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 Upcoming Deadlines Lab assistance, questions and chat time

Announcements Class participation Class participation is an essential element in all course work. Many times a student’s final grade borderlines the next highest grade (.5 – 1). It is the instructors discretion based on the students participation in class, as to whether the next highest grade is given. Convince me professionally, that you want an “A” in this course.

Link of the week The above WEB site lists most all operating systems cool site with posters/toolshttp:// Definition of Operating System (OS) Common operating systems are: UNIX, Linux, HP-UX Basic tasks performed by an operating system –Control and allocate memory –Prioritize system requests –Control input and output devices –Facilitate networking and management file systems

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

Use of the Virtual Machine Knoppix features Demonstrate how to ftp a file from Knoppix software to the cs.franklin.edu (Einstein) machine using VMware software Open two Konqueror windows Enter the ftp protocol – in one window Open a Konsole screen and create a file to transfer to the cs.franklin.edu machine.

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)

Review week one lab assignment less command q (terminates pagination) Enter or Return key (advance one line) Space bar (refresh full screen) Location of weekly Power Point presentations: File format: Week_2.ppt

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

Review week one lab assignment Reserved words The following reserved words for the Bourne shell are recognized only when they appear without quotation marks as the first word of a command. for esacfiwhile do ifelifcase done thenelse{ } ( )

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

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

Review week one lab assignment grep find ls ls –a mkdir cd $1 $1, $2, $3 cat chmod mv

Review week one lab assignment sleep diff cd sort umask who who am i

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.

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 used to communicate with UNIX. One of the things that makes the UNIX 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, that perform specific tasks. A program that provides easy access to these utilities by the user is called a shell.

Next lab assignment A shell enables the user to interact with resources of the computer, such as programs, files, directories, and devices. An interactive shell acts as a command interpreter. In its role as a command interpreter, the shell is the interface between the user and the system. The user enters text commands to the shell, and the shell carries them out, usually by running programs.

Next lab assignment Most shells can also be used as a programming language. Users can combine command sequences to create new programs. These programs are known as shell scripts. Shell scripts automate 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

Next lab assignment Concentric Circle Relationship

Next lab assignment exit Each 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.

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

Next lab assignment 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: File descriptor 0 is open for reading. Standard output: File descriptor 1 is open for writing. Standard error: File descriptor 2 is open reading. /dev/null – redirect output here if you don’t care about it (a.k.a – “bit bucket”)

Next lab assignment 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

Next lab assignment 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 ~varneyg/itec400/testfile grep pattern test_1 grep pattern * The find command lists all pathnames that are in each of the given directories. Demonstrate: find / -type d –print find ~varneyg –type d -print find. –print find / -name foobar

Next lab assignment 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 < ~/test.txt Append the standard output of a command to a file. cat foobar_2 >> foobar_1

Review week one lab assignment #!/bin/ksh if [ $# -ne 1 ] # Verify that there is one command line argument. then Action statements exit elif [ $1 -le syntax ] # Verify that the argument value is greater than zero then Action statements exit fi while [ $variable -gt 0 ] # Argument value must be greater than zero. do printf $variable if [ $variable -gt 1 ] # If the value doesn’t equal one, output a comma then Action statements fi VARIABLE=$(( $VARIABLE - 1)) done print

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 DIR="."

Review week one lab assignment # Case #2 and 3. # The number of arguments on the command line equals one. if [[ $X -eq 1 ]] then # Is the directory entry a directory? if [[ -X $1 ]] then # Assign the command line argument to the variable, DIR="$X" else printf "$ERRORX" exit 1 fi

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

Review week one lab assignment Current directory (maxlines.sh Case #1) /~varneyg/itec400/homework printnum.sh maxlines.sh Different directory (maxlines.sh Case #2) /bin

Next lab assignment The 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, …).

Upcoming Deadlines Simple Shell scripts, Lab Assignment 2-1 due Jan. 22. Advanced Scripting, Lab Assignment 3-1 due Jan. 29. Provide your proctor information for Lab Assignment 1-1 by Jan. 30. Verify that your login is correct on Einstein. Configure your directory structure on Einstein to comply with course specifications.

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