OS
目录
- os.EOL
- os.arch()
- os.constants
- os.cpus()
- os.devNull
- os.endianness()
- os.freemem()
- os.getPriority([pid])
- os.homedir()
- os.hostname()
- os.loadavg()
- os.networkInterfaces()
- os.platform()
- os.release()
- os.setPriority([pid, ]priority)
- os.tmpdir()
- os.totalmem()
- os.type()
- os.uptime()
- os.userInfo([options])
- os.version()
- os.machine()
- OS constants
Added in: v0.10.0
源代码: lib/os.js
The node:os module provides operating system-related utility methods and
properties. It can be accessed using:
JS
M os.EOL
Added in: v0.7.8
The operating system-specific end-of-line marker.
\non POSIX\r\non Windows
M os.arch()
Added in: v0.5.0
- Returns:
string
Returns the operating system CPU architecture for which the Node.js binary was
compiled. Possible values are 'arm', 'arm64', 'ia32', 'mips',
'mipsel', 'ppc', 'ppc64', 's390', 's390x', and 'x64'.
The return value is equivalent to process.arch.
M os.constants
Added in: v6.3.0
Contains commonly used operating system-specific constants for error codes, process signals, and so on. The specific constants defined are described in OS constants.
M os.cpus()
Added in: v0.3.3
- Returns: Object[]
Returns an array of objects containing information about each logical CPU core.
The properties included on each object include:
modelstringspeednumber(in MHz)timesObjectusernumberThe number of milliseconds the CPU has spent in user mode.nicenumberThe number of milliseconds the CPU has spent in nice mode.sysnumberThe number of milliseconds the CPU has spent in sys mode.idlenumberThe number of milliseconds the CPU has spent in idle mode.irqnumberThe number of milliseconds the CPU has spent in irq mode.
JS
nice values are POSIX-only. On Windows, the nice values of all processors
are always 0.
M os.devNull
Added in: v16.3.0
The platform-specific file path of the null device.
\\.\nulon Windows/dev/nullon POSIX
M os.endianness()
Added in: v0.9.4
- Returns:
string
Returns a string identifying the endianness of the CPU for which the Node.js binary was compiled.
Possible values are 'BE' for big endian and 'LE' for little endian.
M os.freemem()
Added in: v0.3.3
- Returns:
integer
Returns the amount of free system memory in bytes as an integer.
M os.getPriority([pid])
Added in: v10.10.0
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.
M os.homedir()
Added in: v2.3.0
- Returns:
string
Returns the string path of the current user's home directory.
On POSIX, it uses the $HOME environment variable if defined. Otherwise it
uses the effective UID to look up the user's home directory.
On Windows, it uses the USERPROFILE environment variable if defined.
Otherwise it uses the path to the profile directory of the current user.
M os.hostname()
Added in: v0.3.3
- Returns:
string
Returns the host name of the operating system as a string.
M os.loadavg()
Added in: v0.3.3
- Returns: number[]
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.
The load average is a Unix-specific concept. On Windows, the return value is
always [0, 0, 0].
M os.networkInterfaces()
Added in: v0.6.0
- Returns:
Object
Returns an object containing 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:
addressstringThe assigned IPv4 or IPv6 addressnetmaskstringThe IPv4 or IPv6 network maskfamilystringEitherIPv4orIPv6macstringThe MAC address of the network interfaceinternalbooleantrueif the network interface is a loopback or similar interface that is not remotely accessible; otherwisefalsescopeidnumberThe numeric IPv6 scope ID (only specified whenfamilyisIPv6)cidrstringThe assigned IPv4 or IPv6 address with the routing prefix in CIDR notation. If thenetmaskis invalid, this property is set tonull.
JS
M os.platform()
Added in: v0.5.0
- Returns:
string
Returns a string identifying the operating system platform for which
the Node.js binary was compiled. The value is set at compile time.
Possible values are 'aix', 'darwin', 'freebsd','linux',
'openbsd', 'sunos', and 'win32'.
The return value is equivalent to process.platform.
The value 'android' may also be returned if Node.js is built on the Android
operating system. Android support is experimental.
M os.release()
Added in: v0.3.3
- Returns:
string
Returns the operating system as a string.
On POSIX systems, the operating system release is determined by calling
uname(3). On Windows, GetVersionExW() is used. See
https://en.wikipedia.org/wiki/Uname#Examples for more information.
