<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.

sep="/"; [[ "$0" == *//* ]] && sep="//"; [[ "$1" == ?*"$sep"* ]] || exit 1; key="$(echo "${1%%$sep*}" | lowercase)"; value="${1#*$sep}"; [ -e "wisdom/$key" ] && verb="Relearned" || verb="Learned"; echo "$value" > "$(echo-p "wisdom/$key")" && echo "$verb «$key»"