Answer by willg for How to feed mysql queries from bash

cat <<EOD | mysql [-u user] [-ppassword] [database]
  select 1;
  select 2;
  select 3;
EOD

in your case

cat <<EOD | mysql -u root -p
    CREATE DATABASE IF NOT EXISTS testuser_dev DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
    GRANT ALL PRIVILEGES ON  testuser_dev.* TO  "testuser"@"localhost";
    CREATE DATABASE IF NOT EXISTS testuser_qa DEFAULT CHARACTER SET utf8 COLLATE utf8_bin;
    GRANT ALL PRIVILEGES ON  testuser_qa.* TO  "testuser"@"localhost";
    FLUSH PRIVILEGES;
EOD