exec('nohup node some.js &')

Not sure if its a bug rather question.

• node - 5.10.0
• shelljs - ^0.6.0
• os - OS X 10.11.4

---

Can I do something like:

// index.js
require('shelljs/global');
const path = require('path');
const target = path.join(process.cwd(), process.argv[2])
exec('nohup node ./watcher.js ' + target + '&');

// watcher.js
const fs = require('fs');

function watch(dir) {
  fs.watch(dir, (event, filename) => {
    if (filename) {
      // do something
    }
  });
}

watch(process.argv[2]);

node src/index.js ./test/fixtures

---

I expect the index.js to terminate and on ps -ef | grep watcher to find the process corresponding to watcher.js listed

In practice it doesn’t. Is it by design?

[nfischer]

@kevin-smets thanks for following up on this issue.

However, this is not a ShellJS bug. child_process.execSync() and child_process.exec() both have the same issue, so there’s nothing we can do here (our .exec() is built upon those).

For this specific example, here’s some thoughts:

• Use child_process.fork() instead. This is much safer and more robust for executing other scripts asynchronously
  • This is cross-platform. The example above is unix-only (depends on nohup and &)
  • This works even if your version of node is installed under a different name (e.g. nodejs on Ubuntu)
  • You’re safe from shell expansions you might not expect and other security risks
• Why do you really want to start a process without waiting for it to finish?
  • If you really want to start a job and continue using your shell, why not invoke it yourself with a & on the end?
  • If you want your program to start a job in the background while it runs, async (like .fork() above) should be sufficient
  • When your program has finished doing useful work, it can clean up responsibly and kill the child process with .kill(). Otherwise, you’ve got processes running around on their own on your system (yikes!)

[mncharity]

Another option is:

const { spawn } = require('child_process')
spawn( command, args, { detached:true, stdio:'ignore' }).unref()

Or stdio:'inherit', for terminal io.