NAME
node — server-side JavaScript runtime
SYNOPSIS
node [options] [v8-options] [-e string | script.js | -] [--]
[arguments ...]
node inspect [-e string | script.js | - | <host>:<port>] ...
node [--v8-options]
DESCRIPTION
Node.js is a set of libraries for JavaScript which allows it to be used
outside of the browser. It is primarily focused on creating simple,
easy-to-build network clients and servers.
Execute node without arguments to start a REPL.
OPTIONS
- Alias for stdin, analogous to the use of - in other command-line
utilities. The executed script is read from stdin, and remain-
ing arguments are passed to the script.
-- Indicate the end of command-line options. Pass the rest of the
arguments to the script.
If no script filename or eval/print script is supplied prior to
this, then the next argument will be used as a script filename.
--abort-on-uncaught-exception
Aborting instead of exiting causes a core file to be generated
for analysis.
--allow-fs-read
Allow file system read access when using the permission model.
--allow-fs-write
Allow file system write access when using the permission model.
--allow-addons
Allow using native addons when using the permission model.
--allow-child-process
Allow spawning process when using the permission model.
--allow-wasi
Allow execution of WASI when using the permission model.
--allow-worker
Allow creating worker threads when using the permission model.
--completion-bash
Print source-able bash completion script for Node.js.
-C, --conditions string
Use custom conditional exports conditions. string
--cpu-prof
Start the V8 CPU profiler on start up, and write the CPU profile
to disk before exit. If --cpu-prof-dir is not specified, the
profile will be written to the current working directory with a
generated file name.
--cpu-prof-dir
The directory where the CPU profiles generated by --cpu-prof
will be placed. The default value is controlled by the
--diagnostic-dir. command-line option.
--cpu-prof-interval
The sampling interval in microseconds for the CPU profiles gen-
erated by --cpu-prof. The default is 1000.
--cpu-prof-name
File name of the V8 CPU profile generated with --cpu-prof.
--diagnostic-dir
Set the directory for all diagnostic output files. Default is
current working directory. Set the directory to which all diag-
nostic output files will be written to. Defaults to current
working directory. Affects the default output directory of:
--cpu-prof-dir. --heap-prof-dir. --redirect-warnings.
--disable-proto=mode
Disable the `Object.prototype.__proto__` property. If mode is
`delete`, the property will be removed entirely. If mode is
`throw`, accesses to the property will throw an exception with
the code `ERR_PROTO_ACCESS`.
--disable-wasm-trap-handler=mode
Disable trap-handler-based WebAssembly bound checks and fall
back to inline bound checks so that WebAssembly can be run with
limited virtual memory.
--disallow-code-generation-from-strings
Make built-in language features like `eval` and `new Function`
that generate code from strings throw an exception instead. This
does not affect the Node.js `vm` module.
--enable-fips
Enable FIPS-compliant crypto at startup. Requires Node.js to be
built with ./configure --openssl-fips.
--enable-source-maps
Enable Source Map V3 support for stack traces.
--experimental-default-type=type
Interpret as either ES modules or CommonJS modules input via
--eval or STDIN, when --input-type is unspecified;
--experimental-import-meta-resolve
Enable experimental ES modules support for import.meta.re-
solve().
--experimental-loader=module
Specify the module to use as a custom module loader.
--experimental-network-imports
Enable experimental support for loading modules using `import`
over `https:`.
--experimental-permission
Enable the experimental permission model.
--experimental-policy
Use the specified file as a security policy.
--experimental-shadow-realm
Use this flag to enable ShadowRealm support.
--experimental-test-coverage
Enable code coverage in the test runner.
--experimental-test-module-mocks
Enable module mocking in the test runner.
--experimental-eventsource
Enable experimental support for the EventSource Web API.
--experimental-websocket
Enable experimental support for the WebSocket API.
--no-experimental-fetch
Disable experimental support for the Fetch API.
--no-experimental-global-customevent
Disable exposition of the CustomEvent on the global scope.
