Big Review

1. CSI 135 Big Review

2. Why Review? • Some students in this class are still struggling with basic issues and with understanding the context in which we are working • So we need to review what we’ve done so far in class and how it all fits together

3. Basic Unix Commands $ ls $ pwd $ cd $ touch $ mkdir $ rmdir $ rm $ who $ cp $ mv $ date $ cal $ echo $ history $ env $ sort

4. Basic Unix Commands $ ls $ pwd $ cd $ touch $ mkdir $ rmdir $ rm $ who List files Show current directory Change directory Create file or update timestamp Make directory Remove directory (if emtpy) Remove Show who is logged in

5. Basic Unix Commands $ cp $ mv $ date $ cal $ echo $ history $ env $ sort Copy Move (or rename) Show date & time Show calendar Repeat typed text Show previous commands Show user environment Sort lines of characters

6. Basic Unix Commands $ cat $ more $ head $ tail $ wc $ ps Display contents of a file Show file screen at a time Show top of file Show bottom of file Count characters, words and lines Show the running processes

7. Basic Unix Commands $ ls –l -rw------- 1 shsstaff 8876 May 30 2008 my.txt drwx------ 2 shsstaff 512 Mar 13 2006 mydir

8. Basic Unix Commands $ ls -l /usr/bin | egrep 'date|who' -r-xr-xr-x 1 root bin 8552 Jan 5 2000 date -r-xr-xr-x 1 root bin 6240 Jan 5 2000 rdate -r-xr-xr-x 1 root bin 6280 Jan 5 2000 rwho -r-xr-xr-x 1 root bin 13088 Apr 3 2001 who

9. Basic Unix Commands $ ls -ld local lrwxrwxrwx 1 shs staff 14 Nov 3 16:25 local -> /usr/local/bin

10. Basic Unix Commands $ ls –ld .

11. Basic Unix Commands $ ls –ld . drwx------ 61 shsstaff 3584 Nov 3 16:25 .

12. Basic Syntax $ command [options] [arguments] Examples: $ ls–l myfile $ cd/tmp $ cal 10 2011 $ sort –n nums Notice that options are prefaced with hyphens Also, options are optional (thus, their name!)

13. Getting Help $ man <command> $ apropos <word> Examples: $ man ls $ apropos logout

14. Regular Expressions ? Stands for a single character in commands such as ls * Stands for zero or more characters Examples: $ ls ? List all one-character filenames $ ls a* List all files that start with “a”

15. Regular Expressions [abc] stands for any single letter in the list shown (in this case, a, b or c) [a-z] stands for any single lowercase letter [A-Z] stands for any single uppercase letter [a-zA-Z] stands for any single letter

16. Variables $ myvar=11 $ echo $myvar 11 $ favcolor= ”green” $ echo $favcolor green

17. Environment • The env command will show you a list of variables used to create your working environment and their values • For example: USER=csi135b11 HOME=/u/students/csi135/b11

18. Your “dot files” • Files such as the .bashrc_profile and .bashrc files in your home directory on vader are read when you log in and set up your user environment. • Before your dot files are read, however, a system file, /etc/profile, is read first. This file is read by the shell when any user logs in.

19. Your dot files /etc/profile .bash_profile .bashrc

20. The Unix Filesystem jdoe etc msmith bin home / local The Unix filesystem has one root (base) called / usr bin var

21. The Unix Filesystem /home might be a separate file system jdoe etc msmith bin home / local The Unix filesystem may be comprised of multiple file systems mounted into one tree-like structure usr bin var

22. The Unix Filesystem jdoe etc msmith bin home / local /usr/local/bin usr bin Absolute pathname var

23. The Unix Filesystem jdoe etc msmith bin home / local /home/msmith usr bin var Absolute pathname

24. The Unix Filesystem jdoe etc msmith bin home / local local/bin usr bin Relative pathname var

25. The Unix Filesystem jdoe etc msmith bin home / local ../msmith usr bin var Absolute pathname

26. More Advanced Commands • grep match content • awk select fields • cut select characters or fields

27. More Advanced Commands • grepgrep word textfile • awkawk ’{print $2}’ textfile • cut cut –c1-3 textfile

28. Pipes • Using a | to send the output of one command to be the input of another command $ tail myfile | sort $ head myfile | wc –w $ ls | tail -3

29. Redirection • Sending the output of commands to files or to the bit bucket $ tail myfile > newfile $ head myfile >> logfile $ cat dumfile 2> /dev/null

30. Quotes $ echo ”hello, $USER” hello, csi135b11 $ echo ’hello, $USER’ hello, $USER

31. Backticks • Putting text within backticks makes the shell try to interpret the text as a Unix command and execute it $ echo Today is `date`

32. Scripts • Putting Unix commands in a file and making the file executable makes it a script $ echo date > showdate $ chmod 755 showdate

33. Scripts #!/bin/bash echo Hello, $USER echo Today is `date +%A`

34. Arguments $0 name of script $1 first argument $2 second argument $3 third argument $* list of arguments

35. More Advanced Scripts • if/then/else statements • for loops • while loops

36. if/then if test condition then commands fi if [ condition ]; then commands fi

37. if/then/else if test condition then commands else commands fi

38. if/then/else if [ condition ]; then commands else commands fi

39. For loops for number in 1 2 3 do echo $number is a number done

40. While loops while true do commands sleep 5 done

41. Case statements case month in Jan) tail -5 jan.log;; Feb) tail -5 feb.log;; *) echo ”No log available for $month”;; esac

42. File Systems partitions

43. File Systems partitions data blocks

44. File Systems partitions data blocks meta-data (owner, permissions, etc.)

45. File Systems partitions data blocks meta-data (owner, permissions, etc.)

46. File Systems partitions log kjones msmith jdoe var home /

47. File systems • The df command displays a list of the file systems on a Unix system, including how full they are and where they are mounted (i.e., attached to the Unix file system tree) • As a Unix user, you might want to know this if you can’t save a file (no space left on device) • As a Unix systems administrator, you would need to clean up the file system so users can work