Fork

#include<stdio.h>

#include<unistd.h>

#include<sys/types.h>

#include<sys/wait.h>

#include<stdlib.h>

int main()

{

 int pid;

pid=fork();

 if(pid<0)

 {

printf("\nfork failed\n");

 exit(-1);

 }

 else if(pid==0)

 {

printf("welcome to parent");

execlp("/bin/ls","ls","-1",NULL);

 }

 else

 {

 wait(NULL);

printf("\nchild complete\n");

 exit(0);
   }}