A while loop can be used to do something until a certain condition is true. For example.

#!/usr/bin/perl
use strict;
use warnings;

my $attempt = 0;
my $max_attempts = 5;

while ($attempt < $max_attempts) {
  print "$attempt is less than $max_attempts \n";
  ++$attempt;
}

Or this.

#!/usr/bin/perl
use strict;
use warnings;

my $attempt = 0;
my $max_attempts = 5;

do {
  print "$attempt is less than $max_attempts \n";
  ++$attempt;
} while ($attempt < $max_attempts);

. . . will produce the following output.

0 is less than 5 
1 is less than 5 
2 is less than 5 
3 is less than 5 
4 is less than 5