Node.js : OS Module

Introduction

The node.js "os" module provides a few basic operating-system related utility functions. To access these functions use require('os'). Following functions are in the module 'os'.

os.tmpdir()

The function is used to get the operating system's default directory for temp files.

Example :

C:\Users\workarea>node
> os.tmpdir()
'C:\\Users\\workarea\\AppData\\Local\\Temp'

os.endianness()

The function is used to get the endianness of the CPU. Possible values are "BE" or "LE".+

Note : According to Wikipedia the terms endian and endianness refer to the convention used to interpret the bytes making up a data word when those bytes are stored in computer memory.

Example :

> os.endianness()
'LE'
>

os.hostname()

The function is used to get the hostname of the operating system.

Example :

> os.hostname()
'workarea-PC'
>

os.type()

The function is used to get the operating system name.

Example :

> os.type()
'Windows_NT'
>

os.platform()

The function is used to get the operating system platform.

Examples :

> os.platform()
'win32'

os.arch()

The function is used to get the operating system CPU architecture.

Example :

> os.arch() 
'ia32'

os.release()

The function returns the operating system release.

Example :

> os.release()
'6.1.7600'

os.uptime()

The function returns the system uptime in seconds.

Example :

> os.uptime()
20218.5031917

os.loadavg()

The function returns an array containing the 1, 5, and 15 minute load averages.

• As a rule of thumb, the load average should ideally be less than the number of logical CPUs in the system.
• The load average is a very UNIX-y concept.
• There is no real equivalent on Windows platforms. That is why this function always returns [0, 0, 0] on Windows.

Example (Windows) :

> os.loadavg() 
[ 0, 0, 0 ]

Example (Ubuntu LTS 14.04 (Kernel version 3.13.0-24-generic) :

> os.loadavg()
[ 3.06396484375, 1.7939453125, 0.7080078125 ]

os.totalmem()

The function is used to get the total amount of system memory in bytes.

Example :

> os.totalmem() 
3210207232

os.freemem()

The function is used to get the amount of free system memory in bytes.

Example :

> os.freemem() 
1521180672

os.cpus()

The function returns an array of objects containing information about each CPU/core installed: model, speed (in MHz), and times.

Note : An object containing the number of milliseconds the CPU/core spent in: user, nice, sys, idle, and irq.

Examples :

> os.cpus()
[ { model: 'Pentium(R) Dual-Core  CPU      E5200  @ 2.50GHz',
    speed: 2500,
    times:
       { user: 2630130,
	     nice: 0,
		 sys: 1139743,
		 idle: 19108656,
		 irq: 19952 } },
   { model: 'Pentium(R) Dual-Core  CPU      E5200  @ 2.50GHz',
         speed: 2500,
		 times:
	   { user: 2803618,
	     nice: 0,
		 sys: 1047515,
         idle: 19025788,
		 irq: 25459 } } ]

os.networkInterfaces()

The function is used to get the list of network interfaces.

Example :

> os.networkInterfaces()
{ 'Local Area Connection 5':
   [ { address: 'fe80::e159:a5d6:ce2a:90b6',
       family: 'IPv6',
	   internal: false },
	 { address: '192.168.0.100',
	   family: 'IPv4',
	   internal: false } ],
  'Loopback Pseudo-Interface 1':
    [ { address: '::1',
	    family: 'IPv6',
		internal: true },
      { address: '127.0.0.1',
	   family: 'IPv4',
	   internal: true } ],
  'Teredo Tunneling Pseudo-Interface':
    [ { address: '2001:0:9d38:6abd:281a:2050:3f57:ff9b',
	    family: 'IPv6',
		internal: false },
      { address: 'fe80::281a:2050:3f57:ff9b',
	    family: 'IPv6',
		internal: false } ] }

os.EOL

A constant defining the appropriate End-of-line marker for the operating system.

Example :

gt; os.EOL
'\r\n'

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