-n   causes Perl to assume the following loop around your
            program, which makes it iterate over filename argu-
            ments somewhat like sed -n or awk:

              LINE:
                while (<>) {
                    ...             # your program goes here
                }

##</code><code>##

while(<>){
  / /, $;{$`}++}{print $_, $/ ^= "*" for %
}

##</code><code>##

while(<>){
  / /, $;{$`}++
}
{
  print $_, $/ ^= "*" for %
}

##</code><code>##

while(<>){
  / /, $;{$`}++
}
{
  print $_, $/ ^= "*" for %;
}

##</code><code>##

use English;

while( <ARGV> ){
  m/\s/;
  $hash{$PREMATCH}++;
}
{
  for( %hash ){
    print $_, $INPUT_RECORD_SEPARATOR ^= '*';
  }
}

##</code><code>##

$username $num_logins
$username $num_logins

##</code><code>##

$ who|perl -MO=Deparse -ne'/ /,$;{$`}++}{print$_,$/^="*"for%'
LINE: while (defined($_ = <ARGV>)) {
    / /, ++$;{$`};
}
{
    foreach $_ (%;) {
        print $_, $/ ^= '*';
    }
}

##</code><code>##

s**lil*;  $*=join'',sort split q**;  s;.*;grr; &&s+(.(.)).+$2$1+; $; =
qq-$_-;s,.*,ahc,;$,.=chop for split q,,,reverse;print for($,,$;,$*,$/)