doc: change `child` to `subprocess`

PR-URL: https://github.com/nodejs/node/pull/14578
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>

doc/api/child_process.md

@@ -333,7 +333,7 @@ The `child_process.fork()` method is a special case of
 Like [`child_process.spawn()`][], a [`ChildProcess`][] object is returned. The returned
 [`ChildProcess`][] will have an additional communication channel built-in that
 allows messages to be passed back and forth between the parent and child. See
-[`child.send()`][] for details.
+[`subprocess.send()`][] for details.
 
 It is important to keep in mind that spawned Node.js child processes are
 independent of the parent with exception of the IPC communication channel
@@ -472,10 +472,10 @@ Example of checking for failed `spawn`:
 
 ```js
 const { spawn } = require('child_process');
-const child = spawn('bad_command');
+const subprocess = spawn('bad_command');
 
-child.on('error', (err) => {
+subprocess.on('error', (err) => {
-  console.log('Failed to start child process.');
+  console.log('Failed to start subprocess.');
 });
 ```
 
@@ -503,10 +503,10 @@ child processes may continue running after the parent exits regardless of
 whether they are detached or not.  See setsid(2) for more information.
 
 By default, the parent will wait for the detached child to exit. To prevent
-the parent from waiting for a given `child`, use the `child.unref()` method.
+the parent from waiting for a given `subprocess`, use the `subprocess.unref()`
-Doing so will cause the parent's event loop to not include the child in its
+method. Doing so will cause the parent's event loop to not include the child in
-reference count, allowing the parent to exit independently of the child, unless
+its reference count, allowing the parent to exit independently of the child,
-there is an established IPC channel between the child and parent.
+unless there is an established IPC channel between the child and parent.
 
 When using the `detached` option to start a long-running process, the process
 will not stay running in the background after the parent exits unless it is
@@ -520,12 +520,12 @@ Example of a long-running process, by detaching and also ignoring its parent
 ```js
 const { spawn } = require('child_process');
 
-const child = spawn(process.argv[0], ['child_program.js'], {
+const subprocess = spawn(process.argv[0], ['child_program.js'], {
   detached: true,
   stdio: 'ignore'
 });
 
-child.unref();
+subprocess.unref();
 ```
 
 Alternatively one can redirect the child process' output into files:
@@ -536,12 +536,12 @@ const { spawn } = require('child_process');
 const out = fs.openSync('./out.log', 'a');
 const err = fs.openSync('./out.log', 'a');
 
-const child = spawn('prg', [], {
+const subprocess = spawn('prg', [], {
   detached: true,
   stdio: [ 'ignore', out, err ]
 });
 
