探客时代
README
n – Interactively Manage Your Node.js Versions
Node.js version management: no subshells, no profile setup, no convoluted API, just simple.
- [n – Interactively Manage Your Node.js Versions](#n--interactively-manage-your-nodejs-versions)
Supported Platforms
n is supported on macOS, Linux, including with Windows Subsystem for Linux, and various other unix-like systems.
It is written as a BASH script but does not require you to use BASH as your command shell.
n does not work in native shells on Microsoft Windows (like PowerShell), or Git for Windows BASH, or with the Cygwin DLL.
Installation
If you already have Node.js installed, an easy way to install n is using npm:
npm install -g n
The n command downloads and installs to /usr/local by default, but you may override this location by defining N_PREFIX.
n caches Node.js versions in subdirectory n/versions. The _active_ Node.js version is installed in subdirectories bin, include, lib, and share.
To avoid requiring sudo for n and npm global installs, it is suggested you either install to your home directory using N_PREFIX, or take ownership of the system directories:
# make cache folder (if missing) and take ownership
sudo mkdir -p /usr/local/n
sudo chown -R $(whoami) /usr/local/n
# make sure the required folders exist (safe to execute even if they already exist)
sudo mkdir -p /usr/local/bin /usr/local/lib /usr/local/include /usr/local/share
# take ownership of Node.js install destination folders
sudo chown -R $(whoami) /usr/local/bin /usr/local/lib /usr/local/include /usr/local/share
If npm is not yet available, one way to bootstrap an install:
curl -L https://raw.githubusercontent.com/tj/n/master/bin/n -o n
bash n lts
# Now node and npm are available
npm install -g n
Alternatively, you can clone this repo and
make install
to install n to bin/n of the directory specified in the environment variable $PREFIX, which defaults to /usr/local (note that you will likely need to use sudo). To install n in a custom location (such as $CUSTOM_LOCATION/bin/n), run PREFIX=$CUSTOM_LOCATION make install.
Third Party Installers
brew install n
port install n
On Linux and macOS, n-install allows installation directly from GitHub; for instance:
curl -L https://bit.ly/n-install | bash
n-install sets both PREFIX and N_PREFIX to $HOME/n, installs n to $HOME/n/bin, modifies the initialization files of supported shells to export N_PREFIX and add $HOME/n/bin to the PATH, and installs the latest LTS Node.js version.
As a result, both n itself and all Node.js versions it manages are hosted inside a single, optionally configurable directory, which you can later remove with the included n-uninstall script. n-update updates n itself to the latest version. See the n-install repo for more details.
Installing Node.js Versions
n 10.16.0
n lts
Execute n on its own to view your downloaded versions, and install the selected version.
$ n
node/4.9.1
ο node/8.11.3
node/10.15.0
Use up/down arrow keys to select a version, return key to install, d to delete, q to quit
If the active node version does not change after install, try opening a new shell in case seeing a stale version.
Specifying Node.js Versions
There are a variety of ways of specifying the target Node.js version for n commands. Most commands use the latest matching version, and n ls-remote lists multiple matching versions.
Numeric version numbers can be complete or incomplete, with an optional leading v.
- 4.9.1
- 8: 8.x.y versions
- v6.1: 6.1.x versions
There are labels for two especially useful versions:
- lts: newest Long Term Support official release
- latest, current: newest official release
There is an auto label to read the target version from a file in the current directory, or any parent directory. n looks for in order:
- .n-node-version: version on single line. Custom to n.
- .node-version: version on single line. Used by multiple tools: node-version-usage
- .nvmrc: version on single line. Used by nvm.
- if no version file found, look for engine as below.
The engine label looks for a package.json file and reads the engines field to determine compatible Node.js. Requires an installed version of node, and uses npx semver to resolve complex ranges.
There is support for the named release streams:
- argon, boron, carbon: codenames for LTS release streams
These Node.js support aliases may be used, although simply resolve to the latest matching version:
- active, lts_active, lts_latest, lts, current, supported
The last version form is for specifying other releases available using the name of the remote download folder optionally followed by the complete or incomplete version.
