考考你
1. what is the difference between soft link and hard link
2. how to login remote host using ssh without inputing user name and passoword
3. In order to enable user/group quota, which file should be modified first and how? What is soft limit? and hard limit? what is grace period?
4.what is the default editing mode of Bash? In default editing mode, how to cleare screen and what is the result of pressing "Ctrl+P"?
5. how many commands can be used to locate a file, what are they, which is /are the most efficient and why?
If you can not understand all the above, maybe the first thing you need to learn is English.