Allow shell overrides

README.md

@@ -97,6 +97,7 @@ Check out documentation and other usage examples in the [`docs` directory](./doc
 - `options` (optional): an object containing any of the below:
   - `cwd`: the working directory to be used by all commands. Can be overridden per command.
     Default: `process.cwd()`.
+  - `shell`: shell executable used to run command strings. When unset, uses `npm_config_script_shell` if present (for example when run via `npm run`), otherwise `cmd.exe` on Windows or `/bin/sh` elsewhere. See [shell resolution](./docs/shell-resolution.md).
   - `defaultInputTarget`: the default input target when reading from `inputStream`.
     Default: `0`.
   - `handleInput`: when `true`, reads input from `process.stdin`.

bin/index.ts

@@ -96,6 +96,11 @@ const program = yargs(hideBin(process.argv))
             type: 'boolean',
             default: defaults.timings,
         },
+        shell: {
+            describe:
+                'Shell to run commands with. Defaults to cmd.exe on Windows and /bin/sh elsewhere.',
+            type: 'string',
+        },
         'passthrough-arguments': {
             alias: 'P',
             describe:
@@ -209,7 +214,20 @@ const program = yargs(hideBin(process.argv))
         },
     })
     .group(
-        ['m', 'n', 'name-separator', 's', 'r', 'no-color', 'hide', 'g', 'timings', 'P', 'teardown'],
+        [
+            'm',
+            'n',
+            'name-separator',
+            's',
+            'r',
+            'no-color',
+            'hide',
+            'g',
+            'timings',
+            'shell',
+            'P',
+            'teardown',
+        ],
         'General',
     )
     .group(['p', 'c', 'l', 't', 'pad-prefix'], 'Prefix styling')
@@ -265,6 +283,7 @@ concurrently(
         successCondition: args.success,
         timestampFormat: args.timestampFormat,
         timings: args.timings,
+        shell: args.shell,
         teardown: args.teardown,
         additionalArguments: args.passthroughArguments ? additionalArguments : undefined,
     },

docs/README.md

@@ -1,5 +1,11 @@
 # Concurrently Documentation
 
+## General
+
+These articles apply when using either concurrently's CLI or API:
+
+- [Shell Resolution](./shell-resolution.md)
+
 ## CLI
 
 These articles cover using concurrently through CLI:

docs/shell-resolution.md

@@ -0,0 +1,48 @@
+# Shell Resolution
+
+Each command runs inside a shell, not as a bare executable.
+By default, concurrently uses `cmd.exe` on Windows and `/bin/sh` elsewhere.
+
+## Using a different shell
+
+If the default shell isn't suitable, it's possible to instruct concurrently to use a specific shell in a few ways.
+
+This is useful, for example, to use Unix-style syntax (for example `BROWSER=none npm start`) on Windows, if you set concurrently shell to e.g. Git Bash.
+
+### Via explicit override
+
+An explicit shell override takes precedence over every other configuration.
+To do that, pass the `--shell` flag to the CLI:
+
+```bash
+concurrently --shell "C:\Program Files\Git\bin\bash.exe" "echo Hello world | xargs -n 1 echo"
+```
+
+Or via the API:
+
+```js
+concurrently(['echo Hello world | xargs -n 1 echo'], {
+  shell: 'C:\\Program Files\\Git\\bin\\bash.exe',
+});
+```
+
+### Via npm/pnpm/yarn v1
+
+When using npm, pnpm or yarn v1 to run concurrently via a `package.json` script, the
+[`script-shell` configuration](https://docs.npmjs.com/cli/v6/using-npm/config#script-shell) is inherited and used to spawn commands.
+
+```bash
+npm config set script-shell /bin/bash
+npm dev # Runs the dev script on bash. Concurrently will also run commands using bash.
+```
+
+## Supported shells
+
+If you've specified a different shell, concurrently detects its kind and spawns commands
+using the right syntax for that shell.
+
+The following shell types are supported:
+
+- Windows `cmd.exe`
+- Powershell
+- Any POSIX compliant shells (bash, zsh, dash, etc)

lib/concurrently.ts

@@ -23,11 +23,11 @@ import { FlowController } from './flow-control/flow-controller.js';
 import { Logger } from './logger.js';
 import { OutputWriter } from './output-writer.js';
 import { PrefixColorSelector } from './prefix-color-selector.js';
-import { getSpawnOpts, spawn } from './spawn.js';
+import { createSpawn, getSpawnOpts } from './spawn.js';
 import { castArray } from './utils.js';
 
 const defaults: ConcurrentlyOptions = {
-    spawn,
+    spawn: createSpawn(),
     kill: treeKill,
     raw: false,
     controllers: [],

lib/flow-control/teardown.spec.ts

@@ -1,26 +1,28 @@
 import { ChildProcess } from 'node:child_process';
 
