Some interesting functions
exists, defined: print “Exists\n” if exists $hash{$key};print “Defined\n” if defined $hash{$key};
join:$_ = join ’:’, $login, $passwd, $uid, $gid;
map, split:@words = map {split ’ ’} @lines;
pop, shift, push, unshift;@list = push (@list, pop @list);
reverse:@rlist = reverse @list;