CS-3013 & CS-502 Operating Systems Summer 2006 Programming Project #1 CS-3013 & CS-502 Operating Systems Summer 2006 CS 3013 & CS 502 – Summer 2006 Programming Project #1

Programming Assignment Write a command called doit to execute another command and print out statistics Extend doit to become a basic shell that prompts for and executes commands Extend your shell to shell2 to execute commands in the background CS 3013 & CS 502 – Summer 2006 Programming Project #1

Purpose To practice using the fork and exec facilities of Unix/Linux To learn how to find and use on-line documentation about system calls and system facilities. man pages To be accustomed to speaking directly with the operating system CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 1: doit doit command:– Must execute on a CCC or CS Linux system Take another command line as argument Execute that command Print out statistics about command Must execute on a CCC or CS Linux system May not use system() system call Helpful hints:– fork(), execve(), wait() getrusage(), gettimeofday() CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 1 (output) % doit cat /etc/motd < print the current message of the day > < statistics about the cat command > CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 2: shell Repeatedly prompt for command lines Execute each command and print out statistics, as in doit Implement special “built-in” commands exit cd dir Special conditions Exit on end of file Complain about illegal commands Check for line length, number of arguments CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 2 output % shell ==>cat /etc/motd < print the current message of the day > < statistics about the cat command > ==>cd dir < current directory is changed to dir > ==>ls < listing of files in current directory > < statistics about this ls command > ==>exit % < back to the Unix prompt > CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 3: Background execution (shell2) Modify shell to support execute commands in background, indicated by ‘&’ character Causes shell to prompt for next command before previous command is complete jobs built-in command lists background tasks in progress Report completion at next opportunity CS 3013 & CS 502 – Summer 2006 Programming Project #1

Part 3 output % shell2 ==>numbercrunch & [1] 12345 < indicate background task #1, process id > ==>jobs [1] 12345 numbercrunch < print process id and command name for tasks > ==>ls < listing of files in the current directory > < statistics about this ls command > ==>cat /etc/motd [1] 12345 Completed < indicate background job done > < statistics about numbercrunch command > < print the current message of the day > < statistics about this cat command > ==>exit % < back to Unix prompt > CS 3013 & CS 502 – Summer 2006 Programming Project #1

Project submission Due Monday, June 1 at start of class Submit via turnin command = ‘/cs/bin/turnin’ on CCC machines classname = ‘cs502’ assignment = ‘project1’ Bring copy of code, test case, and printout to class. Put your name on all files! CS 3013 & CS 502 – Summer 2006 Programming Project #1

Term Project Assignment CS 3013 & CS 502 – Summer 2006 Programming Project #1