Week Three Agenda Administrative Issues Link of the week Review week two lab assignment This week’s expected outcomes Next lab assignment Upcoming deadlines Lab assistance, questions, and answers

Administrative Issues Lab assignments such as LDAP, Reiser File System, and open source papers shall follow APA documentation style. APA Style APA Style Writing Workshop learning-center/academic-support/workshops.html Grading will focus on capitalization, punctuation, and citation.

Administrative Issues This will be the last request for Proctor Information. Many students have already created and submitted their Proctor Information. The information will be used for both the mid-term and final exam, unless the student submits another Proctor Information request.

Link of the week This is a Knoppix Web site, receive a free and Open Source Live Linux CD. Knoppix is a GNU/Linux distribution that boots and runs completely from CD. It includes Linux software and desktop environments, with programs like OpenOffice.org, The Gimp, Apache, PHP, MySQL and many more open software programs.

Link of the week Known as the “Unix Millennium bug” – When you use the date command in Unix, it computes the date as the number of seconds from January 1, Unix stores that information as a “signed 32-bit integer”. Well, that’s a really big number that will “flip over” and become negative on Tuesday, January At around 3am that morning, some Unix systems will think it is December at around 8:45pm

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 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 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 varneyg ls –l | cut –c1-3 who | sort > /tmp/test_file.txt The output of the who command is piped to the sort function and written in ascending order in the /tmp/test_file.txt file. The “who” and “sort” commands execute in parallel.

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) brw-rw---- permissions (block) crw Permissions (characterr)

Review week three lab assignment 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. Data structures can be used as a single place for storing unrelated information.

Review Week Two Information Definition data structure 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 three 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 < ~varneyg/test.file Append the standard output of a command to a file. cat file1 >> file2 “Bit Bucket” – echo “stuff” >/dev/null

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 file_3 grep ‘^UNIX’ file_3 grep ‘UNIX$’ file_3 grep pattern file_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 file_3

Review Week 2 assignment Logic Scripts: Lab 2-1: printnum_logic.sh & maxlines_log2.sh Lab 3-1: srchfile_logic.sh & srsh_logic.sh NOTE: “…” are areas you need to modify (not tied to # of characters (Xs are indicative of the # of characters needed – currently only in maxlines_logic2.sh)

Review week three 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 The srch.sh script will call the srchfile.sh script to perform a specific task. That specific task is task to search a file for a pattern and report it to standard output. When the end of file is reached, control is then returned to the main script, srch.sh.

Review week three lab assignment Shell syntax srchfile.sh $1 $2 original=$PWD cd $original cd $2 listing=`ls –1`(-1 is a number) for file_name in listing do Action Statements done

Review week three lab assignment ls –l | more ls -a (does not hide entries) 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) (< not necessary – can just use cat test_file) cat foobar_2 >> foobar_1 (append first file to second file) 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 three lab assignment Demonstrate /export/home/varneyg/.profile umask 077 Specifies the default permissions for a file and directory Demonstrate The command line arguments are: $0 $1 $2 $3 …./arg_list.sh FIRST_ARG SECOND_ARG

Review week three lab assignment HOME = is set to the full path name of your login directory (/export/home/varneyg) 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 PWD = Current or Present Working Directory

Review Week Two Information Types of File and Directory Access: AccessFile MeaningDirectory Meaning rView file contentsSearch directory contents wAlter file contentsAlter directory contents xRun executable fileMake your current directory -rwx Owner rwx--- Group rwxOther 007

Review Week Two Information Shell and Programs Access: To run a shell script, you will need read (r) and execute (x) access. To run a binary executable program, you will need execute (x) access.

Review week three lab assignment > test_file cat /etc/passwd grep x /etc/passwd | cut –d’:’ –f1 chmod 705 * chmod 705 test_file grep lines ~varneyg/testlines find ~varneyg –type d -print $0

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 Introduction to Perl Perl - Practical Extraction and Report Language 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 manipulate 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 Perl Lab Assignment Major features (continued) - Powerful built-in support for text processing - Large collection of third-party modules. -Can even download and run on Windows:

Next lab assignment Read the text, Programming Perl Chapter One (1) Chapter Two (2) Chapter 32: Standard Modules Chapter 33: Diagnostic Output Messages

Next Perl Lab Assignment Online Reading Sections Chapter One: (under Overview – Natural and Artificial Languages) Variable Syntax Singularities Pluralities Arrays, Hashes, Complexities Chapter Two: (Under The Gory Details – Bits and Pieces) Variables, Names, Name Lookups, Scalar Values Numeric Literals Pick Your Own Quotes or Leave The Quotes Out Entirely Interpolating Array Values

Next Perl Lab Assignment Online Reading Sections Chapter Three: (under “The Gory Details – Unary & Binary Operators) Multiplicative Operators, Additive Operators Shift Operators Named Unary and File Test Operators Relational Operators, Equality Operators Bitwise Operators

Upcoming Deadlines Obtain Proctor (1-1) due on Jan. 30. Lab Assignment 2-1 due on Jan. 22. Lab Assignment 3-1 due on Jan. 29. Lab Assignment 4-1 due on Feb. 5. Read Chapters 1 and 2 in Programming Perl text. Review Chapter 32: Standard Modules Review Chapter 33: Diagnostic Output Messages Read Module Two listed under the course Web site.

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