Install dependencies using lerna fails

I am trying to add a module as dev-dependency from npm to one of several modules I have in my lerna repo, but when doing that neither is the module added to only one of my modules, nor is it added as a dev-dependency. Instead it is added to all of my local modules and it also is added as a normal dependency.

I have created the following:

mkdir FirstProject
cd FirstProject
yarn init
yarn add lerna --dev
npm run env lerna init
mkdir packages/one
mkdir packages/two
cd packages/one
yarn init
cd ../..
cd packages/two
yarn init
cd ../..

I now have the following tree structure:

myuser@mylaptop:~/FirstProject$ tree -I node_modules
.
├── lerna.json
├── package.json
├── packages
│   ├── one
│   │   └── package.json
│   └── two
│       └── package.json
└── yarn.lock

Both, packages/one/package.json and packages/two/package.json look alike (except the name field):

{
  "name": "one",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT"
}

If I now try to install a new devDependency in packages/one, i.e. angular, I could cd packages/one and then yarn add angular --dev.

But as suggested in the lerna documentation there is a lerna add command that is supposed to do exactly that. The command to do exactly the above is supposed to be the following:

npm run env lerna add angular --scope=one --dev

But, now both packages/one/package.json and packages/two/package.json look again alike (except the name field) and the entry was made as a dependency and not as a devDependency:

{
  "name": "one",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "dependencies": {
    "angular": "^1.6.10"
  }
}

Is this a bug or am I doing something wrong?

EDIT:

Just in case this matters:

lerna version 2.11.0
npm version 5.8.0
yarn version 1.6.0
node version v9.11.1
Work environment Ubuntu 16.04

Solution

You forgot to mention the missing last step of lerna init to create lerna.json :-)

Anyhow, try with npm>5.2:

npx lerna add angular --scope=one --dev

npx --help: Execute binaries from npm packages.

or the manual execution of the binary:

./node_modules/.bin/lerna add angular --scope=one --dev

And I do have the resulting:

{
  "name": "one",
  "version": "1.0.0",
  "main": "index.js",
  "license": "MIT",
  "devDependencies": {
    "angular": "^1.6.10"
  }
}