-import { afterEach, describe, expect, it, Mock, vi } from 'vitest';
+import { afterEach, beforeEach, describe, expect, it, Mock, vi } from 'vitest';
 
 import { createMockInstance } from '../__fixtures__/create-mock-instance.js';
 import { createFakeProcess, FakeCommand } from '../__fixtures__/fake-command.js';
 import { SpawnCommand } from '../command.js';
 import { Logger } from '../logger.js';
-import * as spawn from '../spawn.js';
+import { getSpawnOpts } from '../spawn.js';
 import { Teardown } from './teardown.js';
 
-const spySpawn = vi
-    .spyOn(spawn, 'spawn')
-    .mockImplementation(() => createFakeProcess(1) as ChildProcess) as Mock;
+let spawn: Mock<SpawnCommand>;
 const logger = createMockInstance(Logger);
 const commands = [new FakeCommand()];
 const teardown = 'cowsay bye';
 
+beforeEach(() => {
+    spawn = vi.fn(() => createFakeProcess(1) as ChildProcess);
+});
+
 afterEach(() => {
     vi.clearAllMocks();
 });
 
-const create = (teardown: string[], spawn?: SpawnCommand) =>
+const create = (teardown: string[]) =>
     new Teardown({
         spawn,
         logger,
@@ -35,23 +37,17 @@ it('returns commands unchanged', () => {
 describe('onFinish callback', () => {
     it('does not spawn nothing if there are no teardown commands', () => {
         create([]).handle(commands).onFinish();
-        expect(spySpawn).not.toHaveBeenCalled();
+        expect(spawn).not.toHaveBeenCalled();
     });
 
     it('runs teardown command', () => {
         create([teardown]).handle(commands).onFinish();
-        expect(spySpawn).toHaveBeenCalledWith(teardown, spawn.getSpawnOpts({ stdio: 'raw' }));
-    });
-
-    it('runs teardown command with custom spawn function', () => {
-        const customSpawn = vi.fn(() => createFakeProcess(1));
-        create([teardown], customSpawn).handle(commands).onFinish();
-        expect(customSpawn).toHaveBeenCalledWith(teardown, spawn.getSpawnOpts({ stdio: 'raw' }));
+        expect(spawn).toHaveBeenCalledWith(teardown, getSpawnOpts({ stdio: 'raw' }));
     });
 
     it('waits for teardown command to close', async () => {
         const child = createFakeProcess(1);
-        spySpawn.mockReturnValue(child);
+        spawn.mockReturnValue(child);
 
         const result = create([teardown]).handle(commands).onFinish();
         child.emit('close', 1, null);
@@ -60,7 +56,7 @@ describe('onFinish callback', () => {
 
     it('rejects if teardown command errors (string)', async () => {
         const child = createFakeProcess(1);
-        spySpawn.mockReturnValue(child);
+        spawn.mockReturnValue(child);
 
         const result = create([teardown]).handle(commands).onFinish();
         const error = 'fail';
@@ -71,7 +67,7 @@ describe('onFinish callback', () => {
 
     it('rejects if teardown command errors (error)', async () => {
         const child = createFakeProcess(1);
-        spySpawn.mockReturnValue(child);
+        spawn.mockReturnValue(child);
 
         const result = create([teardown]).handle(commands).onFinish();
         const error = new Error('fail');
@@ -84,7 +80,7 @@ describe('onFinish callback', () => {
 
     it('rejects if teardown command errors (error, no stack)', async () => {
         const child = createFakeProcess(1);
-        spySpawn.mockReturnValue(child);
+        spawn.mockReturnValue(child);
 
         const result = create([teardown]).handle(commands).onFinish();
         const error = new Error('fail');
@@ -97,32 +93,32 @@ describe('onFinish callback', () => {
     it('runs multiple teardown commands in sequence', async () => {
         const child1 = createFakeProcess(1);
         const child2 = createFakeProcess(2);
-        spySpawn.mockReturnValueOnce(child1).mockReturnValueOnce(child2);
+        spawn.mockReturnValueOnce(child1).mockReturnValueOnce(child2);
 
         const result = create(['foo', 'bar']).handle(commands).onFinish();
 
