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NODE(1) General Commands Manual NODE(1)

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 remaining 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.

Aborting instead of exiting causes a core file to be generated for analysis.
Print source-able bash completion script for Node.js.
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.
The directory where the CPU profiles generated by --cpu-prof will be placed.
The sampling interval in microseconds for the CPU profiles generated by --cpu-prof. The default is 1000.
File name of the V8 CPU profile generated with --cpu-prof
=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`.
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-compliant crypto at startup. Requires Node.js to be built with ./configure --openssl-fips.
Enable experimental Source Map V3 support for stack traces.
Enable experimental ES modules support for import.meta.resolve().
Enable experimental JSON interop support for the ES Module loader.
=module
Specify the module to use as a custom module loader.
Use the specified file as a security policy.
Enable experimental top-level await keyword support in REPL.
Select extension resolution algorithm for ES Modules; either 'explicit' (default) or 'node'
Enable experimental ES module support in VM module.
Enable experimental WebAssembly System Interface support.
Enable experimental WebAssembly module support.
Disable loading native addons that are not context-aware.
Force FIPS-compliant crypto on startup (Cannot be disabled from script code). Same requirements as --enable-fips.
Enable experimental frozen intrinsics support.
=signal
Generate heap snapshot on specified signal.
Start the V8 heap profiler on start up, and write the heap profile 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.
The directory where the heap profiles generated by --heap-prof will be placed.
The average sampling interval in bytes for the heap profiles generated by --heap-prof. The default is 512 * 1024.
File name of the V8 heap profile generated with --heap-prof
=library
Chooses an HTTP parser library. Available values are llhttp or legacy.
=milliseconds
Overrides the default value for server socket timeout.
=file
Specify ICU data load path. Overrides NODE_ICU_DATA.
=type
Set the module resolution type for input via --eval, --print or STDIN.
=[host:]port
Activate inspector on host:port and break at start of user script.
=[host:]port
Set the host:port to be used when the inspector is activated.
Specify how the inspector WebSocket URL is exposed. Valid values are stderr and http. Default is stderr,http.
=[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.

Use an insecure HTTP parser that accepts invalid HTTP headers. This may allow interoperability with non-conformant HTTP implementations. It may also allow request smuggling and other HTTP attacks that rely on invalid headers being accepted. Avoid using this option.
Disable runtime allocation of executable memory. This may be required on some platforms for security reasons. It can also reduce attack surface on other platforms, but the performance impact may be severe.

This flag is inherited from V8 and is subject to change upstream. It may disappear in a non-semver-major release.

=size
Specify the maximum size of HTTP headers in bytes. Defaults to 8KB.
This option is a no-op. It is kept for compatibility.
Silence deprecation warnings.
Disable runtime checks for `async_hooks`. These will still be enabled dynamically when `async_hooks` is enabled.
Silence all process warnings (including deprecations).
=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.
Emit pending deprecation warnings.
=sri
Instructs Node.js to error prior to running any code if the policy does not have the specified integrity. It expects a Subresource Integrity string as a parameter.
Instructs the module loader to preserve symbolic links when resolving and caching modules other than the main module.
Instructs the module loader to preserve symbolic links when resolving and caching the main module.
Generate V8 profiler output.
Process V8 profiler output generated using the V8 option --prof.
=file
Write process warnings to the given file instead of printing to stderr.
Write diagnostic reports in a compact format, single-line JSON.
Location at which the diagnostic report will be generated.
Name of the file to which the diagnostic report will be written.
Enables the diagnostic report to be triggered on fatal errors (internal errors within the Node.js runtime such as out of memory) that leads to termination of the application. Useful to inspect various diagnostic data elements such as heap, stack, event loop state, resource consumption etc. to reason about the fatal error.
Enables diagnostic report to be generated upon receiving the specified (or predefined) signal to the running Node.js process. Default signal is SIGUSR2.
Sets or resets the signal for diagnostic report generation (not supported on Windows). Default signal is SIGUSR2.
Enables diagnostic report to be generated on un-caught exceptions. Useful when inspecting JavaScript stack in conjunction with native stack and other runtime environment data.
Throw errors for deprecations.
=title
Specify process.title on startup.
=list
Specify an alternative default TLS cipher list. Requires Node.js to be built with crypto support. (Default)
=file
Log TLS key material to a file. The key material is in NSS SSLKEYLOGFILE format and can be used by software (such as Wireshark) to decrypt the TLS traffic.
Set default maxVersion to 'TLSv1.2'. Use to disable support for TLSv1.3.
Set default maxVersion to 'TLSv1.3'. Use to enable support for TLSv1.3.
Set default minVersion to 'TLSv1'. Use for compatibility with old TLS clients or servers.
Set default minVersion to 'TLSv1.1'. Use for compatibility with old TLS clients or servers.
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.
Set default minVersion to 'TLSv1.3'. Use to disable support for TLSv1.2 in favour of TLSv1.3, which is more secure.
Print stack traces for deprecations.
categories
A comma-separated list of categories that should be traced when trace event tracing is enabled using --trace-events-enabled.
pattern
Template string specifying the filepath for the trace event data, it supports ${rotation} and ${pid}.
Enable the collection of trace event tracing information.
Prints a stack trace whenever an environment is exited proactively, i.e. invoking `process.exit()`.
Prints a stack trace on SIGINT.
Print a stack trace whenever synchronous I/O is detected after the first turn of the event loop.
Prints TLS packet trace information to stderr.
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 instance).

