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Week Three Agenda. Administrative Issues Link of the Week Review Week Two Information This Week’s Expected Outcomes Next Lab Assignment Break-Out Problems Upcoming Deadlines Lab Assistance, Questions, and Answers. Administrative Issues.

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Week three agenda

Week Three Agenda

Administrative Issues

Link of the Week

Review Week Two Information

This Week’s Expected Outcomes

Next Lab Assignment

Break-Out Problems

Upcoming Deadlines

Lab Assistance, Questions, and Answers

Administrative issues
Administrative Issues

This is the last week for identifying a proctor. Most students have already selected their proctor to administer their midterm exam. By default, the same proctor list will be used for the final exam unless a change request is submitted to the Student Learning Center two weeks prior to the final exam date.

Link of the week
Link of the Week

APA Style writing guidelines will be utilized for all lab assignment reports .

APA Style Sixth Edition


APA Style Writing Workshop


Grading will focus mainly on capitalization, punctuation, grammar, and citation.

Link of the week1
Link of the Week

Linux Forums Web Site

This web site allows individuals to post questions about Fedora Linux and Redhat Linux. The people that maintain this site are knowledgeable users of these operating systems. If your experiencing problems with commands or just want to learn more about these systems, you can find this type of information at this site.


Review week two information
Review Week Two Information


Knoppix software was designed to be used as a Live CD because of specific features that make it’s performance and stability very suitable. It has been noted in several articles that Knoppix works best from a Live CD. Knoppix enthusiasts have attempted to install this software on a hard disk and encountered problems in the process. These problems are most pronounced when installing updates and new software.

Review week two information1
Review Week Two Information

What is the next user interface going to be?

The textual (command line) and the visual (graphical user) interfaces are the two most common modalities used to support engineers in network and system administration positions. The command line interface is recognized as the first generation and the graphical user interface is considered the second generation. Currently, research is trying to determine the next best interface. The command line interface is known as, “under the hood” method of interacting with the operating system.

Review week two information2
Review Week Two Information

CLI Benefits:

Manipulate textual data

Quick customization of data allows engineers the ability to change data to another form

Excellent for filtering data on systems

Commands are rich, expressive, flexible, and powerful

GUI Benefits:

Reduces data overload

Simple filtering and manipulation of the data

Excellent for displaying trends in data

Review week two information3
Review Week Two Information

Users can connect the standard output of one command to standard input of another command by using the pipeline operator (|).


ps -ef

ps –ef | wc –l

ps –ef | awk ‘{print $2}’

ps –ef | grep dandrear

ls –l | cut –c1-3

who | sort > test_file.txt

The output of the who command is piped to the

sort function and written in ascending order in the

test_file.txt file. The “who” and “sort” commands execute in parallel.

Review week two information4
Review Week Two Information


who –b (time of last system boot)

who –d (print dead processes)

who –r (print current run level)

List directory entries using the ls –l | less command

drwxrwxrwx permissions (directory)

-rwxrwxrwx permissions (file)

lrwxrwxrwx permissions (Symbolic link)

-rwxrwxrwx 2 dandrear (Hardlink)

brw-rw---- permissions (block)

crw------- Permissions (character)

Week two information
Week Two Information

A process associates a number with each file that it has opened. 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 (stdin) : Filedescriptor 0 is open for reading.


Standard Output (stdout): File descriptor 1 is open for writing.


Standard Error (stderr): File descriptor 2 is open reading.



ls –a > /tmp/output 2>&1

> is equivalent to 1>

< is equivalent to <0

Review week two information5
Review Week Two Information

A file descriptor is generally an index for an entry in a kernel-resident data structure that contains information on all open files. Each process on the system has its own file descriptor table. A user application passes the abstract key to the kernel through a system call, and the kernel accesses the file for the application.

What is a data structure?

A data structure is a specific way of storing and organizing data in a computer so that it can be accessed with high efficiently. Data structures can be used as a single place for storing unrelated information.