M os.setPriority([pid, ]priority)
Added in: v10.10.0
pidintegerThe process ID to set scheduling priority for. Default:0.priorityintegerThe scheduling priority to assign to the process.
Attempts to set the scheduling priority for the process specified by pid. If
pid is not provided or is 0, the process ID of the current process is used.
The priority input must be an integer between -20 (high priority) and 19
(low priority). Due to differences between Unix priority levels and Windows
priority classes, priority is mapped to one of six priority constants in
os.constants.priority. When retrieving a process priority level, this range
mapping may cause the return value to be slightly different on Windows. To avoid
confusion, set priority to one of the priority constants.
On Windows, setting priority to PRIORITY_HIGHEST requires elevated user
privileges. Otherwise the set priority will be silently reduced to
PRIORITY_HIGH.
M os.tmpdir()
历史
| 版本 | 更改 |
|---|---|
| v2.0.0 | This function is now cross-platform consistent and no longer returns a path with a trailing slash on any platform. |
| v0.9.9 | Added in: v0.9.9 |
- Returns:
string
Returns the operating system's default directory for temporary files as a string.
M os.totalmem()
Added in: v0.3.3
- Returns:
integer
Returns the total amount of system memory in bytes as an integer.
M os.type()
Added in: v0.3.3
- Returns:
string
Returns the operating system name as returned by uname(3). For example, it
returns 'Linux' on Linux, 'Darwin' on macOS, and 'Windows_NT' on Windows.
See https://en.wikipedia.org/wiki/Uname#Examples for additional information
about the output of running uname(3) on various operating systems.
M os.uptime()
历史
| 版本 | 更改 |
|---|---|
| v10.0.0 | The result of this function no longer contains a fraction component on Windows. |
| v0.3.3 | Added in: v0.3.3 |
- Returns:
integer
Returns the system uptime in number of seconds.
M os.userInfo([options])
Added in: v6.0.0
optionsObjectencodingstringCharacter encoding used to interpret resulting strings. Ifencodingis set to'buffer', theusername,shell, andhomedirvalues will beBufferinstances. Default:'utf8'.
- Returns:
Object
Returns information about the currently effective user. On POSIX platforms,
this is typically a subset of the password file. 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 os.userInfo() is provided by the operating
system. This differs from the result of os.homedir(), which queries
environment variables for the home directory before falling back to the
operating system response.
Throws a SystemError if a user has no username or homedir.
M os.version()
Added in: v13.11.0, v12.17.0
- Returns
string
Returns a string identifying the kernel version.
On POSIX systems, the operating system release is determined by calling
uname(3). On Windows, RtlGetVersion() is used, and if it is not
available, GetVersionExW() will be used. See
https://en.wikipedia.org/wiki/Uname#Examples for more information.
M os.machine()
Added in: v16.18.0
- Returns
string
Returns the machine type as a string, such as arm, aarch64, mips,
mips64, ppc64, ppc64le, s390, s390x, i386, i686, x86_64.
On POSIX systems, the machine type is determined by calling
uname(3). On Windows, RtlGetVersion() is used, and if it is not
available, GetVersionExW() will be used. See
https://en.wikipedia.org/wiki/Uname#Examples for more information.
OS constants
The following constants are exported by os.constants.
Not all constants will be available on every operating system.
Signal constants
The following signal constants are exported by os.constants.signals.
