Better generic method of finding all installed Postgres versions?

pg_lscluster is great, but it's Debian/Ubuntu specific.

$ realfs=$(df -x tmpfs -x devtmpfs | tail -n +2 | awk '{print $6;}' | xargs)
$ find ${realfs} -xdev -type f -name pg_ctl |& grep -v "Permission denied"

This works on both Ubuntu 18.04 and RHEL 8.3 (the only systems I have access
to), but wonder if there's a Better Way.  (I didn't grep  netstat because
the cluster might not be running.)

Thanks

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