `getopts`.  I see 
> people use
> the `shift` command when doing their own parsing; and when others use 
> `getopt`.

$  help shift
shift: shift [n]
    Shift positional parameters.
    Rename the positional parameters $N+1,$N+2 ... to $1,$2 ...  If N is
    not given, it is assumed to be 1.
    Exit Status:
    Returns success unless N is negative or greater than $#.

 $  help set
set: set [-abefhkmnptuvxBCHP] [-o option-name] [--] [arg ...]
    Set or unset values of shell options and positional parameters
    Change the value of shell attributes and positional parameters, or
    display the names and values of shell variables.
     ...



-- 
Ken Irving