<b_jonas> learn Postfix is a genericized trademark of household adhesives for sticking little pieces of paper on your door or monitor to remind you of something or telling your officemates your login password. Called Tack-it in the U.S.

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