CentOS https://github.com/buuren/centos/wiki 7 = 4+2+1 (read/write/execute) 6 = 4+2 (read/write) 5 = 4+1 (read/execute) 4 = 4 (read) 3 = 2+1 (write/execute) 2 = 2 (write) 1 = 1 (execute)