Operating Systems and Security - Report Example

Topic: Operating systems and security Pre-brief 26th February Shell Program 1. Introduction The command interpreter, Shell, provides UNIX users with an interface to the kernel. This Command Line interpreter (CLI) interprets the commands a user types in and tries to arrange them in order of how they will be executed. It also allows for the users to code an interpretive script and group these together using simple programming constructs such as ‘while’, ‘if’, while and ‘for’. A shell script is written to and executed as a single command. This piece of work will dwell on writing a simple menu driven scenario. Information that the program will show include List of users who are logged in Present handling directory Show the content of ‘etc’ directory. 1.2. Source code /* Ali Baba, SID: 000001, ....SE CW1, BSc etc. */ !/bin/bash # # A menu driven Shell script which has following options # List of all Processes running on your Linux machine # List of users currently logged # Present handling directory # List disk space/ System Health # Show Content of /etc directory # Backup current Directory files # List content of files backed up!! # Exit # As per option do the job # -------------------------------------------------------------- # Student ID: # Name: # Course: # -------------------------------------------------------------- while : do clear echo " M A I N - M E N U" echo "1. List of all Processes running on your machine" echo "2. List of users currently logged" echo "3. Present handling directory" echo "4. List disk space/ System Health" echo "5. Show Content of /var/lib directory" echo "6. Backup current Directory files" echo "7. List content of files backed up!!" echo "8. Exit" echo -n "Please select option between [1 - 8] then press [enter] Key:" read opt case $opt in 1) echo "************ List of all Processes running *************"; ps aux | less;; 2) echo "*********** List of users currently logged"; who | more /etc/passwd;; 3) echo "You are in $(pwd) directory"; echo "Press [enter] key to continue. . ."; read enterKey;; 4) echo "*********************Checking Disk space*****************"; df -h; echo "Press [enter] key to continue. . ."; read enterKey;; 5) echo "*********************Show Content of /var/lib*****************"; ls -all /var/lib; echo "Press [enter] key to continue. . ."; read enterKey;; 6) echo "*********************Backing up current directory files*****************"; rm -rf /home/user/Desktop/bakup; mkdir /home/user/Desktop/bakup; cp -rf $2 $(pwd)/home/user/Documents/ /home/user/Desktop/bakup; echo "File has been backup on $(pwd)/backup" echo " Press [enter] key to continue. . ."; read enterKey;; 7) echo "************ Content of files backed up *************"; ls -altr /home/user/Desktop/bakup/; echo "Press [enter] key to continue. . ."; read enterKey;; 8) echo "Bye $USER"; exit 1;; *) echo "$opt is an invaild option. Please select option between 1-8 only"; echo "Press [enter] key to continue. . ."; read enterKey;; esac done      Output Screenshots: Figure 1: Main Menu: list the options available from 1 -8 Figure 2: List of processes running on the machine Figure 3: Users logged on: user tty1 & pts/0 logged on and time of logging Figure 4: Present handling directory: /home/user/Desktop Figure 5:Disk space and system health Figure 6: Content of the /var/lib/ directory Figure 7: List content of files backed up Figure 8: Exit the shell script 1.3. Conclusion I have in this exercise being able to write a simple shell script for checking the users who are logged in, system health and the disk space. The program can also, through an option which the author select from 1-8 able to display the content of the ‘var/lib’ directory. Part Two: a C program 2.1. Introduction C is programming language which is a high level language in implemented in UNIX OS. A source code is written which is then followed by a compilation process where the compiler translates it into an object code. Object code entails a code language of machine instructions which the computer can execute. 2.2. Source Code /* Ali Baba, SID: 000001, ....SE CW1, BSc etc. */ #include #include #include main() { char string[100], ch; int s = 0, count[26] = {0}; printf("Enter a string\n"); gets(string); if(string[s]>=48 && string[s]=65 && string[s]= a && string[s] =A && string[x]=a && string[x] Read More