diff --git a/docs/manual-zh/src/package/pre-build.md b/docs/manual-zh/src/package/pre-build.md
index 88830a0d..42956dfe 100644
--- a/docs/manual-zh/src/package/pre-build.md
+++ b/docs/manual-zh/src/package/pre-build.md
@@ -12,7 +12,7 @@
     {
       "input": "a.txt",
       "output": "a.mbt",
-      "command": ":embed -i ${input} -o ${output}"
+      "command": ":embed -i $input -o $output"
     }
   ]
 }