test$ hg --version
Mercurial Distributed SCM (version 6.1)
(see https://mercurial-scm.org for more information)

Copyright (C) 2005-2022 Olivia Mackall and others
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
test$ hg init
test$ touch a
test$ hg add a
test$ hg ci -d "1970-01-01 00:00:00 +0000" -u testuser -m a
test$ touch b
test$ hg add b
test$ hg ci -d "1970-01-01 00:00:00 +0000" -u testuser -m b
test$ hg log
changeset:   1:952880b76ae5
tag:         tip
user:        testuser
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     b

changeset:   0:d61f66df66f9
user:        testuser
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     a

test$ hg log -r 2
abort: unknown revision '2'
test$ hg log -r 9
changeset:   1:952880b76ae5
tag:         tip
user:        testuser
date:        Thu Jan 01 00:00:00 1970 +0000
summary:     b

test$