--no-experimental-global-webcrypto
Disable exposition of the Web Crypto API on the global scope.
--no-experimental-repl-await
Disable top-level await keyword support in REPL.
--experimental-vm-modules
Enable experimental ES module support in VM module.
--experimental-wasi-unstable-preview1
Enable experimental WebAssembly System Interface support. This
flag is no longer required as WASI is enabled by default.
--experimental-wasm-modules
Enable experimental WebAssembly module support.
--force-context-aware
Disable loading native addons that are not context-aware.
--force-fips
Force FIPS-compliant crypto on startup (Cannot be disabled from
script code). Same requirements as --enable-fips.
--frozen-intrinsics
Enable experimental frozen intrinsics support.
--heapsnapshot-near-heap-limit=max_count
Generate heap snapshot when the V8 heap usage is approaching the
heap limit. No more than the specified number of snapshots will
be generated.
--heapsnapshot-signal=signal
Generate heap snapshot on specified signal.
--heap-prof
Start the V8 heap profiler on start up, and write the heap pro-
file to disk before exit. If --heap-prof-dir is not specified,
the profile will be written to the current working directory
with a generated file name.
--heap-prof-dir
The directory where the heap profiles generated by --heap-prof
will be placed. The default value is controlled by the
--diagnostic-dir. command-line option.
--heap-prof-interval
The average sampling interval in bytes for the heap profiles
generated by --heap-prof. The default is 512 * 1024.
--heap-prof-name
File name of the V8 heap profile generated with --heap-prof.
--icu-data-dir=file
Specify ICU data load path. Overrides NODE_ICU_DATA.
--input-type=type
Set the module resolution type for input via --eval, --print or
STDIN.
--inspect-brk=[host:]port
Activate inspector on host:port and break at start of user
script.
--inspect-port=[host:]port
Set the host:port to be used when the inspector is activated.
--inspect-publish-uid=stderr,http
Specify how the inspector WebSocket URL is exposed. Valid val-
ues are stderr and http. Default is stderr,http.
--inspect-wait=[host:]port
Activate inspector on host:port and wait for debugger to be at-
tached.
--inspect=[host:]port
Activate inspector on host:port. Default is 127.0.0.1:9229.
V8 Inspector integration allows attaching Chrome DevTools and
IDEs to Node.js instances for debugging and profiling. It uses
the Chrome DevTools Protocol.
--insecure-http-parser
Use an insecure HTTP parser that accepts invalid HTTP headers.
This may allow interoperability with non-conformant HTTP imple-
mentations. It may also allow request smuggling and other HTTP
attacks that rely on invalid headers being accepted. Avoid using
this option.
--jitless
Disable runtime allocation of executable memory. This may be re-
quired on some platforms for security reasons. It can also re-
duce attack surface on other platforms, but the performance im-
pact may be severe.
This flag is inherited from V8 and is subject to change up-
stream. It may disappear in a non-semver-major release.
--max-http-header-size=size
Specify the maximum size of HTTP headers in bytes. Defaults to
16 KiB.
--napi-modules
This option is a no-op. It is kept for compatibility.
--no-deprecation
Silence deprecation warnings.
--no-extra-info-on-fatal-exception
Hide extra information on fatal exception that causes exit.
--no-force-async-hooks-checks
Disable runtime checks for `async_hooks`. These will still be
enabled dynamically when `async_hooks` is enabled.
--no-addons
Disable the `node-addons` exports condition as well as disable
loading native addons. When `--no-addons` is specified, calling
`process.dlopen` or requiring a native C++ addon will fail and
throw an exception.
--no-global-search-paths
Do not search modules from global paths.
--no-warnings
Silence all process warnings (including deprecations).
--node-memory-debug
Enable extra debug checks for memory leaks in Node.js internals.
This is usually only useful for developers debugging Node.js it-
self.
