os

The os module provides Node.js-compatible operating system information APIs for JSH applications.

arch()

Returns CPU architecture.

Syntax

arch()

Usage example

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const os = require('os');
console.println(os.arch());

platform()

Returns platform name such as darwin, linux, or windows.

Syntax

platform()

Usage example

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const os = require('os');
console.println(os.platform());

type()

Returns OS type such as Darwin, Linux, or Windows_NT.

Syntax

type()

Usage example

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const os = require('os');
console.println(os.type());

release()

Returns kernel release/version string.

Syntax

release()

Usage example

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const os = require('os');
console.println(os.release());

hostname()

Returns host name.

Syntax

hostname()

Usage example

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const os = require('os');
console.println(os.hostname());

homedir()

Returns current user home directory.

Syntax

homedir()

Usage example

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const os = require('os');
console.println(os.homedir());

tmpdir()

Returns the default temporary directory path.

Syntax

tmpdir()

Usage example

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const os = require('os');
console.println(os.tmpdir());

endianness()

Returns CPU endianness: BE or LE.

Syntax

endianness()

Usage example

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const os = require('os');
console.println(os.endianness());

EOL

Platform-specific end-of-line marker.

• POSIX: \n
• Windows: \r\n

Usage example

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const os = require('os');
console.println(JSON.stringify(os.EOL));

totalmem(), freemem()

Returns total/free memory in bytes.

Syntax

totalmem()
freemem()

Usage example

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const os = require('os');
console.println('total:', os.totalmem());
console.println('free :', os.freemem());

uptime()

Returns system uptime in seconds.

Syntax

uptime()

Usage example

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const os = require('os');
console.println(os.uptime() >= 0);

bootTime()

Returns system boot time as Unix timestamp.

Syntax

bootTime()

Usage example

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const os = require('os');
console.println(os.bootTime() > 0);

loadavg()

Returns load averages as [1min, 5min, 15min].

Syntax

loadavg()

Usage example

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const os = require('os');
const avg = os.loadavg();
console.println(Array.isArray(avg), avg.length);

cpus()

Returns per-CPU information array.

Each item includes fields like:

• model, speed, cores
• vendor, family, model, stepping
• times.user, times.nice, times.sys, times.idle, times.irq (milliseconds)

Syntax

cpus()

Usage example

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const os = require('os');
const list = os.cpus();
console.println(Array.isArray(list), list.length > 0);

cpuCounts()

Returns CPU count.

• true: logical CPU count
• false: physical CPU count

Syntax

cpuCounts(logical)

Usage example

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const os = require('os');
console.println(os.cpuCounts(true));
console.println(os.cpuCounts(false));

cpuPercent()

Returns CPU usage percentages.

• intervalSec: sampling interval in seconds (0 for immediate)
• perCPU: return per-core values when true

Syntax

cpuPercent(intervalSec, perCPU)

Usage example

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const os = require('os');
console.println(Array.isArray(os.cpuPercent(0, true)));

networkInterfaces()

Returns network interface information object.

The object shape is:

• key: interface name
• value: array of address objects
  • address
  • family (IPv4/IPv6)
  • internal (boolean)

Syntax

networkInterfaces()

Usage example

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const os = require('os');
const ifaces = os.networkInterfaces();
console.println(typeof ifaces);

hostInfo()

Returns host information object.

Common fields include:

• hostname, uptime, bootTime, procs
• os, platform, platformFamily, platformVersion
• kernelVersion, kernelArch
• virtualizationSystem, virtualizationRole, hostId

Syntax

hostInfo()

Usage example

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const os = require('os');
const info = os.hostInfo();
console.println(typeof info.hostname, typeof info.uptime);

userInfo()

Returns current user information.

Returned fields include:

• username, homedir, shell
• uid, gid

Syntax

userInfo([options])

Usage example

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const os = require('os');
const user = os.userInfo();
console.println(user.username, user.homedir);

diskPartitions()

Returns disk partition list.

Syntax

diskPartitions([all])

Usage example

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const os = require('os');
const parts = os.diskPartitions();
console.println(Array.isArray(parts), parts.length >= 0);

diskUsage()

Returns disk usage for the given path.

Typical fields include total, used, free, usedPercent.

Syntax

diskUsage(path)

Usage example

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const os = require('os');
const usage = os.diskUsage('.');
console.println(typeof usage.total, typeof usage.usedPercent);

diskIOCounters()

Returns disk I/O counters.

• names omitted or empty: all devices
• names specified: selected devices

Syntax

diskIOCounters([names])

Usage example

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const os = require('os');
const counters = os.diskIOCounters();
console.println(typeof counters);

netProtoCounters()

Returns network protocol counters.

Syntax

netProtoCounters([proto])

Usage example

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const os = require('os');
const counters = os.netProtoCounters();
console.println(typeof counters);

constants

An object that contains operating system related constants.

It currently provides the following child objects.

• os.constants.signals
• os.constants.priority

Usage example

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const os = require('os');

console.println(typeof os.constants.signals.SIGINT);
console.println(typeof os.constants.priority.PRIORITY_NORMAL);

os.constants.signals

An object that provides signal names and their numeric values.

These constants use canonical Unix-style signal numbers for API compatibility. On Windows, not every numeric value maps to a distinct native signal behavior.

For example, it includes entries such as:

These values can be passed to process.kill() as numeric signals.

On Windows, SIGINT is treated specially. JSH attempts to deliver it as an interrupt-style console control event, which is the closest available equivalent. By contrast, SIGTERM, SIGQUIT, and SIGKILL behave as termination requests on Windows.

Usage example

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const os = require('os');
const process = require('process');

process.kill(12345, os.constants.signals.SIGTERM);

Relationship With The process Signal API

os.constants.signals provides signal numbers, while the actual signal handling and delivery are performed by the process module.

• receive a signal: process.on('SIGINT', handler)
• send a signal: process.kill(pid, os.constants.signals.SIGTERM)

process.on() accepts case-insensitive signal names, but signal event names must still use the canonical SIG-prefixed form such as SIGINT or sigint. Bare aliases such as term are not signal listener names.

process.kill() is more permissive and accepts aliases such as term in addition to canonical names. By contrast, os.constants.signals exposes canonical constant names only.

On Windows, process.kill(pid, os.constants.signals.SIGINT) is best-effort and depends on Windows console routing rules.

Usage example

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const os = require('os');
const process = require('process');

process.on('sigint', () => {
  console.println('caught');
});

process.kill(process.pid, os.constants.signals.SIGINT);

os.constants.priority

An object that defines process priority levels.

Main fields

Usage example

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const os = require('os');
console.println(os.constants.priority.PRIORITY_NORMAL);
console.println(os.constants.priority.PRIORITY_HIGH);