The following code logs in to postgres with the psql command, and then alters the password of a user with the alter command.
psql paradocs
alter user paradocs with password 'pgsql_password';
Various commands and sql
\d <table_name> -- oracle desc equivalent, outputs attributes of table
\? -- other commands
UPDATE fat SET field4='200709' WHERE fatid=74528;
select * from fat where field7='LAST' AND field8='FIRST';