An example:

my @people = qw/jerry kramer george elaine/;

sub sortnames {
    my( @names ) = @_;
    @names = sort @names;
    return wantarray ? @names : join ' ', @names;
}

my $sorted_string = sortnames( @people );

my @sorted_list = sortnames( @people );

print $sorted_string, "\n";

print "$_\n" foreach @sorted_list;
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The idea is that if the function is evaluated in list context, it returns one thing, and if evaluated in scalar context, it returns something else. In this case, you either get a sorted list of names, or you get a single string containing the sorted names. Another classic example of "wantarray" type functionality at work is the built-in localtime function, where in list context you get a list containing year, day, month, and so on, while in scalar context you get a stringified time/date stamp. I hope this helps...