-child.unref();
+subprocess.unref();
 ```
 
 #### options.stdio
@@ -555,9 +555,10 @@ changes:
 
 The `options.stdio` option is used to configure the pipes that are established
 between the parent and child process. By default, the child's stdin, stdout,
-and stderr are redirected to corresponding [`child.stdin`][], [`child.stdout`][], and
+and stderr are redirected to corresponding [`subprocess.stdin`][],
-[`child.stderr`][] streams on the [`ChildProcess`][] object. This is equivalent to
+[`subprocess.stdout`][], and [`subprocess.stderr`][] streams on the
-setting the `options.stdio` equal to `['pipe', 'pipe', 'pipe']`.
+[`ChildProcess`][] object. This is equivalent to setting the `options.stdio`
+equal to `['pipe', 'pipe', 'pipe']`.
 
 For convenience, `options.stdio` may be one of the following strings:
 
@@ -573,17 +574,18 @@ pipes between the parent and child. The value is one of the following:
 
 1. `'pipe'` - Create a pipe between the child process and the parent process.
    The parent end of the pipe is exposed to the parent as a property on the
-   `child_process` object as [`child.stdio[fd]`][`stdio`]. Pipes created for
+   `child_process` object as [`subprocess.stdio[fd]`][`stdio`]. Pipes created
-   fds 0 - 2 are also available as [`child.stdin`][], [`child.stdout`][]
+   for fds 0 - 2 are also available as [`subprocess.stdin`][],
-   and [`child.stderr`][], respectively.
+   [`subprocess.stdout`][] and [`subprocess.stderr`][], respectively.
 2. `'ipc'` - Create an IPC channel for passing messages/file descriptors
    between parent and child. A [`ChildProcess`][] may have at most *one* IPC stdio
-   file descriptor. Setting this option enables the [`child.send()`][] method.
+   file descriptor. Setting this option enables the [`subprocess.send()`][]
-   If the child writes JSON messages to this file descriptor, the
+   method. If the child writes JSON messages to this file descriptor, the
-   [`child.on('message')`][`'message'`] event handler will be triggered in the parent.
+   [`subprocess.on('message')`][`'message'`] event handler will be triggered in
-   If the child is a Node.js process, the presence of an IPC channel will enable
+   the parent. If the child is a Node.js process, the presence of an IPC channel
-   [`process.send()`][], [`process.disconnect()`][], [`process.on('disconnect')`][], and
+   will enable [`process.send()`][], [`process.disconnect()`][],
-   [`process.on('message')`] within the child.
+   [`process.on('disconnect')`][], and [`process.on('message')`] within the
+   child.
 3. `'ignore'` - Instructs Node.js to ignore the fd in the child. While Node.js
    will always open fds 0 - 2 for the processes it spawns, setting the fd to
    `'ignore'` will cause Node.js to open `/dev/null` and attach it to the
@@ -828,9 +830,10 @@ added: v0.7.2
 -->
 
 The `'disconnect'` event is emitted after calling the
-[`child.disconnect()`][] method in parent process or [`process.disconnect()`][] in child process. After
+[`subprocess.disconnect()`][] method in parent process or
-disconnecting it is no longer possible to send or receive messages, and the
+[`process.disconnect()`][] in child process. After disconnecting it is no longer
-[`child.connected`][] property is `false`.
+possible to send or receive messages, and the [`subprocess.connected`][]
+property is `false`.
 
 ### Event: 'error'
 
@@ -846,7 +849,7 @@ The `'error'` event is emitted whenever:
 When listening to both the `'exit'` and `'error'` events, it is important
 to guard against accidentally invoking handler functions multiple times.
 
-See also [`child.kill()`][] and [`child.send()`][].
+See also [`subprocess.kill()`][] and [`subprocess.send()`][].
 
 ### Event: 'exit'
 <!-- YAML
@@ -883,56 +886,56 @@ added: v0.5.9
 The `'message'` event is triggered when a child process uses [`process.send()`][]
 to send messages.
 
-### child.channel
+### subprocess.channel
 <!-- YAML
 added: v7.1.0
 -->
 
 * {Object} A pipe representing the IPC channel to the child process.
 
-The `child.channel` property is a reference to the child's IPC channel. If no
+The `subprocess.channel` property is a reference to the child's IPC channel. If
-IPC channel currently exists, this property is `undefined`.
+no IPC channel currently exists, this property is `undefined`.
 
-### child.connected
+### subprocess.connected
 <!-- YAML
 added: v0.7.2
 -->
 
-* {boolean} Set to `false` after `child.disconnect()` is called
+* {boolean} Set to `false` after `subprocess.disconnect()` is called
 
-The `child.connected` property indicates whether it is still possible to send
+The `subprocess.connected` property indicates whether it is still possible to
-and receive messages from a child process. When `child.connected` is `false`, it
+send and receive messages from a child process. When `subprocess.connected` is
-is no longer possible to send or receive messages.
+`false`, it is no longer possible to send or receive messages.
 
-### child.disconnect()
+### subprocess.disconnect()
 <!-- YAML
 added: v0.7.2
 -->
 
 Closes the IPC channel between parent and child, allowing the child to exit
 gracefully once there are no other connections keeping it alive. After calling
-this method the `child.connected` and `process.connected` properties in both
+this method the `subprocess.connected` and `process.connected` properties in
-the parent and child (respectively) will be set to `false`, and it will be no
+both the parent and child (respectively) will be set to `false`, and it will be
-longer possible to pass messages between the processes.
+no longer possible to pass messages between the processes.
 
 The `'disconnect'` event will be emitted when there are no messages in the
 process of being received. This will most often be triggered immediately after
-calling `child.disconnect()`.
+calling `subprocess.disconnect()`.
 
 Note that when the child process is a Node.js instance (e.g. spawned using
 [`child_process.fork()`]), the `process.disconnect()` method can be invoked
 within the child process to close the IPC channel as well.
 
-### child.kill([signal])
+### subprocess.kill([signal])
 <!-- YAML
 added: v0.1.90
 -->
 
 * `signal` {string}
 
-The `child.kill()` methods sends a signal to the child process. If no argument
+The `subprocess.kill()` methods sends a signal to the child process. If no
-is given, the process will be sent the `'SIGTERM'` signal. See signal(7) for
+argument is given, the process will be sent the `'SIGTERM'` signal. See
-a list of available signals.
+signal(7) for a list of available signals.
 
