Week Two Agenda

2. Week Two Agenda Announcements Link of the week Use of Virtual Machine Review week one lab assignment This week’s expected outcomes Next lab assignments Announcements Break Out Problems Upcoming Deadlines Lab assistance, questions and chat time

3. Announcements Class participation Class participation is an essential element in this class. Many times a student’s final grade borderlines the next highest letter grade. The course instructor has the authority to assign or not to assign the next highest final grade when the score is within .5 and 1 points of the next highest letter grade. Convince me professionally, that you want an “A” in this course.

4. Link of the week • The link below lists most all operating systems that are available. • http://dmoz.org/Computers/Software/Operating_Systems • The link below has tabs for books, posters, software, and tools • http://www.javvin.com/unix-like-poster.html • Definition of Operating System (OS) • Common operating systems discussed in this class will be: UNIX, Linux, and HP-UX • Basic tasks performed by an operating system • Control and allocate memory for processes • Prioritize system requests for the CPU • Control input and output transmissions to and from devices • Facilitate networking and support file system management

5. Link of the week Services Operating System (OS) perform • Process management • Memory management OS coordinates various types of memory • File systems • Networking • Graphical user interface (GUI) and command line • Device drivers • Security • Internal management • External management

6. Use of the Virtual Machine Knoppix features • Use the sftp command to move a file from Knoppix software to the cs.franklin.edu (Einstein) machine using VMware software Open two Konqueror windows Enter the ftp protocol sftp://dandrear@cs.franklin.edu/export/home/dandrear in one screen Open a Konsole screen and create a file to transfer to the cs.franklin.edu machine.

7. Review week one lab assignment Basic vi editor commands. vi test_file.txt ^ (place cursor on beginning of line) $ (place cursor at end of line) o (insert text - alpha character) cw (change an entire word in a file) Esc key (exit insert mode) :wq! (save text entered in file) :q! (quit without saving changes)

8. Review week one lab assignment Less command q (terminates pagination) Enter or Return key (advance one line) Space bar (refresh entire screen) Location of weekly Power Point presentations: http://cs.franklin.edu/~dandrear/itec400/Winter_2011_ Franklin_Live_Presentations/ File format: Week_Two_2_ppt.ppt Week_Two_2.pptx

9. Review week one lab assignment if [ ] then Action statements fi while [ ] do Action statements done for file_name in * do Action statements done

10. Review week one lab assignment #!/bin/ksh NUMBER=$1 # One argument must be provided, otherwise don’t execute if [ …] then …… Action statement(s) exit ….. # The value of the command line argument can’t # be less than or equal to zero. elif [ …] then ……Action statement(s) exit ….. fi

11. Review week one lab assignment # Integer value must be greater than zero while [ ……… -gt 0 ] do printf $variable # If the value of the argument is greater than one, insert a comma after the integer if [ ………… -gt 1 ] then printf ", " fi # Decrease the value of NUMBER by one with each iteration NUMBER=$(($.................. - 1)) done printf

12. Review week one lab assignment ERROR1="error: can only use 0 or 1 arguments.\nusage: maxlines.sh [directory]" ERROR2="error: argument must be a directory.\nusage: maxlines.sh [directory]\n" # Verify that more than one command line argument doesn't exist. if [[ $# -gt 1 ]] then printf "$ERRORX" exit 1 fi # Default variable setting DIR="."

13. Review week one lab assignment # Case #2. # The number of arguments on the command line equals one. if [[ $X -eq 1 ]] then # Is the command line argument a directory? if [[ -X $1 ]] then # Assign the command line argument to the variable, DIR="$X" else printf "$ERRORX" exit 1 fi fi

14. Review week one lab assignment #All cases are processed with the following code. # Change directory to the indicated variable content. cd $XXX # Assign file name with highest number of new lines to the variable FILE. FILE=$(wc –X `ls` 2>/dev/XXXX | sort –X X | tail –X X | head –X X) # Print statement for all cases. printf "File `echo $FILE | awk '{print $X}'` has the maximum lines with `echo $XXXX| awk '{print $X}'` lines.\n" exit 0

15. Review week one lab assignment Case #1: ./printnum.sh <numeric value> /~dandrear/itec400/homework Case #1: ./maxlines.sh or ./maxlines.sh . /~dandrear/itec400/homework printnum.sh maxlines.sh Case #2: ./maxlines.sh /bin cat chmod cp, … etc

16. Review week one lab assignment man (uses the “less” command for pagination) ls –l ps ls -a cut –c 1-7 wc -l $# date exit 0 exit 1 NUMBER=$2 echo $NUMBER less

17. Review week one lab assignment cp file1 file2 mv file1 file2 rm file_1 rmdir dir_1 clear head tail who myArray[1]=$1 more ps –ef

18. Review week one lab assignment grep find ls mkdir cd $1 $1, $2, $3 cat <file name> chmod <permission> <file name>

19. Review week one lab assignment sleep <number of seconds> diff <file name> <file name> cd <directory> sort <file name> umask umask -S who who am i

20. Weeks 2 and 3 expected outcomes Upon successful completion of this module, the student will be able to: • Create scripts using shell variables and program control flow. • Use man page system and find script tools. • Use redirection and pipes to combine scripts and executables.

