$ perl -Mstrict -Mwarnings -le '
    my $wget_url = "/some/path/_SYMBOL__2013 http://example.com/_SYMBOL_.dat";

    my @symbols = qw{A B C};

    for (@symbols) {
        (my $sym_url = $wget_url) =~ s/_SYMBOL_/$_/g;
        print $sym_url;
    }
'
/some/path/A_2013 http://example.com/A.dat
/some/path/B_2013 http://example.com/B.dat
/some/path/C_2013 http://example.com/C.dat