Interface: ChildProcessAPI

Defined in: packages/core/src/runtime.ts:249

Child process operations interface Subset of Node.js child_process module

Properties

spawn()

spawn: {(command, options?): ChildProcessWithoutNullStreams; (command, options): ChildProcessByStdio<Writable, Readable, Readable>; (command, options): ChildProcessByStdio<Writable, Readable, null>; (command, options): ChildProcessByStdio<Writable, null, Readable>; (command, options): ChildProcessByStdio<null, Readable, Readable>; (command, options): ChildProcessByStdio<Writable, null, null>; (command, options): ChildProcessByStdio<null, Readable, null>; (command, options): ChildProcessByStdio<null, null, Readable>; (command, options): ChildProcessByStdio<null, null, null>; (command, options): ChildProcess; (command, args?, options?): ChildProcessWithoutNullStreams; (command, args, options): ChildProcessByStdio<Writable, Readable, Readable>; (command, args, options): ChildProcessByStdio<Writable, Readable, null>; (command, args, options): ChildProcessByStdio<Writable, null, Readable>; (command, args, options): ChildProcessByStdio<null, Readable, Readable>; (command, args, options): ChildProcessByStdio<Writable, null, null>; (command, args, options): ChildProcessByStdio<null, Readable, null>; (command, args, options): ChildProcessByStdio<null, null, Readable>; (command, args, options): ChildProcessByStdio<null, null, null>; (command, args, options): ChildProcess; }

Defined in: packages/core/src/runtime.ts:250

Call Signature

(command, options?): ChildProcessWithoutNullStreams

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use cwd to specify the working directory from which the process is spawned. If not given, the default is to inherit the current working directory. If given, but the path does not exist, the child process emits an ENOENT error and exits immediately. ENOENT is also emitted when the command does not exist.

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

Node.js overwrites argv[0] with process.execPath on startup, so process.argv[0] in a Node.js child process will not match the argv0 parameter passed to spawn from the parent. Retrieve it with the process.argv0 property instead.

If the signal option is enabled, calling .abort() on the corresponding AbortController is similar to calling .kill() on the child process except the error passed to the callback will be an AbortError:

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options?

SpawnOptionsWithoutStdio

Returns

ChildProcessWithoutNullStreams

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<Writable, Readable, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioPipe, StdioPipe>

Returns

ChildProcessByStdio<Writable, Readable, Readable>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<Writable, Readable, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioPipe, StdioNull>

Returns

ChildProcessByStdio<Writable, Readable, null>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<Writable, null, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioNull, StdioPipe>

Returns

ChildProcessByStdio<Writable, null, Readable>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<null, Readable, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioPipe, StdioPipe>

Returns

ChildProcessByStdio<null, Readable, Readable>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<Writable, null, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioNull, StdioNull>

Returns

ChildProcessByStdio<Writable, null, null>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<null, Readable, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioPipe, StdioNull>

Returns

ChildProcessByStdio<null, Readable, null>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<null, null, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioNull, StdioPipe>

Returns

ChildProcessByStdio<null, null, Readable>

Since

v0.1.90

Call Signature

(command, options): ChildProcessByStdio<null, null, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioNull, StdioNull>

Returns

ChildProcessByStdio<null, null, null>

Since

v0.1.90

Call Signature

(command, options): ChildProcess

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

options

SpawnOptions

Returns

ChildProcess

Since

v0.1.90

Call Signature

(command, args?, options?): ChildProcessWithoutNullStreams

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args?

readonly string[]

List of string arguments.

options?

SpawnOptionsWithoutStdio

Returns

ChildProcessWithoutNullStreams

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<Writable, Readable, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioPipe, StdioPipe>

Returns

ChildProcessByStdio<Writable, Readable, Readable>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<Writable, Readable, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioPipe, StdioNull>

Returns

ChildProcessByStdio<Writable, Readable, null>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<Writable, null, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioNull, StdioPipe>

Returns

ChildProcessByStdio<Writable, null, Readable>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<null, Readable, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioPipe, StdioPipe>

Returns

ChildProcessByStdio<null, Readable, Readable>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<Writable, null, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioPipe, StdioNull, StdioNull>

Returns

ChildProcessByStdio<Writable, null, null>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<null, Readable, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioPipe, StdioNull>

Returns

ChildProcessByStdio<null, Readable, null>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<null, null, Readable>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioNull, StdioPipe>

Returns

ChildProcessByStdio<null, null, Readable>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcessByStdio<null, null, null>

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptionsWithStdioTuple<StdioNull, StdioNull, StdioNull>

Returns

ChildProcessByStdio<null, null, null>

Since

v0.1.90

Call Signature

(command, args, options): ChildProcess

The child_process.spawn() method spawns a new process using the given command, with command-line arguments in args. If omitted, args defaults to an empty array.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

A third argument may be used to specify additional options, with these defaults:

const defaults = {
  cwd: undefined,
  env: process.env,
};

Use env to specify environment variables that will be visible to the new process, the default is process.env.

undefined values in env will be ignored.

