yarnpkg/yarn · error · MessageError

execMissingCommand

Error message

execMissingCommand

What it means

`yarn exec` shells out to a binary in the project's resolved PATH. At `exec.js:19` it requires at least one argument (the command); `args.length < 1` throws `execMissingCommand` ('Missing command name.') before constructing the env or spawning.

Source

Thrown at src/cli/commands/exec.js:19

// @flow

import type Config from '../../config.js';
import {MessageError} from '../../errors.js';
import type {Reporter} from '../../reporters/index.js';
import * as child from '../../util/child.js';
import {makeEnv} from '../../util/execute-lifecycle-script.js';

export function setFlags(commander: Object) {}

export function hasWrapper(commander: Object, args: Array<string>): boolean {
  return true;
}

export async function run(config: Config, reporter: Reporter, flags: Object, args: Array<string>): Promise<void> {
  const env = await makeEnv(`exec`, config.cwd, config);

  if (args.length < 1) {
    throw new MessageError(reporter.lang('execMissingCommand'));
  }

  const [execName, ...rest] = args;
  await child.spawn(execName, rest, {stdio: 'inherit', env});
}

View on GitHub (pinned to c2dda503f3)

Solutions

1. Provide a command: `yarn exec eslint .`.
2. If you meant to list scripts, use `yarn run` without arguments instead.
3. In scripts, default/require the variable: `yarn exec "${CMD:?CMD required}"`.

Example fix

// before
$ yarn exec

// after
$ yarn exec eslint src

function requireExecCommand(args: string[]): string[] {
  if (!Array.isArray(args) || args.length < 1) {
    throw new Error('yarn exec requires a command name');
  }
  return args;
}

function hasExecCommand(args: unknown): args is [string, ...string[]] {
  return Array.isArray(args) && typeof args[0] === 'string' && args[0].length > 0;
}

When it happens

Trigger: Invoking `yarn exec` with no command token, e.g. `yarn exec` alone, or `yarn exec '$CMD'` where `$CMD` expands to empty.

Common situations: An npm script that calls `yarn exec` with a variable that is unset in CI, or running the command interactively by mistake.

Related errors

• missingAddDependencies
• invalidPackageName
• tooManyArguments
• tooFewArguments
• Name should not start with "/", got "${str}"

AI-assisted analysis of yarnpkg/yarn@c2dda503f3 (2026-08-13). Data as JSON: /api/errors/62478fbd587b72f3. Report an issue: GitHub.