 ```js
 const { spawn } = require('child_process');
@@ -967,7 +970,7 @@ as in this example:
 'use strict';
 const { spawn } = require('child_process');
 
-const child = spawn(
+const subprocess = spawn(
   'sh',
   [
     '-c',
@@ -980,11 +983,11 @@ const child = spawn(
 );
 
 setTimeout(() => {
-  child.kill(); // does not terminate the node process in the shell
+  subprocess.kill(); // does not terminate the node process in the shell
 }, 2000);
 ```
 
-### child.pid
+### subprocess.pid
 <!-- YAML
 added: v0.1.90
 -->
@@ -1003,7 +1006,7 @@ console.log(`Spawned child pid: ${grep.pid}`);
 grep.stdin.end();
 ```
 
-### child.send(message[, sendHandle[, options]][, callback])
+### subprocess.send(message[, sendHandle[, options]][, callback])
 <!-- YAML
 added: v0.5.9
 changes:
@@ -1026,9 +1029,10 @@ changes:
 * Returns: {boolean}
 
 When an IPC channel has been established between the parent and child (
-i.e. when using [`child_process.fork()`][]), the `child.send()` method can be
+i.e. when using [`child_process.fork()`][]), the `subprocess.send()` method can
-used to send messages to the child process. When the child process is a Node.js
+be used to send messages to the child process. When the child process is a
-instance, these messages can be received via the [`process.on('message')`][] event.
+Node.js instance, these messages can be received via the
+[`process.on('message')`][] event.
 
 For example, in the parent script:
 
@@ -1064,8 +1068,8 @@ for use within Node.js core and will not be emitted in the child's
 Applications should avoid using such messages or listening for
 `'internalMessage'` events as it is subject to change without notice.
 
-The optional `sendHandle` argument that may be passed to `child.send()` is for
+The optional `sendHandle` argument that may be passed to `subprocess.send()` is
-passing a TCP server or socket object to the child process. The child will
+for passing a TCP server or socket object to the child process. The child will
 receive the object as the second argument passed to the callback function
 registered on the [`process.on('message')`][] event. Any data that is received
 and buffered in the socket will not be sent to the child.
@@ -1086,7 +1090,7 @@ If no `callback` function is provided and the message cannot be sent, an
 `'error'` event will be emitted by the [`ChildProcess`][] object. This can happen,
 for instance, when the child process has already exited.
 
-`child.send()` will return `false` if the channel has closed or when the
+`subprocess.send()` will return `false` if the channel has closed or when the
 backlog of unsent messages exceeds a threshold that makes it unwise to send
 more. Otherwise, the method returns `true`. The `callback` function can be
 used to implement flow control.
@@ -1097,7 +1101,7 @@ The `sendHandle` argument can be used, for instance, to pass the handle of
 a TCP server object to the child process as illustrated in the example below:
 
 ```js
-const child = require('child_process').fork('child.js');
+const subprocess = require('child_process').fork('subprocess.js');
 
 // Open up the server object and send the handle.
 const server = require('net').createServer();
@@ -1105,7 +1109,7 @@ server.on('connection', (socket) => {
   socket.end('handled by parent');
 });
 server.listen(1337, () => {
-  child.send('server', server);
+  subprocess.send('server', server);
 });
 ```
 
