build your own shell script

[eefai1129]

i have problems regarding linux shell script. i want to do shell scripting using c programming. my real issues are how to do the i/o redirections using pipe. for example: ls < new.txt

how can i write the code for my shell to execute that command. so far i am stuck with this code:

if(strchr(input,'<') != NULL)
			{
				char *token, *arr1, *arr2, *argv1[10], *argv2[10];
				int i, a, b, n;
				int fds[2];
				int fd;
				
				i=0 , a=0, b=0;
				token = strtok(input,"<");
				arr1 = token;
					
				printf("Arr1 is %s\n", arr1);
						
				token = strtok(NULL,"<");
				arr2 = token; 
						
				printf("Arr2 is %s\n", arr2);
				
				//for(n=0; n < i; n++)
				//	printf("Array1[%d] is %s\nArray2[%d] is %s\n", n,arr1[n],n,arr2[n]);
							
				token = strtok(arr1," \n");
				argv1[a] = token; a++;
					
				while(token!=NULL)
				{
					token = strtok(NULL," \n");
					argv1[a] = token; a++;
				}
				for(n=0; n < a; n++) 
					printf("argv1[%d] = %s\n", n, argv1[n]);
							
				token = strtok(arr2," \n");
				argv2[b] = token; b++;
					
				while(token!=NULL)
				{
					token = strtok(NULL," \n");
					argv2[b] = token; b++;
				}
				for(n=0; n < b; n++) 
					printf("argv2[%d] = %s\n", n, argv2[n]);	
							
					
				pipe(fds);
						
				if(fork() == 0)
				{
					close(fds[1]);
					fd=open(argv2[0],O_RDWR,0600);
					dup2(fd,STDOUT_FILENO);
					dup2(fds[0],STDIN_FILENO);
					close(fds[0]);
					execvp(argv1[0],argv1);
					exit(0);
				}
							
				else
				{
					if(fork() == 0)
					{
						close(fds[0]);
						dup2(fds[1],STDIN_FILENO);
						close(fds[1]);
						execvp(argv2[0],argv2);
						exit(0);
					}
							
					else
					{
						close(fds[0]);
						close(fds[1]);
						wait(NULL);
						wait(NULL);
					}
				}
			}

i appreciate anyone's help. thank you for your answers.