deps/npm/html/doc/cli/npm-install.html
<!doctype html>
<html>
<title>npm-install</title>
<meta http-equiv="content-type" value="text/html;utf-8">
<link rel="stylesheet" type="text/css" href="../../static/style.css">
<link rel="canonical" href="https://www.npmjs.org/doc/cli/npm-install.html">
<script async=true src="../../static/toc.js"></script>
<body>
<div id="wrapper">
<h1><a href="../cli/npm-install.html">npm-install</a></h1> <p>Install a package</p>
<h2 id="synopsis">SYNOPSIS</h2>
<pre><code>npm install (with no args in a package dir)
npm install <tarball file>
npm install <tarball url>
npm install <folder>
npm install [@<scope>/]<name> [--save|--save-dev|--save-optional] [--save-exact]
npm install [@<scope>/]<name>@<tag>
npm install [@<scope>/]<name>@<version>
npm install [@<scope>/]<name>@<version range>
npm i (with any of the previous argument usage)
</code></pre><h2 id="description">DESCRIPTION</h2>
<p>This command installs a package, and any packages that it depends on. If the
package has a shrinkwrap file, the installation of dependencies will be driven
by that. See <a href="../cli/npm-shrinkwrap.html"><a href="../cli/npm-shrinkwrap.html">npm-shrinkwrap(1)</a></a>.</p>
<p>A <code>package</code> is:</p>
<ul>
<li>a) a folder containing a program described by a package.json file</li>
<li>b) a gzipped tarball containing (a)</li>
<li>c) a url that resolves to (b)</li>
<li>d) a <code><name>@<version></code> that is published on the registry (see <code><a href="../misc/npm-registry.html"><a href="../misc/npm-registry.html">npm-registry(7)</a></a></code>) with (c)</li>
<li>e) a <code><name>@<tag></code> that points to (d)</li>
<li>f) a <code><name></code> that has a "latest" tag satisfying (e)</li>
<li>g) a <code><git remote url></code> that resolves to (b)</li>
</ul>
<p>Even if you never publish your package, you can still get a lot of
benefits of using npm if you just want to write a node program (a), and
perhaps if you also want to be able to easily install it elsewhere
after packing it up into a tarball (b).</p>
<ul>
<li><p><code>npm install</code> (in package directory, no arguments):</p>
<p> Install the dependencies in the local node_modules folder.</p>
<p> In global mode (ie, with <code>-g</code> or <code>--global</code> appended to the command),
it installs the current package context (ie, the current working
directory) as a global package.</p>
<p> By default, <code>npm install</code> will install all modules listed as dependencies.
With the <code>--production</code> flag (or when the <code>NODE_ENV</code> environment variable
is set to <code>production</code>), npm will not install modules listed in
<code>devDependencies</code>.</p>
</li>
<li><p><code>npm install <folder></code>:</p>
<p> Install a package that is sitting in a folder on the filesystem.</p>
</li>
<li><p><code>npm install <tarball file></code>:</p>
<p> Install a package that is sitting on the filesystem. Note: if you just want
to link a dev directory into your npm root, you can do this more easily by
using <code>npm link</code>.</p>
<p> Example:</p>
<pre><code> npm install ./package.tgz
</code></pre></li>
<li><p><code>npm install <tarball url></code>:</p>
<p> Fetch the tarball url, and then install it. In order to distinguish between
this and other options, the argument must start with "http://" or "https://"</p>
<p> Example:</p>
<pre><code> npm install https://github.com/indexzero/forever/tarball/v0.5.6
</code></pre></li>
<li><p><code>npm install [@<scope>/]<name> [--save|--save-dev|--save-optional]</code>:</p>
<p> Do a <code><name>@<tag></code> install, where <code><tag></code> is the "tag" config. (See
<code><a href="../misc/npm-config.html"><a href="../misc/npm-config.html">npm-config(7)</a></a></code>.)</p>
<p> In most cases, this will install the latest version
of the module published on npm.</p>
<p> Example:</p>
<pre><code> npm install sax
</code></pre><p> <code>npm install</code> takes 3 exclusive, optional flags which save or update
the package version in your main package.json:</p>
<ul>
<li><p><code>--save</code>: Package will appear in your <code>dependencies</code>.</p>
</li>
<li><p><code>--save-dev</code>: Package will appear in your <code>devDependencies</code>.</p>
</li>
<li><p><code>--save-optional</code>: Package will appear in your <code>optionalDependencies</code>.</p>
<p>When using any of the above options to save dependencies to your
package.json, there is an additional, optional flag:</p>
</li>
<li><p><code>--save-exact</code>: Saved dependencies will be configured with an
exact version rather than using npm's default semver range
operator.</p>
<p><code><scope></code> is optional. The package will be downloaded from the registry
associated with the specified scope. If no registry is associated with
the given scope the default registry is assumed. See <code><a href="../misc/npm-scope.html"><a href="../misc/npm-scope.html">npm-scope(7)</a></a></code>.</p>
<p>Note: if you do not include the @-symbol on your scope name, npm will
interpret this as a GitHub repository instead, see below. Scopes names
must also be followed by a slash.</p>
<p>Examples:</p>
<pre><code>npm install sax --save
npm install githubname/reponame
npm install @myorg/privatepackage
npm install node-tap --save-dev
npm install dtrace-provider --save-optional
npm install readable-stream --save --save-exact
</code></pre></li>
</ul>
</li>
</ul>
<pre><code>**Note**: If there is a file or folder named `<name>` in the current
working directory, then it will try to install that, and only try to
fetch the package by name if it is not valid.