Review week two information6
Review Week Two Information

A data structure is a particular way of storing and organizing data in a computer so that it can be used efficiently.

Different kinds of data structures are suited to different kinds of applications, and some are highly specialized to specific tasks.

Some common data structures:

array, hash table, linked list, queue, and stack

Review week two information7
Review Week Two Information

The grep command searches the named input file(s)for

lines containing a given pattern. Each line found is reported to standard output.


grep UNIX foobar_3

grep ‘^UNIX’ foobar_3

grep ‘UNIX$’ foobar_3

grep pattern foobar_1

grep pattern *

The find command lists all pathnames that are in each of the given directories.


find / -type d –print

find ~dandrear –type d -print

find . –print

find / -name foobar

Review week two information8
Review Week Two Information

Redirection Symbols:

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/Winter_2013_Solutions/test.txt

Append the standard output of a command to a file.

cat foobar_2 >> foobar_1

Review week two information9
Review Week Two Information

One Liner Expressions:

wc –l

wc –l `ls`

wc –l `ls` | sort –bn

wc –l `ls` | sort –bn | tail –n 2

wc –l `ls` | sort –bn | tail –n 2 | head –n 1

Review week two information10
Review Week Two Information

Korn Shell Syntax and Commands

srchfile.sh $1 $2


cd $original

cd $2

listing=`ls –l | cut –c52-80`

for file_name in $listing

do (boundary)

Action Statements (block of statements)

done (boundary)

Review week two information11
Review Week Two Information


ls –l | more

ls –l | less (count the fields/use “q” to quit)

ls -a (does not hide entries)


man (utilizes the less command for reading online documentation).

Review week two information12
Review Week Two Information

Shell Syntax

> test_file

cat /etc/passwd

grep x /etc/passwd | cut –d’:’ –f1

chmod 705 *

chmod 705 test_file

grep line ~dandrear/Summer_2012_Solutions/foobar_1

find ~dandrear –type d -print



Review week two information13
Review Week Two Information


The tilde (~) symbol is used to represent the user’s current home directory

(e.g. /home/dandrear)

Command line arguments example:

./add_all 5 10 8

Command line argument syntax.

$0 = ./add_all, $1 = 5, $2 = 10, and $3 = 8

Review week two information14
Review Week Two Information



umask 077

The umask variable contains the default permissions for a file and a directory.

Variables Used by Korn Shell:

HOME = is set to the full path name of your login directory (/home/dandrear)

Command: echo $HOME

PATH = contains the command search path. It is set to a series of path names separated by colons (:).

Command: echo $PATH

Review week two information15
Review Week Two Information

Variables Used by Korn Shell

SHELL = This entry may be set by the system administrator to the path name of a shell interpreter other than the standard bash.

Command: echo $SHELL

TERM = specifies what terminal you are using.

TMOUT = variable contains the integer attribute. If you set the value greater than zero, ksh terminates if you do not enter a command within the prescribed number of seconds after ksh issues the PS1 prompt.

MAIL = Name of your Mail files

EDITOR = Pathname for your editor

Review week two information16
Review Week Two Information

Manual (man) Page

Man formats and displays the on-line manual pages. If you specify section, man only looks at that section of the manual. Name is normally the name of the manual page, which is typically the name of a command, function, or file. However, if name contains a slash (/) then man interprets it as a file specification.

Each section has an introduction which can be obtained with, e.g., "man 2 intro“ or “man ./foobar_1”.

If MANPATH is set, man uses it as the path to search for manual page files.

Review week two information17
Review Week Two Information



Man Page Sections

1 Commands

2 System calls

3 C library routines

4 Devices and networks

5 File formats

6 Games and demos

7 Miscellaneous

8 System administration.

Review week two information18
Review Week Two Information

Types of File and Directory Access:

AccessFile MeaningDirectory Meaning

r View file contents Search directory contents

w Alter file contents Alter directory contents

x Run executable file Make your current directory

-rwx------ Owner (columns 2-4) 700 (111000000)

----rwx--- Group (columns 5-7) 070 (000111000)

-------rwx Other (columns 8-10) 007 (000000111)

Review week two information19
Review Week Two Information

Shell and Programs Access:

To run a shell script, you will need read (r) and execute (x) access (r-x). The read access mode is a binary 4. The execute access mode is a binary 1.

