doc: fix copy node executable in Windows

[yoavain]

Bug description

The Windows where command looks for a pattern in the %Path% and lists all matches.
The first match is the one that gets executed when called.
The problem with the current code is that if where finds more than one match, the for loop will copy each of them.
The result will be having the last match instead of the first one.

I encountered this when I tried to create a single executable application via GitHub Actions.
I was using a simple action configuration file:

name: Node CI

jobs:
  build:

    runs-on: windows-latest

    strategy:
      matrix:
        node-version: [20.x]

    steps:
    - name: Setup NodeJS
      uses: actions/setup-node@v3.6.0
      with:
        node-version: ${{ matrix.node-version }}
        cache: npm

But still, after copying the node executable using

for /F "tokens=*" %n IN ('where.exe node') DO @(copy "%n" hello.exe)

Log showed:

1 file(s) copied.
1 file(s) copied.

And running

hello.exe -v

Got:

v18.16.0

Fix description

node -e "require('fs').copyFileSync(process.execPath, 'hello.exe')"

Explanation:

1. process.execPath gives the absolute pathname of the executable that started the Node.js process
2. node -e evaluates the content inside the quotations
3. require('fs') loads the fs module
4. copyFileSync does the file copy

This solution should be valid for any other OS.
However, tested it on Windows only.

[nodejs-github-bot]

Review requested:

• @nodejs/single-executable

[RaisinTen]

Nice catch, thanks! Might make the docs simpler if we used the same command for both powershell and cmd. We could use the same thing for non-Windows too if we remove the .exe part.

[yoavain]

Right, the same command can apply to both powershell and cmd.
Regarding non-windows, I can't decide what is a more "elegant" command...
WDYT?

[RaisinTen]

I'm personally okay with both. Does anyone else have a preference? If not, I think it's fine to only update the Windows commands and unify both the cmd and powershell parts into the one you suggested.

[RaisinTen]

LGTM

[nodejs-github-bot]

Landed in d9438cc

[ruyadorno]

This commit does not land cleanly on v18.x-staging and will need manual backport in case we want it in v18.