ls | wc -l

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/wait.h>

int main(){

int piped[2];//pipe descriptors
char buf[16 * 1024];
pid_t child;

if(pipe(piped)<0){
   fprintf(stderr,"pipe creation failed \n");
   exit(-1);
 }
 
 if((child = fork()) < 0){
 fprintf(stderr,"process creation failed \n");
 exit(-1);
 }
 
 else if(child == 0){
        close(piped[1]);//close the write end of child
         close(0);//close stdin
         if((dup2(piped[0],0)) < 0){//duplicate read end with stdin;
        fprintf(stderr,"duplication of pipe desc failed \n");
        exit(-1);
        }
        
              int linesrd = read(piped[0],buf,sizeof(buf));
        
        printf("The noof bytes read are %d \n",linesrd);
       
        if(linesrd < 0)
        fprintf(stderr,"Read error \n");
       
        
        buf[strlen(buf)-1] = '\0';
       
       char *buf1 = buf;
      execlp("wc","wc","-l",buf1,NULL); 
        //exit(1);
        }
        
        else{
        
        close(piped[0]);//close read end of pipe
        close(1);//close stdout
        if(dup2(piped[1],1) < 0){//duplicate write end with stdout
        fprintf(stderr," duplication error \n");
        exit(-1);
        }
        
        int w=execlp("ls","ls",NULL);
        
        close(piped[1]);
        
        if(w<0){
        fprintf(stderr,"Something went wrong \n");
        exit(-1);
        }
        
        wait(NULL);
        
        }
        
        return(0);
        }

ameya@ameya-Dell-System-Inspiron-N4110:~/os_concepts$ The noof bytes read are 247 
wc: a.out
basic_shell
Chapter6.pdf
communication
eof.c
fork-wait-exec
l5.pdf
OS_scheduling
pipe
pipe1.c