Where to put the assignment of global environment variables

[Volker Wysk]

Am Donnerstag, dem 15.09.2022 um 10:40 +0200 schrieb Oliver Grawert:
> hi,
> Am Donnerstag, dem 15.09.2022 um 08:54 +0200 schrieb Volker Wysk:
> > Am Dienstag, dem 13.09.2022 um 19:42 +0200 schrieb Oliver Grawert:
> > > hi,
> > > Am Dienstag, dem 13.09.2022 um 16:01 +0200 schrieb Volker Wysk:
> > > 
> > > > looks more like a system wide thing.
> > > 
> > > right, and this is what you normally set in /etc/environment, which
> > > is
> > > the systems "environment for global variables read during boot" 
> > > (i guess this is why peter calls it the "boot environment" :) ) ...
> > > 
> > > so adding your snippets to /etc/environment.d/ is the exact right
> > > thing
> > > here to do ... 
> > 
> > So, when I have something like
> > "PATH=$PATH:/usr/local/lib/mercury.../bin"
> > in there, will the "$PATH" be expanded - or will I have "$PATH"
> > instead of
> > "/bin:/usr/bin:/sbin:...", and the system won't be able to boot any
> > longer
> > ..?
> 
> if you put it properly into an /etc/environment.d file, it will be
> processed after the /etc/environment file (which you should not edit)
> ... that file contains the PATH your OS installer created and the PATH
> variable from there will already be set when your file snippet in the
> .d directory is processed ... so if all done properly like above (i.e
> with "PATH=$PATH:/usr/local...", your PATH will just be enhanced with
> the additions you put in there.

Okay, thanks. That's what I wanted to know.

> 
> > 
> > > and indeed, this environment applies to the whole system, which
> > > includes your services and daemons, so it is only read on boot
> > > pretty
> > > much as the very first thing when switching from the initrd to the
> > > rootfs ... 
> > 
> > Read on boot by a shell (as a shell script), or how will it be
> > interpreted?
> 
> by /sbin/init usually (which is systemd in recent ubuntus), if it would
> be interpreted by a shell only, it would also only apply to that
> specific shell (but for this you have /etc/profile (and the respective
> .d directory and should not use /etc/environment). /sbin/init sets the
> variables globally, so services, GUI apps and other executables can use
> them even when not started from inside a shell.

So, there is no shell involved, until you log in? I didn't know that. Thanks
for the explanation.

Bye, Volker