Example of running ls -lh /usr, capturing stdout, stderr, and the exit code:

import { spawn } from 'node:child_process';
const ls = spawn('ls', ['-lh', '/usr']);

ls.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

ls.stderr.on('data', (data) => {
  console.error(`stderr: ${data}`);
});

ls.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

Example: A very elaborate way to run ps ax | grep ssh

import { spawn } from 'node:child_process';
const ps = spawn('ps', ['ax']);
const grep = spawn('grep', ['ssh']);

ps.stdout.on('data', (data) => {
  grep.stdin.write(data);
});

ps.stderr.on('data', (data) => {
  console.error(`ps stderr: ${data}`);
});

ps.on('close', (code) => {
  if (code !== 0) {
    console.log(`ps process exited with code ${code}`);
  }
  grep.stdin.end();
});

grep.stdout.on('data', (data) => {
  console.log(data.toString());
});

grep.stderr.on('data', (data) => {
  console.error(`grep stderr: ${data}`);
});

grep.on('close', (code) => {
  if (code !== 0) {
    console.log(`grep process exited with code ${code}`);
  }
});

Example of checking for failed spawn:

import { spawn } from 'node:child_process';
const subprocess = spawn('bad_command');

subprocess.on('error', (err) => {
  console.error('Failed to start subprocess.');
});

Certain platforms (macOS, Linux) will use the value of argv[0] for the process title while others (Windows, SunOS) will use command.

import { spawn } from 'node:child_process';
const controller = new AbortController();
const { signal } = controller;
const grep = spawn('grep', ['ssh'], { signal });
grep.on('error', (err) => {
  // This will be called with err being an AbortError if the controller aborts
});
controller.abort(); // Stops the child process

Parameters

command

string

The command to run.

args

readonly string[]

List of string arguments.

options

SpawnOptions

Returns

ChildProcess

Since

v0.1.90

execSync()

execSync: {(command): Buffer; (command, options): string; (command, options): Buffer; (command, options?): string | Buffer; }

Defined in: packages/core/src/runtime.ts:251

Call Signature

(command): Buffer

The child_process.execSync() method is generally identical to exec with the exception that the method will not return until the child process has fully closed. When a timeout has been encountered and killSignal is sent, the method won't return until the process has completely exited. If the child process intercepts and handles the SIGTERM signal and doesn't exit, the parent process will wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw. The Error object will contain the entire result from spawnSync.

Never pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

command

string

The command to run.

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(command, options): string

If the process times out or has a non-zero exit code, this method will throw. The Error object will contain the entire result from spawnSync.

Never pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

command

string

The command to run.

options

ExecSyncOptionsWithStringEncoding

Returns

string

The stdout from the command.

Since

v0.11.12

Call Signature

(command, options): Buffer

If the process times out or has a non-zero exit code, this method will throw. The Error object will contain the entire result from spawnSync.

Never pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

command

string

The command to run.

options

ExecSyncOptionsWithBufferEncoding

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(command, options?): string | Buffer

If the process times out or has a non-zero exit code, this method will throw. The Error object will contain the entire result from spawnSync.

Never pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

command

string

The command to run.

options?

ExecSyncOptions

Returns

string | Buffer

The stdout from the command.

Since

v0.11.12

execFileSync()

execFileSync: {(file): Buffer; (file, options): string; (file, options): Buffer; (file, options?): string | Buffer; (file, args): Buffer; (file, args, options): string; (file, args, options): Buffer; (file, args?, options?): string | Buffer; }

Defined in: packages/core/src/runtime.ts:252

Call Signature

(file): Buffer

The child_process.execFileSync() method is generally identical to execFile with the exception that the method will not return until the child process has fully closed. When a timeout has been encountered and killSignal is sent, the method won't return until the process has completely exited.

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(file, options): string

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

options

ExecFileSyncOptionsWithStringEncoding

Returns

string

The stdout from the command.

Since

v0.11.12

Call Signature

(file, options): Buffer

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

options

ExecFileSyncOptionsWithBufferEncoding

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(file, options?): string | Buffer

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

options?

ExecFileSyncOptions

Returns

string | Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(file, args): Buffer

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

args

readonly string[]

List of string arguments.

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(file, args, options): string

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

args

readonly string[]

List of string arguments.

options

ExecFileSyncOptionsWithStringEncoding

Returns

string

The stdout from the command.

Since

v0.11.12

Call Signature

(file, args, options): Buffer

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

args

readonly string[]

List of string arguments.

options

ExecFileSyncOptionsWithBufferEncoding

Returns

Buffer

The stdout from the command.

Since

v0.11.12

Call Signature

(file, args?, options?): string | Buffer

If the child process intercepts and handles the SIGTERM signal and does not exit, the parent process will still wait until the child process has exited.

If the process times out or has a non-zero exit code, this method will throw an Error that will include the full result of the underlying spawnSync.

If the shell option is enabled, do not pass unsanitized user input to this function. Any input containing shell metacharacters may be used to trigger arbitrary command execution.

Parameters

file

string

The name or path of the executable file to run.

args?

readonly string[]

List of string arguments.

options?

ExecFileSyncOptions

Returns

string | Buffer

The stdout from the command.

Since

v0.11.12

Properties​

spawn()​

Call Signature​

Parameters​

command​

options?​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

args?​

options?​

Returns​

Since​

Call Signature​

Parameters​

command​

args​

options​

Returns​

Since​

Call Signature​

Parameters​

command​

args​

Properties

spawn()

Call Signature

Parameters

command

options?

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

options

Returns

Since

Call Signature

Parameters

command

args?

options?

Returns

Since

Call Signature

Parameters

command

args

options

Returns

Since

Call Signature

Parameters

command

args