<Jafet> le/rn double dactyl//Curious spurious verse form, ostensibly catchy to hear but herculean to write. Sadly its bent on the sesquipedalian makes double dactyls pretentious and trite.

[[ "$1" == ?*//* ]] || { echo 'usage: sled file//script'; exit 1; }; key="${1%%//*}"; value="${1#*//}"; [[ -f "$key" ]] || { echo 'Rosebud!'; exit 1; }; sed -i "$value" "$key" ;