uninstalling an old version

[Bob Tennent]

 >|
 >|    Might tlmgr remove --all or the above have removed the
 >|    symlinks in /usr/local/bin?
 >|
 >|It is supposed to, yes.

Karl: Because Reinhard and Norbert suggested otherwise, I
tried myself (without spurious PATH entries and envvars).
After installing basic schemes of TL-2019 and TL-2020 with
symlink settings on, I used the 2019 tlmgr to remove -all.
This removed almost everything under /usr/local/texlive/2019
but did *not* remove symlinks, instead generating error
messages of the form

not removing /usr/local/* , not a link or wrong destination!

which is good news. 

So what happened to me to inspire this thread? I'm not sure
but presumably it was the spurious PATH entry or envvar
setting.

Sorry for the noise.

Bob T.