When learning Linux system, there may be some difference between "WHO AM I" and "WHOAMI" when they are working, and they are some of themselves, I hope to give you a little help ^ _ ^.
WHO AM i Show users whoami of landing system Show current operations
For example, Login: S021636Passwd: ************
$ su rootpassword: ***********
$ WHO AM IS012636 ---------- (Landing System User) $ WHOAMIROOT ------------- (Now Operation Permissions User)
Hard connection two files point to the same inode, create a file name
Symbolic Link creates a new file, the file describes the path to the file
