1. Permissions may be changed later by users and programs using chmod . 2. The chmod numerical format accepts up to four octal digits. 3. :: chmod 700 just gives them file permissions no? 4. This is shown in the demonstration below as the " chmod ug + s" 5. Thus Chmod 's proposal is the best. 6. The combination of these three components produces a string that is understood by the chmod command. 7. *For question 2, we have an article on chmod that explains all the options. 8. Most implementations of the chmod command also support finer-grained, symbolic arguments to set these bits. 9. The chmod command is also capable of changing the additional permissions or special modes of a file or directory. 10. Moreover how does one manipulate it-it's not something I've set or unset with chmod .