> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/build/local-file-trigger.md).

# Watch host files with Local File Trigger

In Duaer, Local File Trigger starts the digital organization on host filesystem changes. Paths are on the machine that runs Duaer, not the computer in your browser.
## Watch a folder

1. Search for Local File Trigger and place it at the start of the canvas.
2. Set Trigger On to Changes Involving a Specific Folder.
3. Set Folder to Watch to a host path, for example /data/invoices.
4. Under Watch for, select the events you need (for example File Added).
5. Select Execute step, then change a file in that folder to test. Publish so it keeps listening.

You can also choose Changes to a Specific File and set File to Watch.

Ignore Existing Files/Folders under Options defaults to on. Hosted instances may not allow arbitrary host paths.

To read existing files, see [Read and write host files in Duaer](/build/read-write-files-from-disk.md).
## Questions

### Can Local File Trigger in Duaer watch my laptop Desktop?

No. It watches the host that runs Duaer. For laptop files, self-host, or upload somewhere reachable first.

## Related

- [Read and write host files in Duaer](https://doc.duaer.com/build/read-write-files-from-disk.md)
- [Transfer files with FTP in Duaer](https://doc.duaer.com/build/ftp.md)
- [Run a host command with Execute Command in Duaer](https://doc.duaer.com/build/execute-command.md)