1. November 5, 2015CIS 118 Intro to UNIX What’s a Unix? Unix is an Operating System Designed for high-traffic usage Many variants –Linux, BSD: free versions Spelled either Unix or UNIX

2. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

3. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

4. November 5, 2015CIS 118 Intro to UNIX Multi-Computer, Multi-User Servers Clients

5. November 5, 2015CIS 118 Intro to UNIX The Shell Person Operating System SHELL User types commands into shell Run program Shell translates commands to machine code 1100101 0110010

6. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

7. November 5, 2015CIS 118 Intro to UNIX Interesting Commands Communication –write –mail –talk Useful –man –who –date –cal Printing –lpr –printer rm# file Network –ping –traceroute –nslookup –hostname

8. November 5, 2015CIS 118 Intro to UNIX E-mail Commands mail: read/send mail pine: read mail forwardmail: forward mail blockmail: block mail procmail: proc[ess] mail

9. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

10. November 5, 2015CIS 118 Intro to UNIX What’s on your server? List users online –users –who –last [user] –finger [user] FAS-specific –ph [full name] –rwho [user] What are people doing? –w –ps [aux] Managing your own processes –fg/bg –kill [process #]

11. November 5, 2015CIS 118 Intro to UNIX Communicating on UNIX write user[@machine]: send a one- way message talk user[@machine]: have a conversation mesg [y | n]: let people talk to you

12. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

13. November 5, 2015CIS 118 Intro to UNIX Hierarchical File System /home/c/d/cduan

14. November 5, 2015CIS 118 Intro to UNIX Remote Home Directories home05 home06 home07 is01 is02 smtp webmail

15. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

16. November 5, 2015CIS 118 Intro to UNIX File System Commands Browsing commands File Manipulation Commands File Viewing/Editing Commands

17. November 5, 2015CIS 118 Intro to UNIX File Browsing pwd print working directory % pwd /home15/c/d/cduan cd change directory cd.. up 1 directory % cd /usr/bin % pwd /usr/bin ls list files ll “long” listing % ls file1 file2 file3 file4 file5 file6

18. November 5, 2015CIS 118 Intro to UNIX File Manipulation mv: move file(s) –mv file1 file2 rename file1 to file2 –mv [file…] dir move files to directory cp: copy file(s) rm: remove file(s) mkdir: create a directory rmdir: remove a directory

19. November 5, 2015CIS 118 Intro to UNIX File Viewing/Editing cat, more, less, head, tail: view (parts of) files grep word [file…]: find words in files vi: edit files (see tutorial) –Or use that pico program

20. November 5, 2015CIS 118 Intro to UNIX Using UNIX Basic Concepts Common Commands Multi-User Functions File System –Structure –Commands –Security UNIX>_

21. November 5, 2015CIS 118 Intro to UNIX File System Security Problem: multiple users, one machine 1.How do we keep data private? 2.How do we make data public? 3.How do we make data partially public?

22. November 5, 2015CIS 118 Intro to UNIX File System Security Solution: UNIX permissions scheme Three levels of people –Self, group, others Three levels of protection –read, write, execute

23. November 5, 2015CIS 118 Intro to UNIX File Permission Types LevelFor FilesFor Directories readAble to read file contents Able to list files in directory writeAble to modify file contents Able to create/ remove files executeAble to run file as a program Able to use files in directory

24. November 5, 2015CIS 118 Intro to UNIX User Permission Levels Self: yourself Group: members of pre-defined system groups (student, ua, etc.) –Generally not treated specially World: every user on the system Root can read/write everything!

25. November 5, 2015CIS 118 Intro to UNIX Viewing File Permissions: ll -rwxr-xr-x 1 cduan ua... self group worldownergroup read write execute No write permission for world

26. November 5, 2015CIS 118 Intro to UNIX Changing Permissions: chmod LevelSelfGroupWorld read444 write222 execute111 + chmod 755 [file…]

27. November 5, 2015CIS 118 Intro to UNIX Common chmod Values Private file Private directory Public file Public directory Public directory, no listing files 600 700 644 755 711

28. November 5, 2015CIS 118 Intro to UNIX Using UNIX: Final Remarks Where to get help –man pages –Internet –User Groups