This is my super-simple progress indicator, called dots. I wrote it at least 12 years ago when I was on a slow terminal and wanted to know unpacking a tarball was still progressing (the verbose output would have taken too much bandwidth!). Now I copy it onto every new system I use.

It prints one period (.) for every 1000 lines of text piped into it. It just shows that there is still activity, not progress, but often this is enough.

A typical usage is:

  tar xvfz some_huge_tarball.tar.gz | dots

It defaults to one dot per 1000 lines, but the first argument can be a number to specify another interval.

  #!/usr/bin/perl

  $| = 1;
  $i = 0;

  if ($#ARGV < 0) {
    $number = 1000;
  } else {
    $number = shift(@ARGV);
  }

  while (<STDIN>) {
    print '.' unless ($i % $number);
    $i++;
  }

  print "\n";