<b_jonas> slashlearn block device/Block devices are a concession made in Unix to make raw hard disks and magnetic tape have a similar interface to regular files and terminals. Since magnetic tapes can\'t write individual bytes, only entire blocks, the interface isn\'t exactly the same, thus the dreaded dd obs= option was born.

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