@@ -1137,8 +1141,8 @@ handle connections with "normal" or "special" priority:
 
 ```js
 const { fork } = require('child_process');
-const normal = fork('child.js', ['normal']);
+const normal = fork('subprocess.js', ['normal']);
-const special = fork('child.js', ['special']);
+const special = fork('subprocess.js', ['special']);
 
 // Open up the server and send sockets to child. Use pauseOnConnect to prevent
 // the sockets from being read before they are sent to the child process.
@@ -1156,8 +1160,8 @@ server.on('connection', (socket) => {
 server.listen(1337);
 ```
 
-The `child.js` would receive the socket handle as the second argument passed
+The `subprocess.js` would receive the socket handle as the second argument
-to the event callback function:
+passed to the event callback function:
 
 ```js
 process.on('message', (m, socket) => {
@@ -1184,7 +1188,7 @@ time it takes to send the connection to the child.
 *Note*: This function uses [`JSON.stringify()`][] internally to serialize the
 `message`.
 
-### child.stderr
+### subprocess.stderr
 <!-- YAML
 added: v0.1.90
 -->
@@ -1196,10 +1200,10 @@ A `Readable Stream` that represents the child process's `stderr`.
 If the child was spawned with `stdio[2]` set to anything other than `'pipe'`,
 then this will be `null`.
 
-`child.stderr` is an alias for `child.stdio[2]`. Both properties will refer to
+`subprocess.stderr` is an alias for `subprocess.stdio[2]`. Both properties will
-the same value.
+refer to the same value.
 
-### child.stdin
+### subprocess.stdin
 <!-- YAML
 added: v0.1.90
 -->
@@ -1214,10 +1218,10 @@ continue until this stream has been closed via `end()`.*
 If the child was spawned with `stdio[0]` set to anything other than `'pipe'`,
 then this will be `null`.
 
-`child.stdin` is an alias for `child.stdio[0]`. Both properties will refer to
+`subprocess.stdin` is an alias for `subprocess.stdio[0]`. Both properties will
-the same value.
+refer to the same value.
 
-### child.stdio
+### subprocess.stdio
 <!-- YAML
 added: v0.7.10
 -->
@@ -1226,20 +1230,20 @@ added: v0.7.10
 
 A sparse array of pipes to the child process, corresponding with positions in
 the [`stdio`][] option passed to [`child_process.spawn()`][] that have been set
-to the value `'pipe'`. Note that `child.stdio[0]`, `child.stdio[1]`, and
+to the value `'pipe'`. Note that `subprocess.stdio[0]`, `subprocess.stdio[1]`,
-`child.stdio[2]` are also available as `child.stdin`, `child.stdout`, and
+and `subprocess.stdio[2]` are also available as `subprocess.stdin`,
-`child.stderr`, respectively.
+`subprocess.stdout`, and `subprocess.stderr`, respectively.
 
 In the following example, only the child's fd `1` (stdout) is configured as a
-pipe, so only the parent's `child.stdio[1]` is a stream, all other values in
+pipe, so only the parent's `subprocess.stdio[1]` is a stream, all other values
-the array are `null`.
+in the array are `null`.
 
 ```js
 const assert = require('assert');
 const fs = require('fs');
 const child_process = require('child_process');
 
-const child = child_process.spawn('ls', {
+const subprocess = child_process.spawn('ls', {
   stdio: [
     0, // Use parent's stdin for child
     'pipe', // Pipe child's stdout to parent
@@ -1247,17 +1251,17 @@ const child = child_process.spawn('ls', {
   ]
 });
 
-assert.strictEqual(child.stdio[0], null);
+assert.strictEqual(subprocess.stdio[0], null);
-assert.strictEqual(child.stdio[0], child.stdin);
+assert.strictEqual(subprocess.stdio[0], subprocess.stdin);
 
-assert(child.stdout);
+assert(subprocess.stdout);
-assert.strictEqual(child.stdio[1], child.stdout);
+assert.strictEqual(subprocess.stdio[1], subprocess.stdout);
 