- nightly
- test/v11.0.0-test20180528
- rc/10
Removing Versions
Remove some cached versions:
n rm 0.9.4 v0.10.0
Removing all cached versions except the installed version:
n prune
Remove the installed Node.js (does not affect the cached versions). This can be useful
to revert to the system version of node (if in a different location), or if you no longer
wish to use node and npm, or are switching to a different way of managing them.
n uninstall
Using Downloaded Node.js Versions Without Reinstalling
There are three commands for working directly with your downloaded versions of Node.js, without reinstalling.
You can show the path to the downloaded node version:
$ n which 6.14.3
/usr/local/n/versions/6.14.3/bin/node
Or run a downloaded node version with the n run command:
n run 8.11.3 --debug some.js
Or execute a command with PATH modified so node and npm will be from the downloaded Node.js version.
(NB: npm run this way will be using global node_modules from the target node version folder.)
n exec 10 my-script --fast test
n exec lts zsh
Preserving npm
A Node.js install normally also includes npm, npx, and corepack, but you may wish to preserve your current (especially newer) versions using --preserve:
$ npm install -g npm@latest
...
$ npm --version
6.13.7
# Node.js 8.17.0 includes (older) npm 6.13.4
$ n -p 8
installed : v8.17.0
$ npm --version
6.13.7
You can make this the default by setting the environment variable to a non-empty string. There are separate environment variables for npm and corepack:
export N_PRESERVE_NPM=1
export N_PRESERVE_COREPACK=1
You can be explicit to get the desired behaviour whatever the environment variables:
n --preserve nightly
n --no-preserve latest
Miscellaneous
Command line help can be obtained from n --help.
List matching remote versions available for download:
n ls-remote lts
n ls-remote latest
n lsr 10
n --all lsr
List downloaded versions in cache:
n ls
Display diagnostics to help resolve problems:
n doctor
Custom Source
The most common example is from users in China who can define:
export N_NODE_MIRROR=https://npmmirror.com/mirrors/node
If the custom mirror requires authentication you can add the url-encoded username and password into the URL. e.g.
export N_NODE_MIRROR=https://encoded-username:encoded-password@host:port/path
Custom Architecture
By default n picks the binaries matching your system architecture. For example, on a 64 bit system n will download 64 bit binaries.
On a Mac with Apple silicon:
- for Node.js 16 and higher, n defaults to arm64 binaries which run natively
- for older versions of Node.js, n defaults to x64 binaries which run in Rosetta 2
You can override the default architecture by using the -a or --arch option.
e.g. reinstall latest version of Node.js with x64 binaries:
n rm current
n --arch x64 current
Optional Environment Variables
The n command downloads and installs to /usr/local by default, but you may override this location by defining N_PREFIX.
To change the location to say $HOME/.n, add lines like the following to your shell initialization file:
export N_PREFIX=$HOME/.n
export PATH=$N_PREFIX/bin:$PATH
If you want to store the downloads under a different location, use N_CACHE_PREFIX. This does not affect the currently active
node version.
n defaults to using xz compressed Node.js tarballs for the download if it is likely tar on the system supports xz decompression.
You can override the automatic choice by setting an environment variable to zero or non-zero:
export N_USE_XZ=0 # to disable
export N_USE_XZ=1 # to enable
You can be explicit to get the desired behaviour whatever the environment variable:
n install --use-xz nightly
n install --no-use-xz latest
In brief:
- N_NODE_MIRROR: See Custom source
- N_NODE_DOWNLOAD_MIRROR: See Custom source
- support for NO_COLOR and CLICOLOR=0 for controlling use of ANSI color codes
- N_MAX_REMOTE_MATCHES to change the default ls-remote maximum of 20 matching versions
- N_PRESERVE_NPM: See Preserving npm
- N_PRESERVE_COREPACK: See Preserving npm
How It Works
n downloads a prebuilt Node.js package and installs to a single prefix (e.g. /usr/local). This overwrites the previous version. The bin folder in this location should be in your PATH (e.g. /usr/local/bin).
The downloads are kept in a cache folder to be used for reinstalls. The downloads are also available for limited use using n which and n run and n exec.
The global npm packages are not changed by the install, with the
exception of npm itself which is part of the Node.js install.
