Agenda

ITEC400 Week OneRobert D’Andrea

AgendaIntroductionAdministrative AnnouncementsLink of the WeekExpected OutcomesThis Week’s TopicsNext Week’s Lab AssignmentBreak Out ProblemsUpcoming DeadlinesLab assistance, questions, and chat time

IntroductionInstructor

Professor Bob D’AndreaSoftware Engineer Instructor at Franklin University since 2004Home phone No. 614.898.0457Cell No. [email protected]

Program Chair of Information SecurityMr. Todd WhitakerPhone # [email protected]

Administrative AnnouncementsInstructor commitment

Respond daily to student emails.Post student midterm and final exam status on the

course web page folder after each exam has been received from the Student Learning Center (SLC).

Office hoursMonday through Friday: 9:00 AM – 6:00 PMSaturday and Sunday: 12:00 PM – 6:00 PM

Personalized Adobe Connect session can be scheduled on demand by a student needing individual assistance.

Administrative AnnouncementsCourse Web SiteRead the Class Communication section?

AttendanceEmail and/or call me if you are unable to attend class. Otherwise, you will be marked “Not Present” and you will receive an email notice from Franklin University.

cs.franklin.edu serverEveryone will need a login to access the cs.franklin.edu machine. Putty is the prescribed open source interface for this class. You will use putty to access the cs.franklin.edu machine. All student lab assignments will be tested under your /export/home/$USER/itec400/homework directory.

Administrative Announcements

Recorded Franklin Live SessionsEach week, a Power Point presentation is recorded under the following directory:http://cs.franklin.edu/~dandrear/itec400/Winter_2016_Unix_Presentations

Franklin Live file name formatThe naming convention used for the weekly Power Point files is listed below.-rwx---r-x 1 dandrear faculty 1274880 Sep 7 11:08 Week_One_1_UNIX_ppt.ppt-rwx---r-x 1 dandrear faculty 395026 Sep 7 11:07 Week_One_1_UNIX.pptx

The Power Point presentations are available on Monday mornings for printing and/or review prior to the online session. The recorded presentation could contain slight variations from the actual class version.

Administrative AnnouncementsEmail format for completed lab assignments

Email a notification when an assignment is completed and ready to be graded. The “Subject” line of your email notification should contain the following information and format:

<User name> <Section Number> <Lab Assig 1-3>Example: dandrear V1WW Lab Assign. 2-1

Email format for questions<User name> <Section Number> <Question(s)>

Example: dandrear V1WW Question(s)Scripts and text file suffix

All scripts and text files shall end with the proper suffix (e.g. ,sh, .pl, .txt and .cgi).Homework assistance

Do not solicit help from the Internet for lab assignments. If caught soliciting assistance on the Internet, Franklin University will take action against you.

Administrative AnnouncementsDrop Box

All lab assignments must be submitted to the Drop Box. The Drop Box is located under your myFranklin course web page “Course Communication” category.

Student drop box documentation link is listed belowhttp://online.franklin.edu/forms/StudentDropBoxManual.doc/export/home/<user name>/itec400/homework

The homework directory is where your scripts and text files will reside for grading.

Administrative AnnouncementsTurnitin.com Assignments

The Light Directory Access Protocol (LDAP) and Public Domain/Open Source lab assignments must be submitted to Turnitin.com. Your report will be verified by Turnitin.com for author originality. If Turnitin.com indicates that your percentage of originality is 45 percent or greater, I will not grade the paper. I will recommend that you seek assistance from the Student Learning Center (SLC). See the Announcement folder for the turnitin.com login information.

Administrative AnnouncementsVMware software

The Knoppix software can also be downloaded from the course web page or from the following link: http://cs.franklin.edu/~blackbue/Knoppix-VM-setup.zip

Creating scripts using Knoppix softwareftp from your Knoppix software to cs.franklin.edusftp://[email protected]/home/dandrea

http://cs.franklin.edu/~blackbue/Knoppix-VM-setup.zip

Link of the weekOpen Source Software◦http://en.wikipedia.org/wiki/Open_source◦http://freshmeat.net◦http://sourceforge.net

http://en.wikipedia.org/wiki/Open_source

http://freshmeat.net/

http://sourceforge.net/

Link of the weekOpen Source Software

Definition of open source software.Distributed in source code formatDeveloped in a public, collaborative mannerSoftware is free of chargeAllows anyone to apply modifications to the

software.Who benefits from open source products?

