pkgs.writeAshScript is similar to writeShellScript but busybox

pkgs/write-ash-script/default.nix

@@ -0,0 +1,14 @@
+{
+  busybox
+, writeScript
+, lib
+}
+: name : { runtimeInputs ? [] } : text : writeScript name ''
+#!${busybox}/bin/sh
+set -o errexit
+set -o nounset
+set -o pipefail
+
+export PATH="${lib.makeBinPath ([ busybox ] ++ runtimeInputs)}:$PATH"
+${text}
+''