To run a binary executable program, you will need execute (x) access (--x). The execute access mode is a binary 1.

Week s 2 3 expected outcomes
Week’s 2 & 3 Expected Outcomes

Upon successful completion of this module, the student will be able to:

  • Create scripts using shell/Perl variables and program control flow.

  • Use redirection and pipes to combine scripts and executables.

  • Use man page system and find script tools.

  • Discuss Perl Language

Next lab assignment
Next Lab Assignment

Introduction to Perl:

Perl - Practical Extraction and Report Language

Originally developed by Larry Wall, a linguist.

Perl is 21 years old and Perl 5 is 14 years old.

  • Perl is a simple language

    - Compiles and executes like a shell script or a batch file

    - Perl doesn’t impose special growth limitations on arrays and data strings

    - Perl is a composite of C, AWK, and Basic

    - Originally developed to process text and automating tasks.

Next lab assignment1
Next Lab Assignment

Introduction to Perl:

The AWK utility is an interpreted programming language typically used as a data extraction and reporting tool. It is a standard feature of most Unix-like operating systems.

AWK was created at Bell Labs in the 1970s, and its name is derived from the family names of its authors – Alfred Aho, Peter Weinberger, and Brian Kernighan.

The power, terseness, and limits of early AWK programs inspired Larry Wall to write Perl just as a new, more powerful POSIX AWK and gawk (GNU AWK) were being defined.

Next lab assignment2
Next Lab Assignment

Perl’s range of flexibility

- System administration

- Web development

- Network programming

- GUI development

Major features

- Procedural Programming

Sequence or unstructured statements

Includes routines, subroutines, methods, or functions

- Object Oriented Programming

Module uses “objects” and their interactions to design applications and computer programs.

Next lab assignment3
Next Lab Assignment

Major features (continued)

- Powerful built-in support for text


- Large collection of third-party


Next lab assignment4
Next Lab Assignment

  • Why is awk language so important?

    Awk language is an excellent filter and report writer. Many UNIX utilities generate rows and columns of information. Awk is an excellent tool for processing rows and columns, and it is easier to use awk than other conventional programming languages. Perl recognized the importance of awk, so it was included and enhanced in Perl.

Next lab assignment5
Next Lab Assignment

The Advanced Scripting lab assignment requires two shell scripts to be written.




Execution of srch.sh and srchfile.sh

Case #1: ./srch.sh <pattern> <file name / directory name>

Case #2: ./srch.sh <pattern> <.>

The srch.sh script will call the srchfile.sh script to perform a specific task. The srchfile.sh searches for a file with a pattern and outputs the matching information to standard output. After all directory entries have been read, control is returned to the main script, srch.sh.

Break out problems
Break Out Problems

1. scalar@ARGV

2. $ARGV[0]

3. filter

4. unless


6. exit 1

7. $ARGV[1]

8. % (%directory)

9. $ ($quote)

10. @ (@names)

11. Regular expressions

12. tr [a-z] [A-Z] < foobar > /tmp/foo

Next lab assignment6
Next Lab Assignment

Read your Programming Perl text book.

Chapter One (1)

Chapter Two (2)

Review Chapter 32: Standard Modules

Review Chapter 33: Diagnostic Output Messages

Read Module Two listed under the course web page.

Upcoming deadlines
Upcoming Deadlines

  • Lab Assignment 3-1, Advanced Scripting, due February 3, 2013.

  • Lab Assignment 4-1, Simple Perl Exercise, due February 10, 2013.

Lab assistance questions and answers
Lab Assistance, Questions and Answers




After class I will help students with their scripts.