-assert.strictEqual(child.stdio[2], null);
+assert.strictEqual(subprocess.stdio[2], null);
-assert.strictEqual(child.stdio[2], child.stderr);
+assert.strictEqual(subprocess.stdio[2], subprocess.stderr);
 ```
 
-### child.stdout
+### subprocess.stdout
 <!-- YAML
 added: v0.1.90
 -->
@@ -1269,8 +1273,8 @@ A `Readable Stream` that represents the child process's `stdout`.
 If the child was spawned with `stdio[1]` set to anything other than `'pipe'`,
 then this will be `null`.
 
-`child.stdout` is an alias for `child.stdio[1]`. Both properties will refer
+`subprocess.stdout` is an alias for `subprocess.stdio[1]`. Both properties will
-to the same value.
+refer to the same value.
 
 ## `maxBuffer` and Unicode
 
@@ -1300,13 +1304,13 @@ unavailable.
 [`Error`]: errors.html#errors_class_error
 [`EventEmitter`]: events.html#events_class_eventemitter
 [`JSON.stringify()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
-[`child.connected`]: #child_process_child_connected
+[`subprocess.connected`]: #child_process_subprocess_connected
-[`child.disconnect()`]: #child_process_child_disconnect
+[`subprocess.disconnect()`]: #child_process_subprocess_disconnect
-[`child.kill()`]: #child_process_child_kill_signal
+[`subprocess.kill()`]: #child_process_subprocess_kill_signal
-[`child.send()`]: #child_process_child_send_message_sendhandle_options_callback
+[`subprocess.send()`]: #child_process_subprocess_send_message_sendhandle_options_callback
-[`child.stderr`]: #child_process_child_stderr
+[`subprocess.stderr`]: #child_process_subprocess_stderr
-[`child.stdin`]: #child_process_child_stdin
+[`subprocess.stdin`]: #child_process_subprocess_stdin
-[`child.stdout`]: #child_process_child_stdout
+[`subprocess.stdout`]: #child_process_subprocess_stdout
 [`child_process.exec()`]: #child_process_child_process_exec_command_options_callback
 [`child_process.execFile()`]: #child_process_child_process_execfile_file_args_options_callback
 [`child_process.execFileSync()`]: #child_process_child_process_execfilesync_file_args_options

doc/api/errors.md

@@ -692,7 +692,7 @@ platform-dependent.
 ### ERR_INVALID_HANDLE_TYPE
 
 Used when an attempt is made to send an unsupported "handle" over an IPC
-communication channel to a child process. See [`child.send()`] and
+communication channel to a child process. See [`subprocess.send()`] and
 [`process.send()`] for more information.
 
 <a id="ERR_INVALID_HTTP_TOKEN"></a>
@@ -910,7 +910,7 @@ Used when an invalid or unknown encoding option is passed to an API.
 ### ERR_UNKNOWN_SIGNAL
 
 Used when an invalid or unknown process signal is passed to an API expecting a
-valid signal (such as [`child.kill()`][]).
+valid signal (such as [`subprocess.kill()`][]).
 
 <a id="ERR_UNKNOWN_STDIN_TYPE"></a>
 ### ERR_UNKNOWN_STDIN_TYPE
@@ -935,8 +935,8 @@ Used when the V8 BreakIterator API is used but the full ICU data set is not
 installed.
 
 [`ERR_INVALID_ARG_TYPE`]: #ERR_INVALID_ARG_TYPE
-[`child.kill()`]: child_process.html#child_process_child_kill_signal
+[`subprocess.kill()`]: child_process.html#child_process_subprocess_kill_signal
-[`child.send()`]: child_process.html#child_process_child_send_message_sendhandle_options_callback
+[`subprocess.send()`]: child_process.html#child_process_subprocess_send_message_sendhandle_options_callback
 [`fs.readFileSync`]: fs.html#fs_fs_readfilesync_path_options
 [`fs.readdir`]: fs.html#fs_fs_readdir_path_options_callback
 [`fs.unlink`]: fs.html#fs_fs_unlink_path_callback