--openssl-config=file
Load an OpenSSL configuration file on startup. Among other
uses, this can be used to enable FIPS-compliant crypto if
Node.js is built with ./configure --openssl-fips.
--pending-deprecation
Emit pending deprecation warnings.
--policy-integrity=sri
Instructs Node.js to error prior to running any code if the pol-
icy does not have the specified integrity. It expects a Subre-
source Integrity string as a parameter.
--preserve-symlinks
Instructs the module loader to preserve symbolic links when re-
solving and caching modules other than the main module.
--preserve-symlinks-main
Instructs the module loader to preserve symbolic links when re-
solving and caching the main module.
--prof Generate V8 profiler output.
--prof-process
Process V8 profiler output generated using the V8 option --prof.
--redirect-warnings=file
Write process warnings to the given file instead of printing to
stderr.
--report-compact
Write diagnostic reports in a compact format, single-line JSON.
--report-dir --report-directory
Location at which the diagnostic report will be generated. The
`file` name may be an absolute path. If it is not, the default
directory it will be written to is controlled by the
--diagnostic-dir. command-line option.
--report-filename
Name of the file to which the diagnostic report will be written.
--report-on-fatalerror
Enables the diagnostic report to be triggered on fatal errors
(internal errors within the Node.js runtime such as out of mem-
ory) that leads to termination of the application. Useful to in-
spect various diagnostic data elements such as heap, stack,
event loop state, resource consumption etc. to reason about the
fatal error.
--report-on-signal
Enables diagnostic report to be generated upon receiving the
specified (or predefined) signal to the running Node.js process.
Default signal is SIGUSR2.
--report-signal
Sets or resets the signal for diagnostic report generation (not
supported on Windows). Default signal is SIGUSR2.
--report-uncaught-exception
Enables diagnostic report to be generated on un-caught excep-
tions. Useful when inspecting JavaScript stack in conjunction
with native stack and other runtime environment data.
--secure-heap=n
Specify the size of the OpenSSL secure heap. Any value less than
2 disables the secure heap. The default is 0. The value must be
a power of two.
--secure-heap-min=n
Specify the minimum allocation from the OpenSSL secure heap. The
default is 2. The value must be a power of two.
--test Starts the Node.js command line test runner.
--test-concurrency
The maximum number of test files that the test runner CLI will
execute concurrently.
--test-force-exit
Configures the test runner to exit the process once all known
tests have finished executing even if the event loop would oth-
erwise remain active.
--test-name-pattern
A regular expression that configures the test runner to only ex-
ecute tests whose name matches the provided pattern.
--test-reporter
A test reporter to use when running tests.
--test-reporter-destination
The destination for the corresponding test reporter.
--test-only
Configures the test runner to only execute top level tests that
have the `only` option set.
--test-shard
Test suite shard to execute in a format of <index>/<total>.
--test-timeout
A number of milliseconds the test execution will fail after.
--throw-deprecation
Throw errors for deprecations.
--title=title
Specify process.title on startup.
--tls-cipher-list=list
Specify an alternative default TLS cipher list. Requires
Node.js to be built with crypto support. (Default)
--tls-keylog=file
Log TLS key material to a file. The key material is in NSS SS-
LKEYLOGFILE format and can be used by software (such as Wire-
shark) to decrypt the TLS traffic.
--tls-max-v1.2
Set default maxVersion to 'TLSv1.2'. Use to disable support for
TLSv1.3.
--tls-max-v1.3
Set default maxVersion to 'TLSv1.3'. Use to enable support for
TLSv1.3.
--tls-min-v1.0
Set default minVersion to 'TLSv1'. Use for compatibility with
old TLS clients or servers.
--tls-min-v1.1
Set default minVersion to 'TLSv1.1'. Use for compatibility with
old TLS clients or servers.
--tls-min-v1.2
Set default minVersion to 'TLSv1.2'. This is the default for
12.x and later, but the option is supported for compatibility
with older Node.js versions.
