mariadb
DatabasesPackage: mariadb-client
MariaDB's interactive client, the counterpart of psql. mariadb -e runs a query from a script; SHOW DATABASES and SHOW GRANTS are the first two things to look at on an unfamiliar server.
What its options do in the lessons
From the same glossary the lessons render under their commands, so the two cannot disagree.
mariadb -e- Runs one query and exits.