denoland-deno/docs/examples/subprocess.md

Run subprocess

API Reference

Example:

// create subprocess
const p = Deno.run({
  cmd: ["echo", "hello"],
});

// await its completion
await p.status();

Run it:

$ deno run --allow-run ./subprocess_simple.ts
hello

Here a function is assigned to window.onload. This function is called after the main script is loaded. This is the same as onload of the browsers, and it can be used as the main entrypoint.

By default when you use Deno.run() subprocess inherits stdin, stdout and stderr of parent process. If you want to communicate with started subprocess you can use "piped" option.

const fileNames = Deno.args;

const p = Deno.run({
  cmd: [
    "deno",
    "run",
    "--allow-read",
    "https://deno.land/std/examples/cat.ts",
    ...fileNames,
  ],
  stdout: "piped",
  stderr: "piped",
});

const { code } = await p.status();

if (code === 0) {
  const rawOutput = await p.output();
  await Deno.stdout.write(rawOutput);
} else {
  const rawError = await p.stderrOutput();
  const errorString = new TextDecoder().decode(rawError);
  console.log(errorString);
}

Deno.exit(code);

When you run it:

$ deno run --allow-run ./subprocess.ts <somefile>
[file content]

$ deno run --allow-run ./subprocess.ts non_existent_file.md

Uncaught NotFound: No such file or directory (os error 2)
    at DenoError (deno/js/errors.ts:22:5)
    at maybeError (deno/js/errors.ts:41:12)
    at handleAsyncMsgFromRust (deno/js/dispatch.ts:27:17)