Moto G: how to block/stop an app's notification

settings -> sound & notification -> app notifications -> find the specific app and block.

Mac can't detect/recognize USB external hard drive

A summary of online sulotions:
1. click on a blank area on desktop, Finder -> preferences -> General (tab), check the external drive item to show it on desktop
2. search the "disk utility " and see whether your disk is there
3. My own method: restart your Mac. And it worked.

How to restore deleted repository when using Github desktop

Forum streams too long to read. The simple solution:
1. open the github desktop
2. if you deleted your repository, you should add that folder back
3. you may see that Github desktop actually saved your information
4. click on the branch where you saved all your contents of the folder
5. check your folder on Mac. They should be back.

Comments:
Deleting a folder on Github doesn't mean transferring them into the trash can. It also varies with versions. The correct thing to do is, never try to add to the complexity of this issue. Go back to your Github desktop application and see whether you can retrieve the information. I'd say that I'm so lucky to be able to recover all my scripts. And I learned my lesson: Always back up your important files.