#ex_14-2
#Learning Perl, Appendix A, Exercise 14.2
open(PW,"/etc/passwd");
while (<PW>) {
  chop;
  ($user,$pw,$uid,$gid,$gcos) = split(/:/);
  ($real) = split(/,/, $gcos);
  $real{$user} = $real;
}
close(PW);

open(WHO,"who|") || die "cannot open who pipe";
while (<WHO>) {
  ($login, $rest) = /^(\S+)\s+(.*)/;
  $login = $real{$login} if $real{$login};
  printf "%-30s %s\n",$login,$rest;
}