-        expect(spySpawn).toHaveBeenCalledTimes(1);
-        expect(spySpawn).toHaveBeenLastCalledWith('foo', spawn.getSpawnOpts({ stdio: 'raw' }));
+        expect(spawn).toHaveBeenCalledTimes(1);
+        expect(spawn).toHaveBeenLastCalledWith('foo', getSpawnOpts({ stdio: 'raw' }));
 
         child1.emit('close', 1, null);
         await new Promise((resolve) => setTimeout(resolve));
 
-        expect(spySpawn).toHaveBeenCalledTimes(2);
-        expect(spySpawn).toHaveBeenLastCalledWith('bar', spawn.getSpawnOpts({ stdio: 'raw' }));
+        expect(spawn).toHaveBeenCalledTimes(2);
+        expect(spawn).toHaveBeenLastCalledWith('bar', getSpawnOpts({ stdio: 'raw' }));
 
         child2.emit('close', 0, null);
         await expect(result).resolves.toBeUndefined();
     });
 
     it('stops running teardown commands on SIGINT', async () => {
         const child = createFakeProcess(1);
-        spySpawn.mockReturnValue(child);
+        spawn.mockReturnValue(child);
 
         const result = create(['foo', 'bar']).handle(commands).onFinish();
         child.emit('close', null, 'SIGINT');
         await result;
 
-        expect(spySpawn).toHaveBeenCalledTimes(1);
-        expect(spySpawn).toHaveBeenLastCalledWith('foo', expect.anything());
+        expect(spawn).toHaveBeenCalledTimes(1);
+        expect(spawn).toHaveBeenLastCalledWith('foo', expect.anything());
     });
 });

lib/flow-control/teardown.ts

@@ -2,7 +2,7 @@ import Rx from 'rxjs';
 
 import { Command, SpawnCommand } from '../command.js';
 import { Logger } from '../logger.js';
-import { getSpawnOpts, spawn as baseSpawn } from '../spawn.js';
+import { getSpawnOpts } from '../spawn.js';
 import { FlowController } from './flow-controller.js';
 
 export class Teardown implements FlowController {
@@ -18,13 +18,12 @@ export class Teardown implements FlowController {
         logger: Logger;
         /**
          * Which function to use to spawn commands.
-         * Defaults to the same used by the rest of concurrently.
          */
-        spawn?: SpawnCommand;
+        spawn: SpawnCommand;
         commands: readonly string[];
     }) {
         this.logger = logger;
-        this.spawn = spawn || baseSpawn;
+        this.spawn = spawn;
         this.teardown = commands;
     }
 

lib/index.ts

@@ -22,9 +22,13 @@ import { OutputErrorHandler } from './flow-control/output-error-handler.js';
 import { RestartDelay, RestartProcess } from './flow-control/restart-process.js';
 import { Teardown } from './flow-control/teardown.js';
 import { Logger } from './logger.js';
+import { createSpawn } from './spawn.js';
 import { castArray } from './utils.js';
 
-export type ConcurrentlyOptions = Omit<BaseConcurrentlyOptions, 'abortSignal' | 'hide'> & {
+export type ConcurrentlyOptions = Omit<
+    BaseConcurrentlyOptions,
+    'abortSignal' | 'hide' | 'spawn'
+> & {
     // Logger options
     /**
      * Which command(s) should have their output hidden.
@@ -120,6 +124,13 @@ export type ConcurrentlyOptions = Omit<BaseConcurrentlyOptions, 'abortSignal' |
      * If not defined, no argument replacing will happen.
      */
     additionalArguments?: string[];
+
+    /**
+     * Shell executable used to run command strings.
+     * When unset, uses the `npm_config_script_shell` env variable if present. Otherwise, falls back
+     * to `cmd.exe` on Windows, and `/bin/sh` elsewhere.
+     */
+    shell?: string;
 };
 
 export function concurrently(
@@ -157,11 +168,13 @@ export function concurrently(
     const abortController = new AbortController();
     const outputStream = options.outputStream || process.stdout;
 
+    const spawn = createSpawn(options.shell);
     return createConcurrently(commands, {
         maxProcesses: options.maxProcesses,
         raw: options.raw,
         successCondition: options.successCondition,
         cwd: options.cwd,
+        spawn,
         hide,
         logger,
         outputStream,
@@ -198,7 +211,7 @@ export function concurrently(
                 logger: options.timings ? logger : undefined,
                 timestampFormat: options.timestampFormat,
             }),
-            new Teardown({ logger, spawn: options.spawn, commands: options.teardown || [] }),
+            new Teardown({ logger, spawn, commands: options.teardown || [] }),
         ],
         prefixColors: options.prefixColors || [],
         additionalArguments: options.additionalArguments,