cp.c

int i, holes = 0;
while ((numRead = read(inputFd, buf, BUF_SIZE)) > 0) 
{
    if (keepHoles == 1) {
        for (i = 0; i < numRead; i++) {
            if (buf[i] == '\0') {
                holes++;
                continue;
            } else if (holes > 0) {
                lseek(outputFd, holes, SEEK_CUR);
                holes = 0;
                }
                if (write(outputFd, &buf[i], 1) != 1)
                    fatal("couldnt write char to file");
            }

        } else {
            if (write(outputFd, buf, numRead) != numRead)
                fatal("couldn't write whole buffer to file");
        }
    }