eg/who

   1 #!/usr/bin/perl
   2 # This assumes your /etc/utmp file looks like ours
   3 open(UTMP,'/etc/utmp');
   4 @mo = (Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec);
   5 while (read(UTMP,$utmp,36)) {
   6     ($line,$name,$host,$time) = unpack('A8A8A16l',$utmp);
   7     if ($name) {
   8         $host = "($host)" if ord($host);
   9         ($sec,$min,$hour,$mday,$mon) = localtime($time);
  10         printf "%-9s%-8s%s %2d %02d:%02d   %s\n",
  11           $name,$line,$mo[$mon],$mday,$hour,$min,$host;
  12     }
  13 }