--tls-min-v1.3
Set default minVersion to 'TLSv1.3'. Use to disable support for
TLSv1.2 in favour of TLSv1.3, which is more secure.
--trace-atomics-wait
Print short summaries of calls to Atomics.wait(). This flag is
deprecated.
--trace-deprecation
Print stack traces for deprecations.
--trace-event-categories categories
A comma-separated list of categories that should be traced when
trace event tracing is enabled using --trace-events-enabled.
--trace-event-file-pattern pattern
Template string specifying the filepath for the trace event
data, it supports ${rotation} and ${pid}.
--trace-events-enabled
Enable the collection of trace event tracing information.
--trace-exit
Prints a stack trace whenever an environment is exited proac-
tively, i.e. invoking `process.exit()`.
--trace-sigint
Prints a stack trace on SIGINT.
--trace-sync-io
Print a stack trace whenever synchronous I/O is detected after
the first turn of the event loop.
--trace-tls
Prints TLS packet trace information to stderr.
--trace-uncaught
Print stack traces for uncaught exceptions; usually, the stack
trace associated with the creation of an Error is printed,
whereas this makes Node.js also print the stack trace associated
with throwing the value (which does not need to be an Error in-
stance).
Enabling this option may affect garbage collection behavior neg-
atively.
--trace-warnings
Print stack traces for process warnings (including depreca-
tions).
--track-heap-objects
Track heap object allocations for heap snapshots.
--unhandled-rejections=mode
Define the behavior for unhandled rejections. Can be one of
`strict` (raise an error), `warn` (enforce warnings) or `none`
(silence warnings).
--use-bundled-ca, --use-openssl-ca
Use bundled Mozilla CA store as supplied by current Node.js ver-
sion or use OpenSSL's default CA store. The default store is
selectable at build-time.
The bundled CA store, as supplied by Node.js, is a snapshot of
Mozilla CA store that is fixed at release time. It is identical
on all supported platforms.
Using OpenSSL store allows for external modifications of the
store. For most Linux and BSD distributions, this store is
maintained by the distribution maintainers and system adminis-
trators. OpenSSL CA store location is dependent on configura-
tion of the OpenSSL library but this can be altered at runtime
using environment variables.
See SSL_CERT_DIR and SSL_CERT_FILE.
--use-largepages=mode
Re-map the Node.js static code to large memory pages at startup.
If supported on the target system, this will cause the Node.js
static code to be moved onto 2 MiB pages instead of 4 KiB pages.
mode must have one of the following values: `off` (the default
value, meaning do not map), `on` (map and ignore failure, re-
porting it to stderr), or `silent` (map and silently ignore
failure).
--v8-options
Print V8 command-line options.
--v8-pool-size=num
Set V8's thread pool size which will be used to allocate back-
ground jobs. If set to 0 then V8 will choose an appropriate
size of the thread pool based on the number of online proces-
sors. If the value provided is larger than V8's maximum, then
the largest value will be chosen.
--zero-fill-buffers
Automatically zero-fills all newly allocated Buffer and Slow-
Buffer instances.
-c, --check
Check the script's syntax without executing it. Exits with an
error code if script is invalid.
-e, --eval string
Evaluate string as JavaScript.
-h, --help
Print command-line options. The output of this option is less
detailed than this document.
-i, --interactive
Open the REPL even if stdin does not appear to be a terminal.
-p, --print string
Identical to -e, but prints the result.
-r, --require module
Preload the specified module at startup. Follows `require()`'s
module resolution rules. module may be either a path to a file,
or a Node.js module name.
-v, --version
Print node's version.
ENVIRONMENT
FORCE_COLOR
Used to enable ANSI colorized output. The value may be one of: 1
, true , or an empty string to indicate 16-color support, 2 to
indicate 256-color support, or 3 to indicate 16 million-color
support. When used and set to a supported value, both the
NO_COLOR and NODE_DISABLE_COLORS environment variables are ig-
nored. Any other value will result in colorized output being
disabled.
