Linux Setup file directory permissions, four-digit directory permission definitions

RWX (1) rwx (2) rwx (3)
1: Owner 2: Owning Group 3: other users
R: Read
W: Write
X: Execute
Table of Contents: R (can see how many things are in the directory) W (can add, remove, and modify the familiar contents of the directory) x (Open Directory)
File: R (can view the specific contents of the file) W (can add, delete, and modify the contents of the file, but cannot delete the file itself) x (runnable file, generally used for executables)
Hidden privileges: SUID (4), SGID (2), Sbit (1)
RWS (1, owner) RWS (2, affiliated group) RWT (3, other users)
1: Even if not the file owner can temporarily own the rights of the file owner
2. What is created in the directory that owns this attribute, belongs to the group that belongs to this directory, has nothing to do with the creator of the object
3, in the directory with this attribute created, in addition to root and creator itself, no one can delete
When chmod, the hidden permission is written in the first bit

Linux Setup file directory permissions, four-digit directory permission definitions