Re: Missing documentation "-bash_input"

[Greg Wooledge]

On Tue, Nov 28, 2023 at 10:33:20PM +0000, Klaus Frank wrote:
> sorry, but this is not true, I can clearly see that it exists. It may be an
> distro addition though. Is it specific to ArchLinux?

Here's what I get on Debian:

unicorn:~$ bash -bash_input foobar -c 'read; declare -p REPLY'
bash: -_: invalid option
Usage:  bash [GNU long option] [option] ...
        bash [GNU long option] [option] script-file ...
GNU long options:
        --debug
        --debugger
[...]

I get the same thing if I use a bash that I compiled from upstream source.

If I try --bash_input I get this:

unicorn:~$ bash --bash_input foobar -c 'read; declare -p REPLY'
bash: --bash_input: invalid option
Usage:  bash [GNU long option] [option] ...
        bash [GNU long option] [option] script-file ...
GNU long options:
        --debug
        --debugger
[...]

> Bash source code on GitHub mirror:
> https://github.com/bminor/bash/blob/master/y.tab.c#L3967
> 
> "(--bash_input.location.string) = c;"

That's the pre-decrement operator in C.  Here's the full context for
that snippet:

static int
yy_string_unget (c)
     int c;
{
  *(--bash_input.location.string) = c;
  return (c);
}

It's decreasing the value of bash_input by 1, before accessing it.
It has nothing to do with the presence or absence of "--bash_input" or
"-bash_input" as a command line argument.