<b_jonas> learn Silent initial consonants in English are: write, wrong, wrist, wrap, wreck, wrest, wrestle, wriggle, wrinkle, wrath, wraith, wreath, wrangle, wren, wright, wrought, wring, writ, writhe, wry; know, knife, knock, knee, knight, knob, knot, knit, knack, knout, knuckle; psychology, psalm, pseudo, psychic, psionics; gnaw, gnash, gnome, gnu, gnat; pneumatic; mnemonic; chthonic; phthisis; bdellium.

#!/bin/bash
[[ "$1" = */* ]] || exit
topic=$(echo "$1" | lowercase | cut -d / -f 1)
[ -z "$topic" ] && exit 1
stuff=$(echo "$1" | cut -d / -f 2-)
perl -i -p -e 's/\n/ /' "wisdom/$topic"
echo "$stuff" >>"wisdom/$topic"
echo -n "Learned '$topic': "
cat "wisdom/$topic"