Why Aren't Dynamic Variables Evaluated in My n8n Execute Command Node?

It sounds like your Execute Command node isn’t evaluating the expression you’re using and instead is passing the literal string (e.g. "json.variable") to your command. In other words, the expected dynamic substitution isn’t happening. Here are a few things to check:

1. Enable Expression Mode
   Make sure that for the Command parameter you’re using the expression editor. In n8n select the gear icon (or “Add Expression”) next to the field so that you can wrap your dynamic value in double curly brackets. For example, if you want to use a value from the JSON from a previous node, you’d set it up like:

   BASHCopied
   copy /temp/{{ $json["uploadPath"] }} /sorted/{{ $json["dateFolder"] }}

   This tells n8n to evaluate the expression and insert the actual value rather than the literal text.

2. Command Field Formatting
   Verify that there aren’t any extra quotes or escaping issues that might prevent the expression from being parsed. Sometimes if you wrap the entire command in quotes (or use single quotes where evaluation isn’t supported) the node won’t replace the expression.

3. Workflow Execution Mode
   Since you’re running via npm on Windows, make sure that the shell you’re using (typically CMD on Windows) isn’t interfering with the expression evaluation. Although the node itself handles the variable substitution before running the command, it’s good to check that all your commands (especially if you use chained commands) are formatted correctly.

4. Node Configuration and Execution Once
   If your node is configured to “Execute Once” while you’re expecting per-item execution, the JSON used for substitution may not be what you expect. Double-check your setting here to ensure that each item’s values (the ones you use in the expressions) are available at run time.

In short, switching your Command parameter to expression mode and using the proper n8n expression syntax (i.e. double curly brackets with the $json property) will ensure that the extracted folder name (e.g. “2025_02_09”) or any other value is correctly passed to your copy command.