| Constant | Description |
|---|---|
SIGHUP | Sent to indicate when a controlling terminal is closed or a parent process exits. |
SIGINT | Sent to indicate when a user wishes to interrupt a process (Ctrl+C). |
SIGQUIT | Sent to indicate when a user wishes to terminate a process and perform a core dump. |
SIGILL | Sent to a process to notify that it has attempted to perform an illegal, malformed, unknown, or privileged instruction. |
SIGTRAP | Sent to a process when an exception has occurred. |
SIGABRT | Sent to a process to request that it abort. |
SIGIOT | Synonym for SIGABRT |
SIGBUS | Sent to a process to notify that it has caused a bus error. |
SIGFPE | Sent to a process to notify that it has performed an illegal arithmetic operation. |
SIGKILL | Sent to a process to terminate it immediately. |
SIGUSR1 SIGUSR2 | Sent to a process to identify user-defined conditions. |
SIGSEGV | Sent to a process to notify of a segmentation fault. |
SIGPIPE | Sent to a process when it has attempted to write to a disconnected pipe. |
SIGALRM | Sent to a process when a system timer elapses. |
SIGTERM | Sent to a process to request termination. |
SIGCHLD | Sent to a process when a child process terminates. |
SIGSTKFLT | Sent to a process to indicate a stack fault on a coprocessor. |
SIGCONT | Sent to instruct the operating system to continue a paused process. |
SIGSTOP | Sent to instruct the operating system to halt a process. |
SIGTSTP | Sent to a process to request it to stop. |
SIGBREAK | Sent to indicate when a user wishes to interrupt a process. |
SIGTTIN | Sent to a process when it reads from the TTY while in the background. |
SIGTTOU | Sent to a process when it writes to the TTY while in the background. |
SIGURG | Sent to a process when a socket has urgent data to read. |
SIGXCPU | Sent to a process when it has exceeded its limit on CPU usage. |
SIGXFSZ | Sent to a process when it grows a file larger than the maximum allowed. |
SIGVTALRM | Sent to a process when a virtual timer has elapsed. |
SIGPROF | Sent to a process when a system timer has elapsed. |
SIGWINCH | Sent to a process when the controlling terminal has changed its size. |
SIGIO | Sent to a process when I/O is available. |
SIGPOLL | Synonym for SIGIO |
SIGLOST | Sent to a process when a file lock has been lost. |
SIGPWR | Sent to a process to notify of a power failure. |
SIGINFO | Synonym for SIGPWR |
SIGSYS | Sent to a process to notify of a bad argument. |
SIGUNUSED | Synonym for SIGSYS |
Error constants
The following error constants are exported by os.constants.errno.
POSIX error constants
| Constant | Description |
|---|---|
E2BIG | Indicates that the list of arguments is longer than expected. |
EACCES | Indicates that the operation did not have sufficient permissions. |
EADDRINUSE | Indicates that the network address is already in use. |
EADDRNOTAVAIL | Indicates that the network address is currently unavailable for use. |
EAFNOSUPPORT | Indicates that the network address family is not supported. |
EAGAIN | Indicates that there is no data available and to try the operation again later. |
EALREADY | Indicates that the socket already has a pending connection in progress. |
EBADF | Indicates that a file descriptor is not valid. |
EBADMSG | Indicates an invalid data message. |
EBUSY | Indicates that a device or resource is busy. |
ECANCELED | Indicates that an operation was canceled. |
ECHILD | Indicates that there are no child processes. |
ECONNABORTED | Indicates that the network connection has been aborted. |
ECONNREFUSED | Indicates that the network connection has been refused. |
ECONNRESET | Indicates that the network connection has been reset. |
EDEADLK | Indicates that a resource deadlock has been avoided. |
EDESTADDRREQ | Indicates that a destination address is required. |
EDOM | Indicates that an argument is out of the domain of the function. |
EDQUOT | Indicates that the disk quota has been exceeded. |
EEXIST | Indicates that the file already exists. |
EFAULT | Indicates an invalid pointer address. |
EFBIG | Indicates that the file is too large. |
EHOSTUNREACH | Indicates that the host is unreachable. |
EIDRM | Indicates that the identifier has been removed. |
EILSEQ | Indicates an illegal byte sequence. |
EINPROGRESS | Indicates that an operation is already in progress. |
EINTR | Indicates that a function call was interrupted. |
EINVAL | Indicates that an invalid argument was provided. |
EIO | Indicates an otherwise unspecified I/O error. |
