Re: Bash 5.1: Make shell_script_filename available to startup files

[Marc Aurèle La France]

On Tue, 2 Feb 2021, Chet Ramey wrote:
> On Mon, 1 Feb 2021, Marc Aurèle La France wrote:

> > Currently, only the script's arguments are passed as positional
> > parameters.  For compatibility reasons, $0 cannot be used to also pass the
> > script's filename, so I'm creating a new BASH_SCRIPT variable instead.

> I'm interested in use cases for this feature.

Well, I'll start with the optics, a.k.a. completeness/consistency 
argument.  It makes little sense to pass the script's arguments, but not 
its name.  Using $0 for this would have been even more consistent, but 
that's crying over spilt milk.

I'm currently using this to greatly reduce code duplication in a framework 
that will eventually allow me to...

- Rebuild my system from source, complete with local changes, but without
  the distribution fluff I still have left;
- Keep it up date; and
- When the time comes, move it to different hardware.

... all with much less pain than is currently necessary.

To reduce duplication and maintenance effort, I want everything 
centralised, instead of the current messy patchwork, including, but not 
restricted to, my interactive use of bash.  Currently, I set BASH_ENV 
system-wide which means all scripts that start with "#! /bin/bash" (but 
not "#! /bin/sh") inherit those settings.  However, not all scripts need 
all settings, so to keep things clean, I'm using $BASH_SCRIPT to 
classify/differentiate them.

Yes, I could have all such scripts source a file when they start.  But 
isn't that just another startup file?  And duplication.  Or pass something 
through $1;  again duplication.  BASH_SCRIPT is a more elegant solution 
and doesn't require any intervention from the named script.

If I end up carrying this as a local change, that's fine too.  It 
wouldn't be the first time.

Thanks.

Marc.