Course expected outcomeUpon successful completion of this course, students will be able to:Create non-trivial shell scripts. Perform appropriate UNIX System Administration tasks. Compose non-trivial scripts using Perl programming language. Distinguish the roles of Linux and Open Source software. Incorporate the make utility appropriately within programs. Create an open source presentation of your choice.Create a CGI script

UNIX Operating SystemUNIX comes in a variety of constantly changing

flavors (SUNOS, HP-UX, BSD and Solaris, just to name a few). Each of these UNIX types will have small variations from all of the others. This may seem a bit discouraging at first, but in reality each version of UNIX has more in common with all of the other software versions than differences. For instance, the “ls” command will list the current directory in any UNIX environment. The changes or semantics local to any particular brand of UNIX should be explained in the manual pages that come with that particular version of software.

UNIX Operating System

The purpose of this explanation is not to explore the differences between UNIX flavors, but rather to assure you that their base lines are all equivalent.


The UNIX operating system comes with many commands that allows the user to interact with their computer. UNIX commands are simply programs that are executed when called on. The usual place for the storage of these commands is the /usr/bin directory. The commands available on a particular machine may vary. There is a set number of standard commands that come with a UNIX system, but there is no limit to the number of commands that can be made available on a system.


UNIX, Linux, and HP-UX are all operating systems. The design of an operating system is to coordinate and apply the various parts of the computer -- the processor, the on-board memory, the disk drives, keyboard, video monitors, and mouse to perform useful tasks. The operating system is the central most software program in the machine. It is the mechanism that connects all the internal and external components with administers, programmers, and system users.


The UNIX operating system gives a computer certain recognizable characteristics. However, it would be difficult to distinguish between two different computers, if they were loaded with the same operating system. If you took two identical computers and installed different operating systems on each of them, their differences would be apparent to the observer.


UNIX was created in the late 1960s, the initial effort was to provide a multiuser, multitasking system for programmers to use. The philosophy behind this design was to keep it simple, yet powerful with utilities and write portable code which accessed a network.

The UNIX operating system is made up of three components: The kernel, standard utility programs, and system configuration files.


KernelThe kernel is a core computer program

component of the UNIX operating system. Basically, the kernel is a software program that is loaded into memory when the machine is turned on. The kernel is a memory resident control program. It controls the allocation of hardware resources from the time the machine is turned on until the system is shutdown. The kernel knows what hardware resources are available (like the processor(s), the on-board memory, the disk drives, network interfaces, etc.), and it has the necessary programs to talk to all the devices connected to it. In summary, the kernel is a fundamental part of a modern computer's operating system.


KernelWhen a computer program makes requests of the

kernel, the request is called a system call. Various kernel designs differ in how they manage system calls and resources. For example, a monolithic kernel executes all the operating system instructions in the same address space in order to improve the performance of the system. A microkernel runs most of the operating system's requests in the background in user space, to make the operating system more modular and, therefore, easier to maintain.


General kernel functions performed are: • Managing the machine's memory and allocating

it to each process. • Scheduling the work done by the CPU so that the

work of each user is carried out as efficiently as is possible.

• Accomplishing the transfer of data from one part of the machine to another

• Interpreting and executing instructions from the shell

• Enforcing file access permissions



Standard utility programsThe standard utility programs include utilities

like diff, which compares the content of two files, and other more complex utilities that communicate with the operating system.

UNIX Operating SystemSystem configuration files

The system configuration files are read by the kernel, and many of the standard utilities to configure the initial settings for some computer programs. Configuration files are used for user applications, server processes, and operating system settings. The files are normally written in ASCII or UTF-8, depending on the operating system. They are often referred to as simple databases.

UNIX provides several hundred utility programs, often referred to as commands.

