Just some PostgreSQL related commands.
Copy a whole database
CREATE DATABASE new_db_name WITH TEMPLATE origin_db_name;
Get list of databases
SELECT datname FROM pg_database ORDER BY datname
Get the size of all the databases
SELECT
t1.datname AS db_name,
pg_database_size(t1.datname) AS db_size
FROM pg_database t1
ORDER BY pg_database_size(t1.datname) DESC;
The same on the command line:
PGPASSWORD=password psql -h 10.11.12.13 -U username -c "SELECT t1.datname AS db_name, pg_size_pretty(pg_database_size(t1.datname)) AS db_size FROM pg_database t1 ORDER BY pg_database_size(t1.datname) DESC;
Get the size of a single database
SELECT pg_database_size('foobar');