#ex_07-5
#Learning Perl Appendix A, Exercise 7.5
while () {
chomp;
($user, $gcos) = (split /:/)[0,4];
($real) = split /,/, $gcos;
($first) = split /\s+/, $real;
$names{$first} .= " $user";
}
foreach (keys %names) {
$this = $names{$_};
if ($this =~ /. /) {
print "$_ is used by:$this\n";
}
}