From 5b510c550dcf203521061c626aa1fa9906b82298 Mon Sep 17 00:00:00 2001
From: James Andariese <james@strudelline.net>
Date: Mon, 17 Oct 2022 10:42:06 -0500
Subject: [PATCH] add script-interpreter

---
 script-interpreter.nix | 14 ++++++++++++++
 1 file changed, 14 insertions(+)
 create mode 100644 script-interpreter.nix

diff --git a/script-interpreter.nix b/script-interpreter.nix
new file mode 100644
index 0000000..f3929ae
--- /dev/null
+++ b/script-interpreter.nix
@@ -0,0 +1,14 @@
+with builtins;
+
+let file-lines = import ./file-lines.nix; in
+
+f: ( let n = head (split-filename f); in
+    let
+      lines = file-lines f;
+      firstLine = head lines;
+      shebangMatch = match ''#! *(.*[/])?(([\][ ]|[^ /])*)( (.*))?'' firstLine;
+    in
+      if shebangMatch == null
+        then rec { interpreter = "sh"; args = "";}
+        else rec { interpreter = (elemAt shebangMatch 1); args = (elemAt shebangMatch 4);}
+  )