Week Six Agenda Announcements Link of the week Review week four lab assignment This week’s expected outcomes Next lab assignment Review midterm exam Upcoming deadlines Lab assistance, questions and answers

Link of the week This Web site provides useful information how to secure your home computer, things you ought to know, and what should be done to secure a home computer. Science and Technology Resources on the Internet Computer Security This article is written by Jane F. KinKus, who is a Mathematical Sciences Librarian.

Link of the week Define: Trusted System is on that is relied upon to a specific extent to enforce a specific security policy. Define: Trusted Computing means that a computer will consistently behave in specific ways, and those behaviors will be enforced by hardware and software. Where are trusted systems utilized? Homeland security, law enforcement, and social control

Review week five lab assignment kill command Used to send a signal to another process. PID An integer used by the UNIX kernel to uniquely identify a process. PIDs are returned by the fork system call and can be passed to wait() or kill() to perform actions on the given process. When a process is started, it is given the next available PID, and when it terminates, its PID is released for eventual re- use. To determine the PID of any process belonging to you, enter the ps command at the prompt.

Review week five lab assignment

Define make command: The make utility is a software engineering tool for managing and maintaining computer programs. Make provides most help when the program consists of many component files. As the number of files in the program increases so to does the compile time, complexity of compilation command and the likelihood of human error when entering command lines, i.e. typos and missing file names.

Review week five lab assignment Define the makefile: Make goes through the makefile (descriptor) file first starting with the target it is going to create. Make looks at each of the target’s dependencies to see if they are listed as targets. It follows the chain of dependencies until it reaches the end of the chain and then begins backing out executing the commands found in each target's rule. Actually every file in the chain may not need to be compiled. Make looks at the time stamp for each file in the chain and compiles from the point that is required to bring every file in the chain up to date. If any file is missing it is updated if possible.

Review week five lab assignment Makefile Components Comments within a makefile (#) makefile continuation lines (\) Rule tells make both when and how to make a file Dependency Line is a line with a colon (:) test_build.sh contains the make command which calls the makefile. The test_build.sh script is located in the /tmp directory. Demonstrate makefile script under ~varneyg/makelab (cs.franklin.edu)

Review week five lab assignment Key Points About makefile Makefile recompiles all source files for an entire project. Makefile recompiles only those files that have different time stamps. Bottom up control flow. Rules are shell commands.

Review week five lab assignment Other software products that perform similar bundling operations - ANT developed by Apache Jakarta - ANT2 supplied from the Free Software Foundation which is part of Red Hat. What is a dependency between source files? main.cpp  employee.cpp  address.cpp What are the two parts of a dependency rule? 1) What files a file is dependent on 2) Rule that tells how to recompile the file What are the differences between a makefile and a shell script? The rules in a makefile are executed based on dependency, and not sequential order. Scripts execute in sequential order.

Review week five lab assignment Makefile Example The file names used in this example have been abbreviated for simplicity. C++ compilations end in.cpp suffix. The.c suffix extension causes the C compiler to be invoked. The.o suffix represents a object file. The.h suffix represents a header file. The g++ is a compiler, and not a preprocessor. G++ builds object code from your C++ program source. The –c option, compiles source to object code. The –o option, compiles object code.

Review week five lab assignment # The executable file for this project is prog. prog :a.o b.o c.o g++ -o a.o b.o c.o a.o: prog.h a.c g++ –c prog.h a.c b.o:prog.h b.c g++ –c prog.h b.c # The c.c source file is compiled and the object file is c.o. c.o:c.c g++ –c c.c # The c.c is dependent on c.y to be present. c.c:c.y # The rules below are shell commands. g++ -c c.y mv y_table.c c.y

Review week five lab assignment

Key Points About Perl Dynamic typing Dynamic allocation of memory for arrays and hash tables Both procedural and object oriented programming capabilities Rich third party software and use of modules

Review week five lab assignment Regular expression (a.k.a. regex or regexp) Is a pattern that describes a certain amount of text. A basic regular expression could be the single character, e.g.: a Jane is a women. It will match the first occurrence in the string. If succeeding matches are desired, the regex engine must be instructed to do so.

Review week five lab assignment Regular Expression Special Characters Open square bracket [ Backslash\ Caret^ Dollar sign$ Dot. Pipe symbol| Question mark? Asterisk* Plus sign+ Opening and closing round brackets( )

Review week five lab assignment Perl Hash table is an unordered set of scalars, accessed by some string value that is associated with each scalar. %colormap = (“12”, “gray”, “19”, “black”, “30”, “red”); %colormap = (12 => “gray", 19 => “black", 30 => “red"); Define Comma – arrow: The comma-arrow (=>) operator is used to initialize the %members hash variable in the previous slide lines of code. The left side of the comma-arrow operator is expected to be a simple string and therefore it is not necessary to be quoted.

Review week five lab assignment Keys & Values %colormap = (“12”, “gray”, “19”, “black”, “30”, = keys %colormap; # codes array contains just = values %colormap; # colors array contains the colors # Printing things out while (($key, $value) = each(%colormap)) { print $key, “, “, $value, “\n"; } Executing the loop prints: 30, red 19, black 12, grey

Week six expected outcomes Upon successful completion of this module, the student will be able to: Create makefile scripts for software programs. Use pattern rules in make files. Create an effective PowerPoint presentation. Create make files with multiple targets. Install software packages on a server.

Next lab assignment Installing software under UNIX is not always straightforward and easy. System administrators must be familiar with the layout of the file system. During a software installation, the possibility exists that the system could panic and/or have a hard disk failure.

Next lab assignment Installation Software Package Methods Package manager - What are the tasks of a package manager? - The version of UNIX dictates which package manager will be used. - Many Linux versions utilize the Debian Package Manager. Manual - The utilization of makefiles or shell scripts to automate the install as much as possible. - On occasion, the installation of software is done by sending the source code to the site. - What steps are required to install a new software version? - How is a “configure” script utilized?

Next Lab Assignment shell Kernel Hardware Assembler Firmware

Upcoming deadlines Lab Assignment 6-2 (Makefile) is due Feb. 19. Lab Assignment 6-1 (listdir.pl) is due Feb. 26. Midterm exam will be administered from Feb Lab Assignment 8-1, Installation Exercise is due Mar. 4 Midterm outline is available at: Module 4 (Class Website) is for weeks 6,7, and 8. Logic scripts: Makefile_logic (6-2) & listdir_logic.pl (6-1) (copy all files)

Questions and answers Questions Comments Concerns Are there questions regarding the mid-term outline? After class I will help students with their scripts.