Simple fork example

This is a very basic example of using fork system call

#include<stdio.h>
#include<unistd.h>
  
int main()
{
    if(fork())
    {
        puts("hello world!!!");
        sleep(5);
    }
    else
    {
        execve("/bin/ls",NULL,NULL);
        puts("error");
    }
    return 1;
}

The program creates a child process and execute 'ls' command , the parent print a message and sleep 5 seconds.