For interactive text programs, creates a spinning bar to let the user know the program is still working away. Sample use while slowly processing through a file: 
$| = 1; # autoflush required
while (<$fh>) {
   spinner if !($. % 100);
   # process line
}

[download]
{
    my @spin = qw(- \\ | /);
    my $time = time;
    sub spinner {
        if ($time != time) {
            ++$time;
            my $spin = shift @spin;
            print STDOUT "\r$spin";
            push @spin, $spin;
        }
    }
}

[download]

In reply to spinner to keep the patiently waiting user patient by ysth

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