Since npm 5.1

npm config set script-shell "C:\\Program Files (x86)\\git\\bin\\bash.exe"  

or (64bit installation)

npm config set script-shell "C:\\Program Files\\git\\bin\\bash.exe"

Note that you need to have git for windows installed.

You can revert it by running:

npm config delete script-shell

Here's one way to do it:

1. Create a script, such as my_script.sh, in your project bin directory.

2. In your package.json file, add a line to run the script using bash. For example:

   "scripts": {
     "boogie": "bash bin/my_script.sh"
   }
   

Now you can run your bash script from npm by:

    npm run-script boogie

Not very elegant, but it works.

If you are developing in both Windows and Linux/Unix, then at least this approach is fairly portable to both environments.

Ideally, overriding the npm shell config parameter should work, but npm (at least version 1.4.14) seems in Windows to ignore the setting and use cmd.exe instead.

Use the following command in your bash or Git Bash shell to find out the shell setting:

$ npm config ls -l | grep shell

By default, the output will be:

shell = "C:\\WINDOWS\\system32\\cmd.exe"

However, to override the default shell parameter, you can add (or edit) an npmrc file to the \Users\yourusername\AppData\Roaming\npm\etc directory. Just add the following line:

shell = "C:\\Program Files (x86)\\git\\bin\\bash.exe"

The path you use can be any valid path to bash.exe. Now, if you run the above "npm config ls -l | grep shell" command, you will see the following output, indicating that the shell parameter has been overriden:

shell = "C:\\Program Files (x86)\\git\\bin\\bash.exe"
; shell = "C:\\WINDOWS\\system32\\cmd.exe" (overridden)

One day, perhaps, a new version of npm will pay attention to the overridden shell parameter.

You can also use cross-platform powershell https://github.com/powershell/powershell#get-powershell for npm scripts.

To set for single project, run this from project root folder:

npm config set script-shell pwsh --userconfig ./.npmrc

To globally set for all node projects:

npm config set script-shell pwsh [--global]

just using CMD's way to run .bat!

"scripts": {
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject",
    "app": "cd build & browser-sync start --server --files 'index.html'",
    "bat": "start start-browser.bat",
    "starts": "start http://localhost:7777/datas/ && start http://localhost:7777/Info/"
},

start http://localhost:7777/datas/ && start http://localhost:7777/Info/

Use a specifically created node_module for this purpose. I suggest using npm-run-all, but others exists, such as parallelshell.

Parallelshell example is below for drop-in-replacement for your question.

"scripts": {
    "parallelexample1": "parallelshell \"echo 1\" \"echo 2\" \"echo 3\""
},

following command:

npm run parallelexample1

works both on windows and unix(Linux/MacOS).

Interestingly npm-run-all does not support shell commands; therefore we need to put all shell commands to separate scripts like below.

"scripts": {
   "parallelexample2": "npm-run-all echo*",
    "echo1": "echo 1",
    "echo2": "echo 2",
    "echo3": "echo 3"
},

Following command:

npm run parallelexample2

works both on windows and unix(Linux/MacOS).

In my case I just needed to run npm start from inside Bash. I run cmd then I open bash by running "c:\Program Files\Git\bin\bash.exe". Under bash shell I then was able to call npm build and npm start succesfully.

You may already have bash if you are using Git. If not, you can install it.

Hope this may save someone's time.