通过用户名找出组名

通过一个用户名找出组名，子程序如下：

sub getUserGroup{
   my ($username) = @_;
   my ($name, $passwd, $uid, $gid)=getpwnam($username);
   my $group = getgrgid($gid);
   return $group;
}

传入用户名：

my $execUsername = getpwuid( $< );
my $group = &getUserGroup($execUsername);