Linux learning should be down-to-earth, training is ok, but study hard. If that trick is not recommended, read a book first. If you are a training institution, you will feel that what you teach is empirical at most. Do it yourself first. Jingfeng is really not recommended, but it is said that the students they train have high salaries, but it seems hard to say after changing jobs. Again, if you want to learn, I suggest reading the free book "This is how linux should learn". Learn before you speak.