NO_COLOR
Alias for NODE_DISABLE_COLORS
NODE_DEBUG modules...
Comma-separated list of core modules that should print debug in-
formation.
NODE_DEBUG_NATIVE modules...
Comma-separated list of C++ core modules that should print debug
information.
NODE_DISABLE_COLORS
When set to 1, colors will not be used in the REPL.
NODE_EXTRA_CA_CERTS file
When set, the well-known “root” CAs (like VeriSign) will be ex-
tended with the extra certificates in file. The file should
consist of one or more trusted certificates in PEM format.
If file is missing or misformatted, a message will be emitted
once using process.emitWarning(), but any errors are otherwise
ignored.
This environment variable is ignored when `node` runs as setuid
root or has Linux file capabilities set.
The NODE_EXTRA_CA_CERTS environment variable is only read when
the Node.js process is first launched. Changing the value at
runtime using process.env.NODE_EXTRA_CA_CERTS has no effect on
the current process.
NODE_ICU_DATA file
Data path for ICU (Intl object) data. Will extend linked-in
data when compiled with small-icu support.
NODE_NO_WARNINGS
When set to 1, process warnings are silenced.
NODE_OPTIONS options...
A space-separated list of command-line options, which are inter-
preted as if they had been specified on the command line before
the actual command (so they can be overridden). Node.js will
exit with an error if an option that is not allowed in the envi-
ronment is used, such as --print or a script file.
NODE_PATH directories...
A colon-separated list of directories prefixed to the module
search path.
NODE_PENDING_DEPRECATION
When set to 1, emit pending deprecation warnings.
NODE_PRESERVE_SYMLINKS
When set to 1, the module loader preserves symbolic links when
resolving and caching modules.
NODE_REDIRECT_WARNINGS file
Write process warnings to the given file instead of printing to
stderr. Equivalent to passing --redirect-warnings file on the
command line.
NODE_REPL_HISTORY file
Path to the file used to store persistent REPL history. The de-
fault path is ~/.node_repl_history, which is overridden by this
variable. Setting the value to an empty string ("" or " ") will
disable persistent REPL history.
NODE_REPL_EXTERNAL_MODULE file
Path to a Node.js module which will be loaded in place of the
built-in REPL. Overriding this value to an empty string (`''`)
will use the built-in REPL.
NODE_SKIP_PLATFORM_CHECK
When set to 1, the check for a supported platform is skipped
during Node.js startup. Node.js might not execute correctly.
Any issues encountered on unsupported platforms will not be
fixed.
NODE_TLS_REJECT_UNAUTHORIZED
When set to 0, TLS certificate validation is disabled.
NODE_V8_COVERAGE dir
When set, Node.js writes JavaScript code coverage information to
dir.
OPENSSL_CONF file
Load an OpenSSL configuration file on startup. Among other
uses, this can be used to enable FIPS-compliant crypto if
Node.js is built with ./configure --openssl-fips.
If the --openssl-config command-line option is used, this envi-
ronment variable is ignored.
SSL_CERT_DIR dir
If --use-openssl-ca is enabled, this overrides and sets
OpenSSL's directory containing trusted certificates.
SSL_CERT_FILE file
If --use-openssl-ca is enabled, this overrides and sets
OpenSSL's file containing trusted certificates.
TZ Specify the timezone configuration.
UV_THREADPOOL_SIZE size
Sets the number of threads used in libuv's threadpool to size.
BUGS
Bugs are tracked in GitHub Issues: https://github.com/nodejs/node/issues
COPYRIGHT
Copyright Node.js contributors. Node.js is available under the MIT li-
cense.
Node.js also includes external libraries that are available under a va-
riety of licenses. See https://github.com/nodejs/node/blob/HEAD/LICENSE
for the full license text.
SEE ALSO
Website: https://nodejs.org/
Documentation: https://nodejs.org/api/
GitHub repository and issue tracker: https://github.com/nodejs/node
2018 NODE(1)
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