Update command line output

Question

My program (which happens to be in Perl, though I don\'t think this question is Perl-specific) outputs status messages at one point in the program of the form Progress: x/

Answer 1

Use autoflush with STDOUT:

local $| = 1; # Or use IO::Handle; STDOUT->autoflush;

print 'Progress: ';
my $progressString;
while ...
{
  # remove prev progress
  print "\b" x length($progressString) if defined $progressString;
  # do lots of processing, update $counter
  $progressString = "$counter / $total"; # No more newline
  print $progressString; # Will print, because auto-flush is on
  # end of processing
}
print "\n"; # Don't forget the trailing newline