convert custom script into overlay

flake.nix

@@ -24,6 +24,17 @@
         system,
         ...
       }: rec {
+        _module.args.pkgs = import inputs.nixpkgs {
+          inherit system;
+          overlays = [
+            (_final: prev: {
+              nuget-to-json = prev.nuget-to-json.overrideAttrs (old: {
+                src = ./nuget-to-json.sh;
+              });
+            })
+          ];
+          config = {};
+        };
         # Per-system attributes can be defined here. The self' and inputs'
         # module parameters provide easy access to attributes of the same
         # system.

nuget-to-json.sh

@@ -1,11 +1,11 @@
-#!/nix/store/ciarnmsx8lvsrmdbjddpmx0pqjrm8imb-bash-5.3p3/bin/bash
+#!@runtimeShell@
 # shellcheck shell=bash
 
 set -euo pipefail
 shopt -s nullglob
 
-export SSL_CERT_FILE=/nix/store/6jsh5hyyli9ddac6dqxx07a68jzllkqb-nss-cacert-3.115/etc/ssl/certs/ca-bundle.crt
-export PATH="/nix/store/rqn7v98b071xg19iyrz3qzlby8nwmqh3-nix-2.31.2/bin:/nix/store/xs8scz9w9jp4hpqycx3n3bah5y07ymgj-coreutils-9.8/bin:/nix/store/frzsv47z1mcyrp941zab08mx6kardizi-jq-1.8.1-bin/bin:/nix/store/69j5n7qzjlphqpgsx4bbbp6zcklm7cih-xmlstarlet-1.6.1/bin:/nix/store/xvh4bi0cc2cw18lpn6ax9m4zwnn1s9lj-curl-8.16.0-bin/bin:/nix/store/22r4s6lqhl43jkazn51f3c18qwk894g4-gnugrep-3.12/bin:/nix/store/8c4l9cqqj7pixqlmljx5d495pfpw8pys-gawk-5.3.2/bin:$PATH"
+export SSL_CERT_FILE=@cacert@/etc/ssl/certs/ca-bundle.crt
+export PATH="@binPath@:$PATH"
 # used for glob ordering of package names
 export LC_ALL=C