stdio
A sparse array of pipes to the child process, corresponding with positions in the stdio
option passed to {@link spawn} that have been set to the value 'pipe'
. subprocess.stdio[0]
, subprocess.stdio[1]
, and subprocess.stdio[2]
are also available as subprocess.stdin
, 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 subprocess.stdio[1]
is a stream, all other values in the array are null
.
const assert = require('node:assert');
const fs = require('node:fs');
const child_process = require('node:child_process');
const subprocess = child_process.spawn('ls', {
stdio: [
0, // Use parent's stdin for child.
'pipe', // Pipe child's stdout to parent.
fs.openSync('err.out', 'w'), // Direct child's stderr to a file.
],
});
assert.strictEqual(subprocess.stdio[0], null);
assert.strictEqual(subprocess.stdio[0], subprocess.stdin);
assert(subprocess.stdout);
assert.strictEqual(subprocess.stdio[1], subprocess.stdout);
assert.strictEqual(subprocess.stdio[2], null);
assert.strictEqual(subprocess.stdio[2], subprocess.stderr);
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The subprocess.stdio
property can be undefined
if the child process could not be successfully spawned.
Since
v0.7.10