How to Use the -A Flag in Deno for Full Permissions

In Deno, the -A flag grants full permissions to your script, allowing it to access files, network, environment variables, and more without restrictions. Use it by running deno run -A your_script.ts. This flag is a shortcut for --allow-all.

Syntax

The -A flag is used with the deno run command to grant all permissions to the script. It is a shorthand for --allow-all.

• deno run -A script.ts: Runs script.ts with full permissions.
• -A enables all permission types including file, network, environment, and more.

bash

deno run -A script.ts

Example

This example shows a Deno script that reads a file and fetches data from the internet. Using -A allows both file and network access without separate permission flags.

typescript

import { readTextFile } from "https://deno.land/std/fs/mod.ts";

async function main() {
  const fileContent = await Deno.readTextFile("example.txt");
  console.log("File content:", fileContent);

  const response = await fetch("https://api.github.com");
  const data = await response.json();
  console.log("GitHub API status:", data.current_user_url);
}

main();

Output

File content: Hello from example.txt
GitHub API status: https://api.github.com/user

Common Pitfalls

Using -A grants full permissions, which can be risky if running untrusted code. Avoid using -A unless necessary. Instead, prefer specific permission flags like --allow-read or --allow-net for better security.

Also, forgetting to use -A or the needed permission flags causes permission errors when the script tries to access restricted resources.

bash

/* Wrong: No permissions granted, will cause error */
denorun script.ts

/* Right: Grant only needed permissions */
denorun --allow-read --allow-net script.ts

/* Shortcut: Grant all permissions */
denorun -A script.ts

Quick Reference

Flag	Description
-A or --allow-all	Grants all permissions (file, network, env, etc.)
--allow-read	Allows reading files from disk
--allow-write	Allows writing files to disk
--allow-net	Allows network access
--allow-env	Allows access to environment variables

Key Takeaways

Use -A to grant full permissions to your Deno script quickly.

Avoid -A for untrusted code to keep your system safe.

Grant only the permissions your script needs using specific flags when possible.

Without proper permissions, Deno scripts will throw errors when accessing restricted resources.

The -A flag is a shortcut for --allow-all.