1. Basic permissions
Basic permissions are divided into r w x
2. Permission details
r : read read permission------->4
w : wirte write permission------->2
x : execute execute permission----->1
3. Permission description
A total of nine bytes, divided into three segments
rwx rwx rwx
For the owner For the group to which they belong For other users
4. Modify permissions
chmod 777 /home/admin/test