<rdococ> le//rn nvert//To nvert something is to revert it back to its previous form, while recording the reversion as a conversion in itself.

#!/bin/sh
topic=$(echo "$1" | tr A-Z a-z)
[ -e "wisdom/$topic" ] || { echo "$1? ¯\(°_o)/¯"; exit 1; }
cat "wisdom/$topic"