1. Chapter 10 File System Security

2. Security Policies security policies are doors maintain a balance between total access and total security UNIX has two default security features: user logins and passwords file and directory protection with permissions default for files Read/Write for User and read only for Group and Other default for directories Read/Write/Execute for User and Read/Execute for Group and Other

3. File System Permissions user - owner / creator of file or directory group - primary group to which owner belongs other - world, everybody else looks at the first set of permissions that match who you are - r w - r - - r - - d r w x r - x r - x

4. Permissions

5. User & Group ID ls -n displays the UID and the GID id displays numeric and alphabetic User ID and Group ID for your Effective User ID (EUID) groups displays all of the groups you are a member of

6. Changing Permissions Syntax $ chmod mode filename The mode portion is made up of three parts: Who -Category you are working with u = user g = group o = others a = all Op - Operator set (=) remove (-) give (+) Permission(s) assigned – Read (r), Write (w) or Execute (x)

7. Changing Permissions - Symbolic

8. Permissions - Octal Mode octal - eight possible numbers in group bits are either on (1) or off (0) 7r w x1 1 1 6r w -1 1 0 5r - x1 0 1 4r - -1 0 0 3- w x0 1 1 2- w -0 1 0 1- - x0 0 1 0- - -0 0 0

9. Changing Permissions - Octal

10. Changing Permissions - CDE Or right click on item

11. Lab 10.2.4 Determining Permissions Lab 10.3.3 Changing Permissions from the Command Line Lab 10.4.1 Changing Permissions from File Manager chapter 10 assessment Labs/Assessment

12. 1. create a script file which will clear your screen, output the current month's calendar, and output the current date Chap 9 & 10 Exercises

13. 1. create a script file which will clear your screen, output the current month's calendar, and output the current date $ vi firstscript type i to get into entry mode in vi editor type clear;cal;date press escape, then colon, then wq! Chap 9 & 10 Exercises

14. 2. now run this script $ firstscript Chap 9 & 10 Exercises

15. 2. now run this script $ firstscript won't work? why not? Chap 9 & 10 Exercises

16. 2. now run this script $ firstscript won't work? why not? because default permissions don't include execute! Chap 9 & 10 Exercises

17. 2. now run this script $ firstscript won't work? why not? because default permissions don't include execute! 3. fix this problem Chap 9 & 10 Exercises

18. 2. now run this script $ firstscript won't work? why not? because default permissions don't include execute! 3. fix this problem $ chmod 755 firstscript Chap 9 & 10 Exercises