The Shell or Command Line Interpreter is the fundamental Use

The Shell or Command Line Interpreter is the fundamental User interface to an Operating System. Your third project is to write a simple shell - myshell - that has the following properties: The shell must support the following internal commands: a. clr - Clear the screen. b. dir - List the contents of directory . c. environ - List all the environment strings. d. run prog p1 p2 ... exec\'s to prog passing I the parameters p1 p2... e. quit - Quit the shell. All other command line input is interpreted as program invocation, which should be done by the UNIX system() function The command line prompt must contain your UNIX username. Example: wp663000>> Project Requirements Design a simple command line shell that satisfies the above criteria and implement it on the alpha.fdu.edu UNIX platform. The source code MUST be extensively commented and appropriately structured to allow your peers to understand and easily maintain the code. Properly commented and laid out code is much easier to interpret, and it is in your interests to ensure that the person marking your project is able to understand your coding without having to perform mental gymnastics! The submission should contain only 1 source code file. The person marking your project will be building your shell program from the source code provided. If the submitted code does not compile it cannot be marked!

Solution

question is not clear..just please post understend way..not clear

To use the pulse accumulator connect an input to Port T7 The pulse accumulator operates in two modes: 1. Event-Count Mode 2. Gated Time Accumulation Mode In Event-Count Mode, the pulse accumulator counts the number of rising or falling edges on Port T7 – You can set up the pulse accumulator to select which edge to count – The counts are held in the 16-bit PACNT register – On each selected edge the PAIF flag of the PAFLG register is set – When PACNT overflows from 0xFFFF to 0x0000, the PAOVF flag of the PAFLG register is set In Gated Time Accumulation Mode the pulse accumulator counts clock cycles while in the input to Port T7 is high o