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

my %hash = (one=>1, two=>2, three=>3, four=>4, five=>5);
my $flag; # prevent infinite loop
while ( my ($key, $val) = each %hash ) {
    if ( $val == 4 && ! $flag ) {
        my @keys = keys %hash;
        print "\t$_\n" for @keys;
        $flag = 1;
    }
    print "$key : $val\n";
}