Week Three Agenda Link of the Week Review Week Two Information 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 This is the last week for identifying a proctor. Many students have already selected their proctor for their midterm. This same proctor list will be utilized for the final exam unless a change request is emailed to me two weeks prior to the exam date.

Link of the Week APA Style writing guidelines will be utilized for all lab assignment reports . APA Style http://www.apastyle.org/learn/ APA Style Writing Workshop http://www.franklin.edu/student-services/student-learning-center/academic-support/workshops.html Grading will focus on capitalization, punctuation, grammar, and citation.

Link of the Week Linux Forums Web Site This site allows users to post questions about Fedora Linux and Redhat Linux. The people that maintain the site are knowledgeable users. You can find information about commands that don’t work. http://www.linuxforums.org/forum/redhat-fedora-linux-help/73994-system-commands-not-working-unless-sbin.html

Review Week Two Information Caveat: 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 Information 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 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.

Review Week Two Information Commands 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)

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) : File descriptor 0 is open for reading. /dev/stdin Standard Output (stdout): File descriptor 1 is open for writing. /dev/stdout Standard Error (stderr): File descriptor 2 is open reading. /dev/stderr Demonstrate ls –a > /tmp/output 2>&1 > is equivalent to 1> < is equivalent to <0

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. A data structure is a specific way of storing and organizing data in a computer so that it can be accessed with high efficiently.

Review Week Two Information

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. Demonstrate: 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 Information Redirection 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/Fall09_Solutions/test.txt Append the standard output of a command to a file. cat foobar_2 >> foobar_1

Review Week Two Information Shell Syntax and Commands srchfile.sh $1 $2 original=$PWD cd $original cd $2 listing=`ls –l | cut –c57-80` for file_name in listing do Action Statements done

Review Week Two Information Commands ls –l | more ls –l | less (count the fields/use “q” to quit) ls -a (does not hide entries) less man (utilizes the less command for reading online documentation). cat > test_file (keyboard input goes into test_file) cat < test_file (test_file is displayed on terminal) cat foobar_2 >> foobar_1 (append first file to second file)

Review Week Two Information Commands > test_file cat /etc/passwd grep x /etc/passwd | cut –d’:’ –f1 chmod 705 * chmod 705 test_file grep line ~dandrear/Fall09_Solutions/foobar_1 find ~dandrear –type d -print myArray[1]=$1 $0

Review Week Two Information Demonstrate /export/home/dandrear/.profile umask 077 The umask variable contains the default permissions for a file and a directory. What does the ~ provide? The command line arguments are: $0 $1 $2 $3 …

Review Week Two Information Variables Used by ksh HOME = is set to the full path name of your login directory (/export/home/dandrear) PATH = contains the command search path. It is set to a series of path names separated by colons (:). SHELL = This entry may be set by the system administrator to the path name of a shell interpreter other than the standard bash. 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

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 Man page Man formats and displays the on-line manual pages. If you specify section, man only looks in 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.

Next Lab Assignment Section 1 covers commands, 2system calls, 3 C library routines, 4 devices and networks, 5 file formats, 6 games and demos, 7 miscellaneous, 8 system administration. 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.

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 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 Assignment Major features (continued) - Powerful built-in support for text processing - Large collection of third-party modules.

Next Lab Assignment The Advanced Scripting lab assignment requires two shell scripts to be written. srch.sh srchfile.sh Demonstrate Execution of srch.sh and srchfile.sh Case #1: ./srch.sh <pattern> <file name / directory name> 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 1. scalar@ARGV 2. $ARGV[0] 3. exit 0 4. unless 5. $NUMBER 6. exit 1 7. $ARGV[1] 8. % (%directory) 9. $ ($quote) 10. @ (@names) 11. diff 12. tr “[a-z]” “[A-Z]” < filein > fileout

Next Lab Assignment Read your Programming Perl text. Chapter One (1) Chapter Two (2) Review Chapter 32: Standard Modules Review Chapter 33: Diagnostic Output Messages

Upcoming Deadlines Lab Assignment 3-1 is due on October 4, 2009. Mid-term exam will be administered from October 19 through 24. Midterm outline will be posted on the Bulletin Board by October 4, 2009.

Lab Assistance, Questions and Answers Comments Concerns After class I will help students with their scripts.