Enabling this option may affect garbage collection behavior negatively.

Print stack traces for process warnings (including deprecations).
Track heap object allocations for heap snapshots.
Define the behavior for unhandled rejections. Can be one of `strict` (raise an error), `warn` (enforce warnings) or `none` (silence warnings).
, --use-openssl-ca
Use bundled Mozilla CA store as supplied by current Node.js version 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 administrators. OpenSSL CA store location is dependent on configuration of the OpenSSL library but this can be altered at runtime using environment variables.

See SSL_CERT_DIR and SSL_CERT_FILE.

=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, reporting it to stderr), or `silent` (map and silently ignore failure).

Print V8 command-line options.
=num
Set V8's thread pool size which will be used to allocate background jobs. If set to 0 then V8 will choose an appropriate size of the thread pool based on the number of online processors. If the value provided is larger than V8's maximum, then the largest value will be chosen.
Automatically zero-fills all newly allocated Buffer and SlowBuffer instances.
, --check
Check the script's syntax without executing it. Exits with an error code if script is invalid.
, --eval string
Evaluate string as JavaScript.
, --help
Print command-line options. The output of this option is less detailed than this document.
, --interactive
Open the REPL even if stdin does not appear to be a terminal.
, --print string
Identical to -e, but prints the result.
, --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.
, --version
Print node's version.

ENVIRONMENT

modules...
Comma-separated list of core modules that should print debug information.
modules...
Comma-separated list of C++ core modules that should print debug information.
When set to 1, colors will not be used in the REPL.
file
When set, the well-known “root” CAs (like VeriSign) will be extended 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.

file
Data path for ICU (Intl object) data. Will extend linked-in data when compiled with small-icu support.
When set to 1, process warnings are silenced.
options...
A space-separated list of command-line options, which are interpreted 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 environment is used, such as --print or a script file.
directories...
A colon-separated list of directories prefixed to the module search path.
When set to 1, emit pending deprecation warnings.
When set to 1, the module loader preserves symbolic links when resolving and caching modules.
file
Write process warnings to the given file instead of printing to stderr. Equivalent to passing --redirect-warnings file on command-line.
file
Path to the file used to store persistent REPL history. The default path is ~/.node_repl_history, which is overridden by this variable. Setting the value to an empty string ("" or " ") will disable persistent REPL history.
When set to 0, TLS certificate validation is disabled.
dir
When set, Node.js writes JavaScript code coverage information to dir.
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 environment variable is ignored.

dir
If --use-openssl-ca is enabled, this overrides and sets OpenSSL's directory containing trusted certificates.
file
If --use-openssl-ca is enabled, this overrides and sets OpenSSL's file containing trusted certificates.
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 license.

Node.js also includes external libraries that are available under a variety of licenses. See https://github.com/nodejs/node/blob/master/LICENSE for the full license text.

SEE ALSO

Website: https://nodejs.org/

Documentation: https://nodejs.org/api/

GitHub repository & Issue Tracker: https://github.com/nodejs/node

IRC (general questions): chat.freenode.net #node.js (unofficial)

IRC (Node.js core development): chat.freenode.net #node-dev

AUTHORS

Written and maintained by 1000+ contributors: https://github.com/nodejs/node/blob/master/AUTHORS
2018