From 9f96a331e3b30fde3ffd73c278cb4dd4bcd26c07 Mon Sep 17 00:00:00 2001
From: Kit Langton <kit.langton@gmail.com>
Date: Mon, 26 Oct 2026 10:01:47 -0700
Subject: [PATCH] fix(core): stop custom commands from overwriting $0 and
 re-filling $ARGUMENTS you typed (#59198)

---
 packages/core/src/config/plugin/command.ts |  7 ++++---
 packages/core/test/config/command.test.ts  | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/config/plugin/command.ts b/packages/core/src/config/plugin/command.ts
index 9d739ac8c51..c13ff4a5b02 100644
--- a/packages/core/src/config/plugin/command.ts
+++ b/packages/core/src/config/plugin/command.ts
@@ -193,14 +193,14 @@ function evaluateTemplate(
     const args = parseArguments(input)
     const placeholders = template.match(placeholderRegex) ?? []
     const last = Math.max(0, ...placeholders.map((item) => Number(item.slice(1))))
-    const expanded = template.replaceAll(placeholderRegex, (_, index) => {
+    const withArguments = template.replaceAll(argumentRegex, (match, index) => {
+      if (match === "$ARGUMENTS") return input
       const position = Number(index)
       const argIndex = position - 1
       if (argIndex >= args.length) return ""
       if (position === last) return args.slice(argIndex).join(" ")
       return args[argIndex]
     })
-    const withArguments = expanded.replaceAll("$ARGUMENTS", () => input)
     const text =
       placeholders.length === 0 && !template.includes("$ARGUMENTS") && input.trim()
         ? `${withArguments}\n\n${input}`.trim()
@@ -239,6 +239,7 @@ function parseArguments(input: string) {
 }
 
 const argsRegex = /(?:\[Image\s+\d+\]|"[^"]*"|'[^']*'|[^\s"']+)/gi
-const placeholderRegex = /\$(\d+)/g
+const placeholderRegex = /\$([1-9]\d*)/g
+const argumentRegex = /\$(?:ARGUMENTS|([1-9]\d*))/g
 const quoteTrimRegex = /^["']|["']$/g
 const shellRegex = /!`([^`]+)`/g
diff --git a/packages/core/test/config/command.test.ts b/packages/core/test/config/command.test.ts
index 9d80adbfb75..cf77c83690c 100644
--- a/packages/core/test/config/command.test.ts
+++ b/packages/core/test/config/command.test.ts
@@ -89,6 +89,21 @@ describe("ConfigCommandPlugin.Plugin", () => {
       input: '"alpha beta" gamma delta',
       expected: "First alpha beta. Rest gamma delta.",
     },
+    {
+      template: "Run awk '{print $0}' on $1.",
+      input: "app.log",
+      expected: "Run awk '{print $0}' on app.log.",
+    },
+    {
+      template: "Run awk '{print $0}'.",
+      input: "app.log",
+      expected: "Run awk '{print $0}'.\n\napp.log",
+    },
+    {
+      template: "First $1. Rest $2.",
+      input: '"$ARGUMENTS" tail',
+      expected: "First $ARGUMENTS. Rest tail.",
+    },
     { template: "$ARGUMENTS / $ARGUMENTS", input: "$& $$", expected: "$& $$ / $& $$" },
   ]) {
     it.live(`interpolates ${JSON.stringify(item.template)} with literal input ${JSON.stringify(item.input)}`, () =>