<wib_jonas> slashlearn hand injuries//Hand injuries are surprisingly common among webcomic writers, see eg. http://questionablecontent.net/view.php?comic=2314 http://www.giantitp.com/comics/oots0864.html or https://www.irregularwebcomic.net/news.php?date=2020-05-27

#!/bin/bash
opts="${2--i}"
[[ "$1" == ?*//* ]] || { echo 'usage: sled file//script'; exit 1; }; key="${1%%//*}"; value="${1#*//}"; [[ -f "$key" ]] || { echo 'Rosebud!'; exit 1; }; sed $opts "$value" "$key" ;