#!/usr/bin/perl -w
                                                                                
# Strict
use strict;
use warnings;
                                                                                
                                                                                
# User-defined
my $total    = 10_000;
                                                                                
                                                                                
#  Main program
my $i;
print "Progress (of whatever)\n";
my $meter = new meter($total);
for (my $i = 0; $i < $total; $i++) {
    $meter->update($i);
    # Call your code here
    &my_subroutine();
}
$meter->update();
print "Done!\n";
                                                                                
                                                                                
#  Subroutines
sub my_subroutine() {
    # For test purposes, sleep for a random interval of milliseconds
    my $nmilli = int(rand(1010) / 1000);
    select(undef, undef, undef, $nmilli);
}
                                                                                
                                                                                
package meter;
                                                                                
# Libraries
use Carp;
                                                                                
                                                                                
#
#   Inputs:  $1 ... the meter object
#            $2 ... total value (when reached, the meter will register 100%)
#
#  Description:  Creates a "visual" meter, which displays an ascii picture
#                representing the progress towards a total count.
#
sub new() {
    my ($proto, $total) = @_;
    ($total || 0) or croak "Invalid 'total' in object 'meter'";
                                                                                
    # User-configurable
    my $width = 64;     # Total meter width
    my $blank = '-';    # Blank symbol
    my $done  = '*';    # Progress symbol
                                                                                
    my $interval = int($total / $width);
    my $class = ref($proto) || $proto;
    my $self = {
        'total'    => $total,
        'interval' => $interval,
        'width'    => $width,
        'blank'    => $blank,
        'done'     => $done,
    };
    bless $self, $class;
    $self->update(0);
    return $self;
}
                                                                                
#
#   Inputs:  $1 ... the meter object
#            $2 ... (optional) the progress count (if undefined, sets the
#                   count to the total, and outputs the final newline).
#
#  Description:  Updates the meter using the given count (which should be
#                a minimum of zero, and a maximum of $this->{'total'}).
#
sub update() {
    my ($this, $count) = @_;
    my $done = defined($count)? 0: 1;
    my $total = $this->{'total'};
    defined($count) or $count = $total;
    return unless ($count == $total || 0 == ($count % $this->{'interval'}));
    my $pct = 100 * $count / $total;
    my $width = $this->{'width'};
    my $size = int($width * $count / $total);
    my $str0 = $this->{'done'}  x $size;
    my $str1 = $this->{'blank'} x ($width - $size);
    select((select(STDERR), $| = 1)[0]);
    printf STDERR " %6.2f%% [%s%s]\r", $pct, $str0, $str1;
    $done and print STDERR "\n";
}
                                                                                
1;