--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tmp/mk	Sat May 22 19:29:10 2021 -0500
@@ -0,0 +1,1 @@
+​[[ "$1" == ?*//* ]] || { echo usage: "mk[x]" file//contents >&2; exit 1; }; key="${1%%//*}"; value="${1#*//}"; echo "$value" > "$(echo-p "$key")" && echo "$key"
\ No newline at end of file