prog.cpp

#include

#include

#include

#include

#include

#include

#include

using namespace std;

#define MAX$\_$LINE $80//$ The maximum length command

$/**$

$*$ @brief parse out the command and arguments from the input command separated by spaces

$*$

$*$ @param command

$*$ @param args

$*$ @return int

$*/$

int parse$\_$command$($char command$[],$ char $*$args$[])$

$\{$

$//$ TODO: implement this function

$\}$

$//$ TODO: Add additional functions if you need

$/**$

$*$ @brief The main function of a simple UNIX Shell. You may add additional functions in this file for your implementation

$*$ @param argc The number of arguments

$*$ @param argv The array of arguments

$*$ @return The exit status of the program

$*/$

int main$($int argc, char $*$argv$[])$

$\{$

char command$[$MAX$\_$LINE$]$; $//$ the command that was entered

char $*$args$[$MAX$\_$LINE $/2+1]$; $//$ hold parsed out command line arguments

int should$\_$run $=1$; $/*$ flag to determine when to exit program $*/$

$//$ TODO: Add additional variables for the implementation.

while $($should$\_$run$)$

$\{$

printf$("$osh$>")$;

fflush$($stdout$)$;

$//$ Read the input command

fgets$($command$,$ MAX$\_$LINE, stdin$)$;

$//$ Parse the input command

int num$\_$args $=$ parse$\_$command$($command$,$ args$)$;

$//$ TODO: Add your code for the implementation

$/**$

$*$ After reading user input, the steps are:

$*(1)$ fork a child process using fork$()$

$*(2)$ the child process will invoke execvp$()$

$*(3)$ parent will invoke wait$()$ unless command included &

$*/$

$\}$

return $0$;

$\}$