21. Next lab assignment In a Unix environment, the commands you enter are executed by a program called the "shell". The user must select a command shell to communicate with UNIX. Examples are Korn, Bourne, and C Shell. One of the things that makes the UNIX operating system so flexible is its layered design. At the core is the hardware. The hardware is surrounded by system software that most users never interact with called the kernel . The kernel is surrounded by programs (often called utilities) such as cat, date, and diff commands that perform specific tasks. A shell program communicates with these utilities and the kernel with text type information.

22. Next lab assignment A shell program enables a user to interact with computer resources, such as programs, files, directories, and devices. Shells allow users to interact on a system interactively as a command interpreter. When acting as command interpreter, the shell is the interface between the user and the system in a real time environment.

23. Next lab assignment Most shells are used as a programming language. Users can combine command sequences to create new programs. These programs are known as shell scripts. Shell scripts automate the use of the shell as a command interpreter. The first line of any script must begin with #!, followed by the name of the interpreter. Examples: #!/bin/ksh #!/bin/bash #!/usr/bin/perl Demonstrate: cat /etc/shells echo $SHELL

24. Next lab assignmentConcentric Circle Relationship

25. Next lab assignment drwxrwxrwx permissions (directory) -rwxrwxrwx permissions (file) lrwxrwxrwx permissions (symbolic link) -rwx------ 2 dandrear faculty (hard link) crw------- 1 root root 14, 4 Jun 24 2004 audio brw-rw---- 1 root disk 29, 0 Jun 24 2004 aztcd The exit command has a return value. 0 indicates normal exit 1 indicates failed exit The return value of a command can be used with conditional or iteration commands.

26. Next lab assignment Exit command Allows you to exit from a program, shell or log you out of a Unix network. The exitcommand may be used to terminate a script, just as in a C program. It can also return a value, which is available to the script's parent process. Every command returns an exit status (sometimes referred to as a return status ). The exit command values range is from 0-255. 0 indicates normal exit 1 indicates failed exit

27. Next lab assignment Pipe Command Users can connect the standard output of one command into the standard input of another command by using the pipeline operator (|). Demonstrate general commands: ps -ef ps –ef | wc –l ps –ef | awk ‘{print $2}’ ps –ef | grepdandrear ls –l | cut –c1-3 who –b (time of last system boot) who –d (print dead processes) who –r (print current run level) .

28. Next lab assignment File Descriptor A process associates a number with each file it has open. This number is called a file descriptor. When you log in, your first process has the following three open files connected to your terminal. Standard input: Filedescriptor 0 is open for reading. Standard output: File descriptor 1 is open for writing. Standard error: File descriptor 2 is open reading.

29. Next lab assignment Manual (man) Command Linux command documentation is known as “man”. Each page is a self-contained document. The Manual sections are split into eight numbered sections: 1 General commands. 2 System calls 3 C library functions 4 Special files (usually devices, those found in /dev) and drivers. 5 File formats and conventions 6 Games and screensavers 7 Miscellaneous 8 System administration commands and daemons

30. Next lab assignment Grep Command The grep command searches the named input file(s)for lines containing a given pattern. Normally, each line found is reported to standard output. Demonstrate: grep text ~dandrear/Winter08_solutions/foobar grep pattern foobar_1 grep pattern *

31. Next lab assignment Find Command The find command lists all pathnames that are in each of the given directories. Demonstrate: find / -type d –print find ~dandrear –type d -print find . –print find / -name foobar

32. Next lab assignment Redirections Many UNIX commands take text-like input and/or produce text-like output. It's sometimes useful to be able to control where the input comes from and output goes (via redirection), or even pass the output from one command to another's input (via pipes).

33. Next lab assignment Redirection (cont) Redirect the standard output of a command to a file. date > /tmp/date_saved Redirect the standard input of a command so that it reads from a file instead of from your terminal. cat < ~dandrear/Summer2010_solutions/test.txt Append the standard output of a command to a file. cat foobar_2 >> foobar_1

34. Next lab assignment Coding and Testing Process Code one small script function at a time. Test that function before adding more code to the script. Program coding is an iterative process (code,test,code,test,code,test, …).

35. Break Out Problems • ps | wc –l • who | awk ‘{print $1}‘ | sort –u | wc –l • ps –ef | awk ‘{print $1}’ | sort –u | wc –l • sort –r names.txt • ps –ef | awk ‘{print $9, $1}’ • find /bin -name gzip • find /etc -name motd • > newfile • rm newfile • date | cut –c12-19 • cp test_data.txt ~dandrea/temp • mv test_data.txt ~dandrear/temp • printf $NUMBER

36. Upcoming Deadlines • Lab Assignment 2-1, Simple Shell Scripting, due May 15, 2011. • Lab Assignment 3-1, Advanced Scripting, due May 22, 2011. • Read Chapters 1 and 2 in Essential System Administration text. • Read Module Two listed under the course Web site • Did everyone receive a Shell Quick Reference document and script logic for Lab Assignment 2-1?

37. Lab assistance, questions and answers • Questions • Comments • Concerns • After class I will help students with their scripts.