fork and exec method use together to execute Shell Commands | Operating System

A parent process should create a child process which will execute command "ls -l" using execlp() and will create its child process. The newly created child process should execute system call command "cat hello.txt" and create a child process. The newly created process should execute system call"whoami" and then terminate. Every parent process should wait for terminating its child process.

 

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Create Childs which use System Call Unix Linux Commands C program | Operating System

A parent process should create a child process which will execute system call command "ls"
and will create its child process. The newly created child process should execute system call command "cat" and create a child process. The newly created process should execute system call"whoami" and then terminate. Every parent process should wait for terminating its child process.

Solution :-
Following program demostrate you how to create processes using fork() method and how to  use system call to execute commands on shell terminal. Using simple wait() method parent wait for child execution till partent pause state. just try it out yourself/

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Create Child Using Fork in C program | Operating System

Create a process. Fork to create a child process. Display pid, ppid, gid and uid in
the child process and display pid, gid and uid for the parent process

Solution:
This is small program to create process using fork() method as after call fork() it will return -1 if child creation fail,return 0 if child creation successful ,return child pid to  parent.

#include<stdio.h>
#include<sys/types.h>
#include<unistd.h>

#include<stdlib.h> 

void  main()
{
        pid_t pid;
        pid=fork();
        switch(pid)
        {

           case -1:printf("Child Creation Fail..!!");

                   exit(1); 

           case 0: 

                printf("I AM THE CHILD PROCESS\n");
                printf("The Child process id is %d  ppid is %d gid is %d uid id %d \n",getpid(),getppid(),getgid(),getuid());
               
       
           default:   printf("I AM THE PARENT PROCESS\n");
                printf("The Parent process id is %d gid %d uid %d \n",getpid(),getgid(),getuid());
        }
exit(0);
}

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