Re: Question on updating to 29.1

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 12 Aug 2023 08:08:59 +0200
> From: PierGianLuca <luca@magnaspesmeretrix.org>
> 
> Hi Eli,
> 
> > The Emacs installation method is designed in a way that allows you to
> > have several Emacs versions installed on the same system.  Only one of
> > them, the one you installed the last, is invoked by the name "emacs",
> > but all the others can be invoked by their numbered names, as in
> > "emacs-28.2" etc.  An installed version of Emacs will only be removed
> > if you explicitly run "make uninstall" in the build directory of that
> > version.
> 
> 
> Thank you, this is very useful information. Wouldn't this be useful in the INSTALL files? or maybe it's already there. I might want to keep one previous version just in case, but no other.

This is standard GNU structure of Make targets, every GNU project
follows that.  You can find the list of standard targets in the node
"Standard Targets" of the "GNU Coding Standards" document.

I find no reason to duplicate that information in Emacs, as that would
waste space for no good reason, and will not be discoverable enough to
make the difference anyway.  Stuff that "just works" doesn't need any
prominent documentation in the first place.

> Should I do "make uninstall" for the previous version after I install the new version, or before, or it doesn't matter?

It's up to you.  I personally never uninstall old Emacs versions, but
that's because having them makes it easy for me, as an Emacs
developer, to check how old versions behaved in specific situations
and when did a specific bug start to happen.  Another consideration is
that if you upgrade your system, some old versions might not run
anymore, at which time they are just using up disk space, and should
probably be removed.  (In this regard my hat off to Microsoft, because
I still have a Windows port of Emacs 21.4, built 17 years ago, running
just fine on my current MS-Windows system, after several OS
migrations, whereas Trisquel GNU/Linux, for example, tends to break
binaries compiled with older OS versions upon every significant OS
upgrade.)