doc: improve child_process.markdown copy

[jasnell]

General improvements to child_process.markdown

[cjihrig]

Maybe replace "created" with "spawned" here.

[sam-github]

They are only established when spawn is called with pipe as an option, or fork with silent: true. Unless I misunderstand the diff, this statement seems much more sweeping than is accurate.

[jasnell]

I will clarify that this is the default behavior

[cjihrig]

Left a bunch of comments, but generally LGTM

[sam-github]

... "returning the stdout and stderr when the command completes". <--- that last is the very important distinction between the exec* and the spawn/fork.

[sam-github]

(which is what child_process.exec() does). <-- worth mentioning? to demystify?

[sam-github]

@jasnell Looks like you addressed all my comments, I remembered a couple other useful tidbits of info, though.

[jasnell]

@sam-github ... ok, pushed another set of edits.

[jasnell]

@nodejs/collaborators ... can I ask for some additional review and sign off on this? Thank you!

[cjihrig]

LGTM

[ryansobol]

Does it make sense to list the Sync versions right below their asynchronous counterpart?

[jasnell]

I'd prefer to keep them grouped by async vs sync

[jasnell]

Landed in 7d5c1b5. Can make additional improvements if necessary in a separate PR

[ryansobol]

Sadly, this code example doesn't work even on Unix-like platforms. Since there's no shell wrapper,

1. file must be an absolute path to executable.
2. args must contain all the command line arguments for file.
3. All paths within args must be absolute as well.
4. Stdio redirection is not possible.

Here's an alternative I whipped up that should work on all Unix-like platforms. As always, feel free to use none, some, or all of it.

const execFile = require('child_process').execFile;
const child = execFile('/bin/cat', ['/etc/paths'], (error, stdout, stderr) => {
  if (error) {
    throw error;
  }
  console.log(stdout);
});

[jasnell]

@ryansobol ... can I ask you for a quick PR to update the example? :-) Thank you!

[ryansobol]

@jasnell No problem. See #4504

[MylesBorins]

@jasnell this is not merging cleanly, can you backport this please.

[jasnell]

@thealphanerd ..yes, I'll work on backporting all of these kind of doc changes. They may not all make it into v4.2.5 but I'll work on them

[jasnell]

@thealphanerd ... I'll be working on porting this to LTS early next week.