As an alternative to parsing the output of the external command you might consider using Sys::Utmp:

use Sys::Utmp;
                                                                      
+          
my $utmp = Sys::Utmp->new();
                                                                      
+          
my %users;
                                                                      
+          
while ( my $utent =  $utmp->getutent() )
{
   if ( $utent->user_process )
   {
      $users{$utent->ut_user}++;
   }
}
                                                                      
+          
$utmp->endutent;
                                                                      
+          
foreach my $user (keys %users)
{
   printf "%s is logged in %d times\n", $user, $users{$user};
}
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/J\