Answer from doug, somewhat extended:
/snap/*
is read-only and snaps are mounted there. The reason for this is that snapd
allows you to roll back to an older version of a given snap, that's why it keeps multiple versions. Calling snap remove
will remove them all from the system again. There is a r/w location for snaps, but that's unrelated. https://developer.ubuntu.com/en/snappy/guides/garbage needs an update, but it explains the general concept.
Rolling back is done using snap revert
:
daniel@daydream:~$ snap revert --help
Usage:
snap [OPTIONS] revert []
The revert command reverts the given snap to its state before the
latest refresh. This will reactivate the previous snap revision, and
will use the original data that was associated with that revision,
discarding any data changes that were done by the latest revision. As
an exception, data which the snap explicitly chooses to share across
revisions is not touched by the revert process.
Application Options:
--version print the version and exit
Help Options: -h, --help Show this help message
daniel@daydream:~$