How do I run an arbitrary shell command from Deno?

I want to run any arbitrary bash command from Deno, like I would with a child_process in Node. Is that possible in Deno?

Solution

Deno 1.28.0 added a new API to run a shell command: Deno.Command (--allow-run permission required)

let cmd = new Deno.Command("echo", { args: ["hello world"] });
let { code, stdout, stderr } = await cmd.output();
// stdout & stderr are a Uint8Array
console.log(new TextDecoder().decode(stdout)); // hello world

More advanced usage:

const command = new Deno.Command(Deno.execPath(), {
  args: [
    "eval",
    "console.log('Hello World')",
  ],
  stdin: "piped",
  stdout: "piped",
});
const child = command.spawn();

// open a file and pipe the subprocess output to it.
child.stdout.pipeTo(
  Deno.openSync("output", { write: true, create: true }).writable,
);

// manually close stdin
child.stdin.close();
const status = await child.status;

const s = await c.status;
console.log(s);

This API replaced the deprecated Deno.run

OLD ANSWER:

In order to run a shell command, you have to use Deno.run, which requires --allow-run permissions.

There's an ongoing discussion to use --allow-all instead for running a subprocess

The following will output to stdout.

// --allow-run
const process = Deno.run({
  cmd: ["echo", "hello world"]
});

// Close to release Deno's resources associated with the process.
// The process will continue to run after close(). To wait for it to
// finish `await process.status()` or `await process.output()`.
process.close();

If you want to store the output, you'll have to set stdout/stderr to "piped"

const process = Deno.run({
  cmd: ["echo", "hello world"], 
  stdout: "piped",
  stderr: "piped"
});


const output = await process.output() // "piped" must be set
const outStr = new TextDecoder().decode(output);

/* 
const error = await p.stderrOutput();
const errorStr = new TextDecoder().decode(error); 
*/

process.close();