EISCONN | Indicates that the socket is connected. |
EISDIR | Indicates that the path is a directory. |
ELOOP | Indicates too many levels of symbolic links in a path. |
EMFILE | Indicates that there are too many open files. |
EMLINK | Indicates that there are too many hard links to a file. |
EMSGSIZE | Indicates that the provided message is too long. |
EMULTIHOP | Indicates that a multihop was attempted. |
ENAMETOOLONG | Indicates that the filename is too long. |
ENETDOWN | Indicates that the network is down. |
ENETRESET | Indicates that the connection has been aborted by the network. |
ENETUNREACH | Indicates that the network is unreachable. |
ENFILE | Indicates too many open files in the system. |
ENOBUFS | Indicates that no buffer space is available. |
ENODATA | Indicates that no message is available on the stream head read queue. |
ENODEV | Indicates that there is no such device. |
ENOENT | Indicates that there is no such file or directory. |
ENOEXEC | Indicates an exec format error. |
ENOLCK | Indicates that there are no locks available. |
ENOLINK | Indications that a link has been severed. |
ENOMEM | Indicates that there is not enough space. |
ENOMSG | Indicates that there is no message of the desired type. |
ENOPROTOOPT | Indicates that a given protocol is not available. |
ENOSPC | Indicates that there is no space available on the device. |
ENOSR | Indicates that there are no stream resources available. |
ENOSTR | Indicates that a given resource is not a stream. |
ENOSYS | Indicates that a function has not been implemented. |
ENOTCONN | Indicates that the socket is not connected. |
ENOTDIR | Indicates that the path is not a directory. |
ENOTEMPTY | Indicates that the directory is not empty. |
ENOTSOCK | Indicates that the given item is not a socket. |
ENOTSUP | Indicates that a given operation is not supported. |
ENOTTY | Indicates an inappropriate I/O control operation. |
ENXIO | Indicates no such device or address. |
EOPNOTSUPP | Indicates that an operation is not supported on the socket. AlthoughENOTSUP and EOPNOTSUPP have the same value on Linux, according to POSIX.1 these error values should be distinct.) |
EOVERFLOW | Indicates that a value is too large to be stored in a given data type. |
EPERM | Indicates that the operation is not permitted. |
EPIPE | Indicates a broken pipe. |
EPROTO | Indicates a protocol error. |
EPROTONOSUPPORT | Indicates that a protocol is not supported. |
EPROTOTYPE | Indicates the wrong type of protocol for a socket. |
ERANGE | Indicates that the results are too large. |
EROFS | Indicates that the file system is read only. |
ESPIPE | Indicates an invalid seek operation. |
ESRCH | Indicates that there is no such process. |
ESTALE | Indicates that the file handle is stale. |
ETIME | Indicates an expired timer. |
ETIMEDOUT | Indicates that the connection timed out. |
ETXTBSY | Indicates that a text file is busy. |
EWOULDBLOCK | Indicates that the operation would block. |
EXDEV | Indicates an improper link. |
Windows-specific error constants
The following error codes are specific to the Windows operating system.
| Constant | Description |
|---|---|
WSAEINTR | Indicates an interrupted function call. |
WSAEBADF | Indicates an invalid file handle. |
WSAEACCES | Indicates insufficient permissions to complete the operation. |
WSAEFAULT | Indicates an invalid pointer address. |
WSAEINVAL | Indicates that an invalid argument was passed. |
WSAEMFILE | Indicates that there are too many open files. |
WSAEWOULDBLOCK | Indicates that a resource is temporarily unavailable. |
WSAEINPROGRESS | Indicates that an operation is currently in progress. |
WSAEALREADY | Indicates that an operation is already in progress. |
WSAENOTSOCK | Indicates that the resource is not a socket. |
WSAEDESTADDRREQ | Indicates that a destination address is required. |
WSAEMSGSIZE | Indicates that the message size is too long. |
WSAEPROTOTYPE | Indicates the wrong protocol type for the socket. |
WSAENOPROTOOPT | Indicates a bad protocol option. |
WSAEPROTONOSUPPORT | Indicates that the protocol is not supported. |
WSAESOCKTNOSUPPORT | Indicates that the socket type is not supported. |
WSAEOPNOTSUPP | Indicates that the operation is not supported. |
WSAEPFNOSUPPORT | Indicates that the protocol family is not supported. |
WSAEAFNOSUPPORT | Indicates that the address family is not supported. |
WSAEADDRINUSE | Indicates that the network address is already in use. |
