diff --git a/package.json b/package.json
index ecc650dc..2f2785dd 100644
--- a/package.json
+++ b/package.json
@@ -71,7 +71,7 @@
     "test:ci": "mocha --recursive ./test --require ./test/mocha-root-hooks.mjs --reporter mocha-multi-reporters --reporter-options configFile=./test/config/reporter.json",
     "build": "npm run build:app && npm run build:sea",
     "build:app": "esbuild --bundle ./src/user-entrypoint.mjs --platform=node --outfile=./dist/cli.cjs --format=cjs --inject:./sea/import-meta-url.js --define:import.meta.url=importMetaUrl",
-    "postbuild:app": "sed -i '' '1s/.*/#!\\/usr\\/bin\\/env NODE_NO_WARNINGS=1 node/' ./dist/cli.cjs",
+    "postbuild:app": "node ./scripts/update-prod-hashbang.mjs",
     "build:sea": "node ./sea/build.cjs",
     "format": "prettier -w ."
   },
diff --git a/scripts/update-prod-hashbang.mjs b/scripts/update-prod-hashbang.mjs
new file mode 100644
index 00000000..350412b5
--- /dev/null
+++ b/scripts/update-prod-hashbang.mjs
@@ -0,0 +1,15 @@
+#!/usr/bin/env node
+import * as fs from "node:fs";
+import * as path from "node:path";
+
+const __dirname = import.meta.dirname;
+
+const filePath = path.resolve(path.join(__dirname, "../dist/cli.cjs"));
+let fileContents = fs.readFileSync(filePath);
+const endOfFirstLine = fileContents.indexOf("\n");
+fileContents = fileContents.slice(endOfFirstLine);
+fileContents = `#!/usr/bin/env NODE_NO_WARNINGS=1 node\n${fileContents}`;
+fs.rmSync(filePath);
+fs.writeFileSync(filePath, fileContents, {
+  mode: 755,
+});
diff --git a/test/general-cli.mjs b/test/general-cli.mjs
index 81c3a1cb..971e95c4 100644
--- a/test/general-cli.mjs
+++ b/test/general-cli.mjs
@@ -128,6 +128,7 @@ describe("cli operations", function () {
   it("enables nodeJS warnings from the dev entrypoint", async function () {
     let stderr = spawnSync("./src/user-entrypoint.mjs", ["warn"], {
       encoding: "utf8",
+      shell: true,
       stdio: "pipe",
     }).stderr;
 
@@ -140,6 +141,7 @@ describe("cli operations", function () {
   it("suppresses nodeJS warnings from the prod entrypoint", async function () {
     let stderr = spawnSync("./dist/cli.cjs", ["warn"], {
       encoding: "utf8",
+      shell: true,
       stdio: "pipe",
     }).stderr;