•Editing•File maintenance•Printing•Sorting•Programming support•Online information


User access to a systemLogging into a UNIX system requires two pieces

of information: a user name, and a password. After a user name and password have been authenticated and accepted, a UNIX system shell is created for them to use. The shell’s prompt is usually displayed at the cursor’s position on your screen. In order to get work accomplished, you enter commands at this prompt. A shell program is a command interpreter; it takes each command or combination of commands and passes them to the kernel to act on. It then displays the output from this operation on the screen. There are usually many shells available on a UNIX system, each with its own unique set of capabilities.


The shells found on the cs.franklin.edu (Einstein) machine are:

/bin/sh/bin/bash/bin/ksh/bin/tcsh/bin/cshThe shell is probably the user’s most important

program on a UNIX system. The shell is the interface between you and the UNIX operating system, and the man-in-the-middle, the kernel.


Shell scripts are plain-text files, so you must create them using a text editor. A shell script begins with a line at the top of the file that identifies the preferred shell to be executed, as follows:#!/bin/sh#!/bin/bash#!/bin/ksh

The first two characters are a special syntax that tells the UNIX-like kernel that this is a script and to use the rest of the line as a pathname to the program that’s to interpret the script. This line is sometimes referred to as the shebang, hash bang, or pound bang line.


On most systems, /bin.sh is a symbolic link that points /bin/sh.


What is a shell?Shell programs are designed to fit a specific

concept. They accept a command, interpret the command, execute the command, and then possibly wait for another command. The shell displays the “prompt” to notify the user that it is ready to accept another command.


Putty Interfacelogin as: dandrearAccess [email protected]'s password:Last login: Sun Sep 6 20:31:02 2015 from 10.0.6.166Red Hat Enterprise Linux Server release 6.0 (Santiago) ************This server is subject to Franklin University Use Policy. You may reviewthe Use Policy with the command "UsePolicy". ************To be informed of position postings or internship opportunities, subscribeto the discuss listserv associated with your major (CS, ITEC, MIS, WEBD,or MSCS). You can do that from http://listserv.franklin.edu.

If you run into difficulty, contact Jane Sieberth, [email protected]. ***************/export/home/dandrear>


When you complete the coding of your script, you will want to change the permissions to make it executable. The chmod command should be used as follows:

chmod 705 printnum.sh

After making the script executable, execute your script by typing ./ to tell UNIX-like operating systems to run the script in the current directory, rather than search the PATH variable. If you fail to find the script, it can always be executed by running the shell program followed by the script name, as bash printnum.sh


The shell program recognizes a limited set of commands, and must be given commands in a way that it understands. Each shell command consists of a command name, options, and arguments that are separated by white space. Similarly to writing a sentence where it must contain a subject, a verb, and white space to be a valid. The basic shell command line is:

command name [-options] [arguments]

UNIX Operating SystemThe command name is the name of the program

you want the shell to execute. The command option usually is prefixed with a hyphen, which allows you to alter the behavior of the command. The argument position is the name of directories, files, or programs that the command needs to access.

The shell program is executed by the UNIX kernel for you. A UNIX program is referred to as a process while the kernel is executing it. The kernel can execute the same shell program or any other program simultaneously for many users on a UNIX system, and each executing copy of the program is an individual process.


Many basic shell commands are small subroutines built into the shell program. The commands that are not built into the shell require the kernel to start another process to execute them.

When a non-built-in shell command is executed, the shell requests the kernel to create a new sub-process called a process, to perform the command. The child process lives long enough to execute the command. The shell waits until for the child process completes before it accepts the next command.


A shell is an entity that takes input from the user and deals with the computer rather than have the user deal directly with the computer. If the user had to deal directly with the computer they would not get much done as the computer only understands strings of 1's and 0's. While this is a bit of a misrepresentation of what the shell actually does, it provides a rough idea that should cause the reader to be grateful that there is such a thing as a shell to interface with.


A good way to visualize a shell programWhen a person drives a car, they don’t have

control of every detail that goes into making the engine run or the electronic system or the braking of the vehicle. All the user (or driver in this example) needs to know is that “D” means drive and that pressing or releasing the accelerator pedal will make the car go faster or slower. The dashboard would also be considered part of the shell, since pertinent information relating to the user's involvement in operating the car is displayed there. Pretty simple, huh.