WSAEADDRNOTAVAIL | Indicates that the network address is not available. |
WSAENETDOWN | Indicates that the network is down. |
WSAENETUNREACH | Indicates that the network is unreachable. |
WSAENETRESET | Indicates that the network connection has been reset. |
WSAECONNABORTED | Indicates that the connection has been aborted. |
WSAECONNRESET | Indicates that the connection has been reset by the peer. |
WSAENOBUFS | Indicates that there is no buffer space available. |
WSAEISCONN | Indicates that the socket is already connected. |
WSAENOTCONN | Indicates that the socket is not connected. |
WSAESHUTDOWN | Indicates that data cannot be sent after the socket has been shutdown. |
WSAETOOMANYREFS | Indicates that there are too many references. |
WSAETIMEDOUT | Indicates that the connection has timed out. |
WSAECONNREFUSED | Indicates that the connection has been refused. |
WSAELOOP | Indicates that a name cannot be translated. |
WSAENAMETOOLONG | Indicates that a name was too long. |
WSAEHOSTDOWN | Indicates that a network host is down. |
WSAEHOSTUNREACH | Indicates that there is no route to a network host. |
WSAENOTEMPTY | Indicates that the directory is not empty. |
WSAEPROCLIM | Indicates that there are too many processes. |
WSAEUSERS | Indicates that the user quota has been exceeded. |
WSAEDQUOT | Indicates that the disk quota has been exceeded. |
WSAESTALE | Indicates a stale file handle reference. |
WSAEREMOTE | Indicates that the item is remote. |
WSASYSNOTREADY | Indicates that the network subsystem is not ready. |
WSAVERNOTSUPPORTED | Indicates that the winsock.dll version is out of range. |
WSANOTINITIALISED | Indicates that successful WSAStartup has not yet been performed. |
WSAEDISCON | Indicates that a graceful shutdown is in progress. |
WSAENOMORE | Indicates that there are no more results. |
WSAECANCELLED | Indicates that an operation has been canceled. |
WSAEINVALIDPROCTABLE | Indicates that the procedure call table is invalid. |
WSAEINVALIDPROVIDER | Indicates an invalid service provider. |
WSAEPROVIDERFAILEDINIT | Indicates that the service provider failed to initialized. |
WSASYSCALLFAILURE | Indicates a system call failure. |
WSASERVICE_NOT_FOUND | Indicates that a service was not found. |
WSATYPE_NOT_FOUND | Indicates that a class type was not found. |
WSA_E_NO_MORE | Indicates that there are no more results. |
WSA_E_CANCELLED | Indicates that the call was canceled. |
WSAEREFUSED | Indicates that a database query was refused. |
dlopen constants
If available on the operating system, the following constants
are exported in os.constants.dlopen. See dlopen(3) for detailed
information.
| Constant | Description |
|---|---|
RTLD_LAZY | Perform lazy binding. Node.js sets this flag by default. |
RTLD_NOW | Resolve all undefined symbols in the library before dlopen(3) returns. |
RTLD_GLOBAL | Symbols defined by the library will be made available for symbol resolution of subsequently loaded libraries. |
RTLD_LOCAL | The converse of RTLD_GLOBAL. This is the default behavior if neither flag is specified. |
RTLD_DEEPBIND | Make a self-contained library use its own symbols in preference to symbols from previously loaded libraries. |
Priority constants
Added in: v10.10.0
The following process scheduling constants are exported by
os.constants.priority.
| Constant | Description |
|---|---|
PRIORITY_LOW | The lowest process scheduling priority. This corresponds toIDLE_PRIORITY_CLASS on Windows, and a nice value of19 on all other platforms. |
PRIORITY_BELOW_NORMAL | The process scheduling priority above PRIORITY_LOW and below PRIORITY_NORMAL. This corresponds toBELOW_NORMAL_PRIORITY_CLASS on Windows, and a nice value of10 on all other platforms. |
PRIORITY_NORMAL | The default process scheduling priority. This corresponds toNORMAL_PRIORITY_CLASS on Windows, and a nice value of0 on all other platforms. |
PRIORITY_ABOVE_NORMAL | The process scheduling priority above PRIORITY_NORMAL and below PRIORITY_HIGH. This corresponds toABOVE_NORMAL_PRIORITY_CLASS on Windows, and a nice value of-7 on all other platforms. |
PRIORITY_HIGH | The process scheduling priority above PRIORITY_ABOVE_NORMALand below PRIORITY_HIGHEST. This corresponds toHIGH_PRIORITY_CLASS on Windows, and a nice value of-14 on all other platforms. |
PRIORITY_HIGHEST | The highest process scheduling priority. This corresponds toREALTIME_PRIORITY_CLASS on Windows, and a nice value of-20 on all other platforms. |
libuv constants
| Constant | Description |
|---|---|
UV_UDP_REUSEADDR |