# `n` – Interactively Manage Your Node.js Versions

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Node.js version management: no subshells, no profile setup, no convoluted API, just **simple**.

![usage animation](http://nimit.io/images/n/n.gif)

(Note: `n` is not supported natively on Windows.)

- [`n` – Interactively Manage Your Node.js Versions](#n-%e2%80%93-interactively-manage-your-nodejs-versions)
    - [Installation](#installation)
        - [Third Party Installers](#third-party-installers)
    - [Installing Node Versions](#installing-node-versions)
    - [Specifying Node Versions](#specifying-node-versions)
    - [Removing Versions](#removing-versions)
    - [Using Downloaded Node Versions Without Reinstalling](#using-downloaded-node-versions-without-reinstalling)
    - [Miscellaneous](#miscellaneous)
    - [Custom Source](#custom-source)
    - [Custom Architecture](#custom-architecture)
    - [Optional Environment Variables](#optional-environment-variables)
    - [How It Works](#how-it-works)

## Installation

Since you probably already have `node`, the easiest way to install `n` is through `npm`:

    npm install -g n

Once installed, `n` caches `node` versions in subdirectory `n/versions` of the directory specified in environment variable `N_PREFIX`, which defaults to `/usr/local`; and the _active_ `node` version is installed directly in `N_PREFIX`.

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
    # take ownership of node 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

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

On macOS with [Homebrew](https://brew.sh/) you can install the [n formula](https://github.com/Homebrew/homebrew-core/blob/master/Formula/n.rb).

    brew install n

On Linux and macOS, [n-install](https://github.com/mklement0/n-install) allows installation directly from GitHub; for instance:

    curl -L https://git.io/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` version.

As a result, both `n` itself and all `node` 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](https://github.com/mklement0/n-install) for more details.

## Installing Node Versions

Simply execute `n <version>` to download and install a version of `node`. If `<version>` has already been downloaded, `n` will install from its cache.

    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

(You can also use `j` and `k` to navigate up or down without using arrows.)

If the active node version does not change after install, try opening a new shell in case seeing a stale version.

## Specifying Node Versions

There are a variety of ways of specifying the target node 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 support for release streams:

- `argon`, `boron`, `carbon`: codenames for LTS release streams

The last form is for specifying [other releases](https://nodejs.org/download) available using the name of the remote download folder optionally followed by the complete or incomplete version.

- `chakracore-release/latest`
- `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 current version:

    n prune

Remove the installed node and npm (does not affect the cached version). 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 Versions Without Reinstalling

There are three commands for working directly with your downloaded versions of `node`, without reinstalling.

You can show the path to the downloaded 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` version.
(NB: this `npm` will be working with a different and empty global node_modules directory, and you should not install global
modules this way.)

    n exec 10 my-script --fast test

## 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

If you would like to use a different node mirror which has the same layout as the default <https://nodejs.org/dist/>, you can define `N_NODE_MIRROR`.
The most common example is users in China can define:

    export N_NODE_MIRROR=https://npm.taobao.org/mirrors/node

There is also `N_NODE_DOWNLOAD_MIRROR` for a different mirror with same layout as the default <https://nodejs.org/download>

## Custom Architecture

By default `n` picks the binaries matching your system architecture, e.g. `n` will download 64 bit binaries for a 64 bit system. You can override this by using the `-a` or `--arch` option.

Download and use latest 32 bit version of `node`:

    n --arch x86 latest

## 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

By default `n` downloads archives from the mirror site which have been compressed with `gzip`. You can switch to using the `xz` compressed archives by defining `N_USE_XZ`.

    export N_USE_XZ=true

In brief:

- `N_NODE_MIRROR`: See [Custom source](#custom-source)
- `N_NODE_DOWNLOAD_MIRROR`: See [Custom source](#custom-source)
- support for [NO_COLOR](http://no-color.org) and [CLICOLOR=0](https://bixense.com/clicolors) for controlling use of ANSI color codes
- `N_MAX_REMOTE_MATCHES` to change the default `ls-remote` maximum of 20 matching versions

## How It Works

`n` downloads a prebuilt `node` 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` install.