<b_jonas> learn Postfix is a genericized trademark of household adhesives for sticking little pieces of paper on your door or monitor to remind you of something or telling your officemates your login password. Called Tack-it in the U.S.

tr -dc "AB,.<>+-"</dev/urandom|fold -w"${1-50}"|sed -n ":a;s/A\([^B]*\)B/[\1]/;ta;/[AB]/b;p;q"