$ cat t.pl
my @files = qw/ a b c d e f g /;
my $total_steps = int @files;
my $step = 0;
for my $file ( @files ){
  $step ++;

  my $t = rand;
  $t *= 3 while $step / $total_steps - .01 > rand;
  print "$t\n";
  sleep $t;

  print "\rStep $step / $total_steps\n";
  select undef, undef, undef, 0.3;
}
print "Done\n";

$ perl t.pl
0.692567903622152
Step 1 / 7
1.5466213811873
Step 2 / 7
1.80846504071083
Step 3 / 7
0.564190293187867
Step 4 / 7
2.93620287911233
Step 5 / 7
0.822297130956301
Step 6 / 7
1.016940946008e+38
^C