# OS Stability: 2 - Stable Provides a few basic operating-system related utility functions. Use `require('os')` to access this module. ## os.EOL A constant defining the appropriate End-of-line marker for the operating system. ## os.arch() Returns the operating system CPU architecture. Possible values are `'x64'`, `'arm'` and `'ia32'`. Returns the value of [`process.arch`][]. ## os.cpus() Returns an array of objects containing information about each CPU/core installed: model, speed (in MHz), and times (an object containing the number of milliseconds the CPU/core spent in: user, nice, sys, idle, and irq). Example inspection of os.cpus: ```js [ { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 252020, nice: 0, sys: 30340, idle: 1070356870, irq: 0 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 306960, nice: 0, sys: 26980, idle: 1071569080, irq: 0 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 248450, nice: 0, sys: 21750, idle: 1070919370, irq: 0 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 256880, nice: 0, sys: 19430, idle: 1070905480, irq: 20 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 511580, nice: 20, sys: 40900, idle: 1070842510, irq: 0 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 291660, nice: 0, sys: 34360, idle: 1070888000, irq: 10 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 308260, nice: 0, sys: 55410, idle: 1071129970, irq: 880 } }, { model: 'Intel(R) Core(TM) i7 CPU 860 @ 2.80GHz', speed: 2926, times: { user: 266450, nice: 1480, sys: 34920, idle: 1072572010, irq: 30 } } ] ``` Note that since `nice` values are UNIX centric in Windows the `nice` values of all processors are always 0. ## os.endianness() Returns the endianness of the CPU. Possible values are `'BE'` for big endian or `'LE'` for little endian. ## os.freemem() Returns the amount of free system memory in bytes. ## os.homedir() Returns the home directory of the current user. ## os.hostname() Returns the hostname of the operating system. ## os.loadavg() Returns an array containing the 1, 5, and 15 minute load averages. The load average is a measure of system activity, calculated by the operating system and expressed as a fractional number. 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. ## os.networkInterfaces() Get a list of network interfaces: ```js { lo: [ { address: '127.0.0.1', netmask: '255.0.0.0', family: 'IPv4', mac: '00:00:00:00:00:00', internal: true }, { address: '::1', netmask: 'ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff', family: 'IPv6', mac: '00:00:00:00:00:00', internal: true } ], eth0: [ { address: '192.168.1.108', netmask: '255.255.255.0', family: 'IPv4', mac: '01:02:03:0a:0b:0c', internal: false }, { address: 'fe80::a00:27ff:fe4e:66a1', netmask: 'ffff:ffff:ffff:ffff::', family: 'IPv6', mac: '01:02:03:0a:0b:0c', internal: false } ] } ``` Note that due to the underlying implementation this will only return network interfaces that have been assigned an address. ## os.platform() Returns the operating system platform. Possible values are `'darwin'`, `'freebsd'`, `'linux'`, `'sunos'` or `'win32'`. Returns the value of [`process.platform`][]. ## os.release() Returns the operating system release. ## os.tmpdir() Returns the operating system's default directory for temporary files. ## os.totalmem() Returns the total amount of system memory in bytes. ## os.type() Returns the operating system name. For example `'Linux'` on Linux, `'Darwin'` on OS X and `'Windows_NT'` on Windows. ## os.uptime() Returns the system uptime in seconds. ## os.userInfo([options]) * `options` {Object} * `encoding` {String} Character encoding used to interpret resulting strings. If `encoding` is set to `'buffer'`, the `username`, `shell`, and `homedir` values will be `Buffer` instances. (Default: 'utf8') Returns a subset of the password file entry for the current effective user. The returned object includes the `username`, `uid`, `gid`, `shell`, and `homedir`. On Windows, the `uid` and `gid` fields are `-1`, and `shell` is `null`. The value of `homedir` returned by `userInfo()` comes directly from the operating system. This differs from the result of `os.homedir()`, which queries several environment variables for the home directory before falling back to the operating system response. [`process.arch`]: process.html#process_process_arch [`process.platform`]: process.html#process_process_platform