Special permissions for files in Linux

1.suid is: Let the ordinary user can perform "only root permission to execute" Special permissions, Sgid "group" ( only valid for binary program )

2.stick bit (paste bit) is: Unless the directory owner and root user has permission to delete it, other users can not delete and modify this directory . (2.1 Sgid useful for binary 2.2 for directories: The user has the RX permission to the directory to enter the directory , the user enters this directory, the effective user group becomes the user group of the directory, If the user has W permissions in this directory, the user creates a file user group that is the same as the directory user Group )

3.sticky bit (paste bit) is: unless the owner and root user of the directory has permission to delete it, other users cannot delete and modify the directory . (for catalogs only)

Finally, after some files have special permissions set, the letters are not lowercase s or T, but the uppercase S and T, which means that the special permissions on this file do not take effect because you have not given it the user's X permission.

Special permissions for files in Linux