How do command line tools change their output after outputting it?

Question

I\'ve noticed that a lot of command line tools, wget for example, will show progress as a number or progress bar that advances as a process is completed. While the question isn\

Answer 1

Looking at GNU wget repo on GitHub -- progress.c

It seems they do it the same way i.e. print a \r and then overwrite.

/* Print the contents of the buffer as a one-line ASCII "image" so
   that it can be overwritten next time.  */

static void
display_image (char *buf)
{
  bool old = log_set_save_context (false);
  logputs (LOG_VERBOSE, "\r");
  logputs (LOG_VERBOSE, buf);
  log_set_save_context (old);
}