In fact, any part of the car that the user has control of while operating the car would be considered part of the shell. The idea of what a shell is should be clearer now. It is a program that allows the user to use the computer without him or her dealing directly with it. It is in a sense a protective layer that prevents the user and computer from coming into contact with one another.


What is parsing?To parse a command line means to look at each

part of the command line and be able to extract information into an intelligent format, so that it can be executed by the computer. Since there are variations in how different shells parse a command line, it can be assumed that the shell in question is generic. When a user enters a command line at the prompt, the shell begins by analyzing the command line. The shell will break the command line down into small indivisible pieces called tokens (sometimes they are referred to as atomic).

UNIX Operating SystemWhat is parsing?

Each token is then analyzed in terms of its relationship with the other tokens. This is similar to the way humans exam a sentence. If a noun is present, but no verb, the sentence is deemed incomplete. The shell behaves in much the same manner. It doesn't only check for missing bits, it also makes sure that what is there is in correct order. The shell may have to examine a command line more than once to collect all of the tokens. Each examination is called a pass. The reason for multiple passes is that command lines can be quite complicated, there can be all kinds of substitutions and considerations made before a solid conclusion can be made about the command line data.


What is parsing?On each pass the shell will make a required

substitution and then collect the available tokens. Since the substitutions can be nested (substitutions containing substitutions), the shell may require several passes to collect all of the tokens. As stated above, if at this point in the process the shell determines that the grammar of the command line is incorrect, an error is displayed to the user, or the command is executed. While the actual order in which the tokens are gathered is interesting, it is beyond the scope of this course. Where required (such as aliases) the order of some of the parsing procedure will be presented.


Shell VariablesOne way a shell lets you customize your working

environment is by using shell variables. A shell variable is an item, known by a name, that represents a value of some type. As the term “variable” implies, the value of a shell variable can be changed.

There are two types of shell variables. First, there are variables that act as off/on switches. Second, there are variables that store a particular value as a string of characters.


Shell VariablesUSER or USERNAME contains your current user name.

SHELL holds the path to the current command shell.

PWD is the present working directory. This environment variable is maintained by the system.

HOSTNAME is the current TCP/IP hostname of the computer.


Shell VariablesHOME variable points to your home directory.

MAIL holds the location of the user’s mail spool.

LD-LIBRARY_PATH is a variable to indicate directories in which library files may be found.

TERM holds the name of the current terminal type. EDITOR holds the text editor name you use.


Shell VariablesPATH sets the path for a session, which is a

colon-delimited list of directories in which UNIX-like systems search for executable programs when you type a program name.

PATH=$HOME/bin:/opt/ant/bin:/opt/Lang/jdk1.3.0/j2sdk1_3_0/bin:/usr/local/bin:/bin:/usr/bin:/opt/mysql/bin:/opt/WWW:/opt/Mail:/opt/Lang/Perl/lib:/usr/local/lib:/usr/local/ssl/lib:/usr/local/pvm3/include:/usr/ucb:/opt/sfw/bin:$HOME:.


Why is AWK so important? It is an excellent filter and report writer. Many

UNIX utilities generate rows and columns of information. AWK is an excellent tool for processing these rows and columns, and is easier to use AWK than most conventional programming languages. It can be considered to be a pseudo-C interpreter, as it understands the same arithmetic operators as C. AWK also has string manipulation functions, so it can search for particular strings and modify the output. AWK also has associative arrays, which are incredibly useful, and is a feature most computing languages lack. Associative arrays can make a complex problem a trivial exercise.


AWK - the original from AT&TNAWK - A newer, improved version from AT&TGAWK - The Free Software foundation's version

I suggest you either use NAWK, or GAWK, or convert your AWK script into PERL using the "a2p" conversion program which comes with PERL. PERL is a marvelous language, and I use it all the time, but I do not plan to cover PERL in this class session.


Shell Set CommandDebugging part of a script:set -x # activate debugging # your commands go here...set +x # stop debugging


set -A is Korn Shell (ksh) specific (not available in bash or POSIX SH) and it initializes an array with the specified value(s).

