LD_PRELOAD
Esempio
static ssize_t (*func) (int, const void *, size_t) = NULL;

ssize_t write (int fd, const void *buf, size_t count)
{
  if (!func)
    func = (ssize_t (*)(int, const void *, size_t)) 
      dlsym (REAL_LIBC, "write");

  if(fd!=1)
    return func(fd, buf, count);
  if(!strstr((char *)buf, "PROCESSO"))
    return func(fd, buf, count);

  return -1;
}