OS

The os module provides a number of operating system-related utility methods. It can be accessed using:

var os = require('os');

os.freemem()

• Returns {Number}

The os.freemem() method returns the amount of free system memory in bytes as an integer.

os.totalmem()

• Returns {Number}

The os.totalmem() method returns the amount of total system memory in bytes as an integer.

os.hostname()

• Returns {String}

The os.hostname() method returns the hostname of the operating system as a string.

os.networkInterfaces()

• Returns {Object}

The os.networkInterfaces() method returns an object containing only network interfaces that have been assigned a network address.

Each key on the returned object identifies a network interface. The associated value is an array of objects that each describe an assigned network address.

The properties available on the assigned network address object include:

• address {String} The assigned IPv4 or IPv6 address
• netmask {String} The IPv4 or IPv6 network mask
• family {String} Either IPv4 or IPv6
• broadcast {String} The IPv4 broadcast address
• mac {String} The MAC address of the network interface
• internal {Boolean} true if the network interface is a loopback or similar interface that is not remotely accessible; otherwise false
• scopeid {Number} The numeric IPv6 scope ID (only specified when family is IPv6)
• cidr {String} The assigned IPv4 or IPv6 address with the routing prefix in CIDR notation. If the netmask is invalid, this property is set to null

{
  lo: [
    {
      address: '127.0.0.1',
      netmask: '255.0.0.0',
      family: 'IPv4',
      broadcast: '127.0.0.1',
      mac: '00:00:00:00:00:00',
      internal: true,
      cidr: '127.0.0.1/8'
    },
    {
      address: '::1',
      netmask: 'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff',
      family: 'IPv6',
      broadcast: '00:00:00:00:00:00',
      mac: '00:00:00:00:00:00',
      internal: true,
      cidr: '::1/128'
    }
  ],
  eth0: [
    {
      address: '192.168.1.108',
      netmask: '255.255.255.0',
      family: 'IPv4',
      broadcast: '192.168.1.0',
      mac: '01:02:03:0a:0b:0c',
      internal: false,
      cidr: '192.168.1.108/24'
    },
    {
      address: 'fe80::a00:27ff:fe4e:66a1',
      netmask: 'ffff:ffff:ffff:ffff::',
      family: 'IPv6',
      broadcast: '00:00:00:00:00:00',
      mac: '01:02:03:0a:0b:0c',
      internal: false,
      cidr: 'fe80::a00:27ff:fe4e:66a1/64'
    }
  ]
}

os.getPriority([pid])

• pid {integer} The process ID to retrieve scheduling priority for. Default 0.
• Returns: {integer}

The os.getPriority() method returns the scheduling priority for the process specified by pid. If pid is not provided, or is 0, the priority of the current process is returned.

os.setPriority([pid, ]priority)

• pid {integer} The process ID to set scheduling priority for. Default 0.
• priority {integer} The scheduling priority to assign to the process.

The os.setPriority() method attempts to set the scheduling priority for the process specified by pid. If pid is not provided, or is 0, the priority of the current process is used.

The priority input must be an integer between -20 (high priority) and 19 (low priority).