Killing a node process using a package.json stop script

Question

I am trying to write a stop command for my nodeJS application which greps for a node process and kills it, so far I have:

{
  ...
  "scripts": {
    "start": "node src/main/webapp/index.js",
    "stop": "kill \"$(ps ux | grep node | grep -Eo '^\\s+[0-9]+' | tr -d '[[:space:]]')\""
  }
  ...
}

If I run ps ux I get

  PID    PPID    PGID     WINPID   TTY         UID    STIME COMMAND
12228    8428   12228      12960  cons0     197608 22:02:12 /usr/bin/ps
 4840       1    4840       4840  cons0     197608 22:01:46 /usr/bin/bash
13484   12292   12292       8024  cons0     197608 22:02:07 /c/Program Files/nodejs/node

If I run echo "$(ps ux | grep node | grep -Eo '^\s+[0-9]+' | tr -d '[[:space:]]')" then I get output 13484 so I know that bit works. However when I run npm stop I get the error:

npm ERR! Windows_NT 6.3.9600
npm ERR! argv "C:\\Program Files\\nodejs\\node.exe" "C:\\Program Files\\nodejs\\node_modules\\npm\\bin\\npm-cli.js" "stop"
npm ERR! node v0.12.4
npm ERR! npm  v2.10.1
npm ERR! code ELIFECYCLE
npm ERR! [email protected] stop: `kill "$(ps ux | grep node | grep -Eo '^\s+[0-9]+' | tr -d '[[:space:]]')"`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the [email protected] stop script 'kill "$(ps ux | grep node | grep -Eo '^\s+[0-9]+' | tr -d '[[:space:]]')"'.
npm ERR! This is most likely a problem with the app package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     kill "$(ps ux | grep node | grep -Eo '^\s+[0-9]+' | tr -d '[[:space:]]')"
npm ERR! You can get their info via:
npm ERR!     npm owner ls app
npm ERR! There is likely additional logging output above.

Why is this breaking? Is there an easier way to do this?

Answer 1

This seems to work:

"scripts": {
  "start": "node src/main/webapp/index.js & echo $! > .pid",
  "stop": "kill $(cat .pid)"
}

Maybe this is good enough for what you are trying to achieve but I guess there are better ways.