$ set -A COLORS "red" "green" "blue" $ print ${COLORS[0]} red $ print ${COLORS[1]} green $ print ${COLORS[2]} blue


Shell syntax$# - Number of positional parameters (count)$! - Background PID$? - Return value$$ - Process PID$ - Provides the content of a variable ($NUMBER)$0, $1, $2, $3 …$9 - This syntax represents the positional parameters on the command line.

./printnum.sh 4$0 = ./printnum.sh$1 = 4$# = 1


Shell syntax./printnum.sh 3 7 10$0 = ./printnum.sh$1 = 3$2 = 7$3 = 10$# = 3


Shell syntaxA variable is a place holder to the script known

as a parameter. They are represented by a dollar sign ($) followed by a number from 0-9. The $0 variable represents the name of the script, $1 is the first parameter to the script, $2 is the second parameter, and so on.

exit 0 – The return values is a number from 0 to 255. A value of zero (0) indicates a normal exit.exit 1 - Indicates a failure occurred.


“ “ - Double quotes. Removes special meaning of all enclosed characters, except $, `, “, and \.Example: print “The price is $Price.\n”; (interpolation)‘ ’ - Literal quotes. Removes the special meaning of all enclosed characters. A single quote cannot appear within single quotes because a single quote denotes the end of the string.` ` - Single Back-Tic quotes. Used for command substitution. Example: echo The date is `date` (interpolation)LINES=`wc -l $ENTRY | cut -c 1-7`LISTING=`ls -l | cut -f 9`


Example: ./maxlines.sh /bin$0 = ./maxlines.sh$1 = /bin

if [ -d "$1" ]then

action statementfi

#Print the new line countswc –l - Word count with –l (line option).

~ - Tilde (~ means /home/dandrear)


while [ condition]do

action statement(s)done

if [ condition ]then

action statement(s)fi


for name in *do

action statementsdone

Example:while [ "$1" != "" ]

do# Store the value zero (0) in the variable size.

$size = 0done


Example: ./printnum.sh 2 8$0= ./printnum.sh

if [ $# –ne 1 ]then

echo “Please enter a command line argument”

fi


logfile="/var/adm/messages" foreach mon in Sun Mon Tue Wed Thu Fri Sat

do grep $mon $logfile > $logfile.$mon

done

Hands-on-information

Review Lab Assignment 2-1 Simple Shell scripting.Lab assignments should be recorded on cs.franklin.edu (cs.franklin.edu) machine in your “/export/home/$USER/itec400/homework” directory.

Demonstrate how to create a file using the “vi” editor.Execute printnum.sh and maxlines.sh scripts on the

cs.franklin.edu machine.Lab Assignment 2-1 will be complemented with script

logic. Script logic will be utilized to jump start the lab assignment. It contains script logic, 70% percent of the needed coding, and helpful hints to assist your programming skills. In addition to script logic, you will receive a Shell and Perl Commands Quick Reference document in email.

Hands-on-information

Set up course directories (case sensitive)/export/home/dandrearmkdir itec400chmod 705 itec400mkdir homeworkchmod 705 homework

Break Out ProblemsProgram statement (#!/bin/ksh)lessps –ef | wc –lwho | awk ‘{print $1}’ | sort –u | wc –lps –ef | awk ‘{print $1}’ |sort –u | wc –lfind / ex ps –ef | awk ‘{print $9, $1}’Shell language syntax: $#Shell language command: for name in *Shell language command:

NUMBER=$(($NUMBER - 1)) Shell variable: PATH

Upcoming DeadlinesLab Assignment 1-1, Obtain a Proctor for Exams, due January 17, 2016.Lab Assignment 1-2, Install VMware Workstation 8 and Knoppix Virtual Machine, due January 10, 2016.Lab Assignment 1-3, Introduction to Linux, due January 10, 2016.Lab Assignment 2-1, Simple Shell Scripting, due January 24, 2016Lab Assignment 3-1, Advanced Scripting, due January 31, 2016.Read Chapters 1 and 2 in your text book, Essential System Administration.Read Module One listed under the course Web site


Questions?Comments?Concerns?

After each Adobe Connect session, I will remain online to provide assistance or answer questions.

Lab assistance, questions, and chat time

Documents

Agenda