or download this
$ perl -e'$g="a"; print $g++, " " while $g ne 'cw'; print "\n"'
a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af
+ag ah ai aj ak al am an ao ap aq ar as at au av aw ax ay az ba bb bc
+bd be bf bg bh bi bj bk bl bm bn bo bp bq br bs bt bu bv bw bx by bz
+ca cb cc cd ce cf cg ch ci cj ck cl cm cn co cp cq cr cs ct cu cv