</code></pre><ul>
<li><p><code>npm install [@<scope>/]<name>@<tag></code>:</p>
<p> Install the version of the package that is referenced by the specified tag.
If the tag does not exist in the registry data for that package, then this
will fail.</p>
<p> Example:</p>
<pre><code> npm install sax@latest
npm install @myorg/mypackage@latest
</code></pre></li>
<li><p><code>npm install [@<scope>/]<name>@<version></code>:</p>
<p> Install the specified version of the package. This will fail if the
version has not been published to the registry.</p>
<p> Example:</p>
<pre><code> npm install sax@0.1.1
npm install @myorg/privatepackage@1.5.0
</code></pre></li>
<li><p><code>npm install [@<scope>/]<name>@<version range></code>:</p>
<p> Install a version of the package matching the specified version range. This
will follow the same rules for resolving dependencies described in <code><a href="../files/package.json.html"><a href="../files/package.json.html">package.json(5)</a></a></code>.</p>
<p> Note that most version ranges must be put in quotes so that your shell will
treat it as a single argument.</p>
<p> Example:</p>
<pre><code> npm install sax@">=0.1.0 <0.2.0"
npm install @myorg/privatepackage@">=0.1.0 <0.2.0"
</code></pre></li>
<li><p><code>npm install <git remote url></code>:</p>
<p> Install a package by cloning a git remote url. The format of the git
url is:</p>
<pre><code> <protocol>://[<user>[:<password>]@]<hostname>[:<port>][:/]<path>[#<commit-ish>]
</code></pre><p> <code><protocol></code> is one of <code>git</code>, <code>git+ssh</code>, <code>git+http</code>, or
<code>git+https</code>. If no <code><commit-ish></code> is specified, then <code>master</code> is
used.</p>
<p> Examples:</p>
<pre><code> git+ssh://git@github.com:npm/npm.git#v1.0.27
git+https://isaacs@github.com/npm/npm.git
git://github.com/npm/npm.git#v1.0.27
</code></pre></li>
<li><p><code>npm install <githubname>/<githubrepo>[#<commit-ish>]</code>:</p>
</li>
<li><p><code>npm install github:<githubname>/<githubrepo>[#<commit-ish>]</code>:</p>
<p> Install the package at <code>https://github.com/githubname/githubrepo</code> by
attempting to clone it using <code>git</code>.</p>
<p> If you don't specify a <em>commit-ish</em> then <code>master</code> will be used.</p>
<p> Examples:</p>
<pre><code> npm install mygithubuser/myproject
npm install github:mygithubuser/myproject
</code></pre></li>
<li><p><code>npm install gist:[<githubname>/]<gistID>[#<commit-ish>]</code>:</p>
<p> Install the package at <code>https://gist.github.com/gistID</code> by attempting to
clone it using <code>git</code>. The GitHub username associated with the gist is
optional and will not be saved in <code>package.json</code> if <code>--save</code> is used.</p>
<p> If you don't specify a <em>commit-ish</em> then <code>master</code> will be used.</p>
<p> Example:</p>
<pre><code> npm install gist:101a11beef
</code></pre></li>
<li><p><code>npm install bitbucket:<bitbucketname>/<bitbucketrepo>[#<commit-ish>]</code>:</p>
<p> Install the package at <code>https://bitbucket.org/bitbucketname/bitbucketrepo</code>
by attempting to clone it using <code>git</code>.</p>
<p> If you don't specify a <em>commit-ish</em> then <code>master</code> will be used.</p>
<p> Example:</p>
<pre><code> npm install bitbucket:mybitbucketuser/myproject
</code></pre></li>
<li><p><code>npm install gitlab:<gitlabname>/<gitlabrepo>[#<commit-ish>]</code>:</p>
<p> Install the package at <code>https://gitlab.com/gitlabname/gitlabrepo</code>
by attempting to clone it using <code>git</code>.</p>
<p> If you don't specify a <em>commit-ish</em> then <code>master</code> will be used.</p>
<p> Example:</p>
<pre><code> npm install gitlab:mygitlabuser/myproject
</code></pre></li>
</ul>
<p>You may combine multiple arguments, and even multiple types of arguments.
For example:</p>
<pre><code>npm install sax@">=0.1.0 <0.2.0" bench supervisor
</code></pre><p>The <code>--tag</code> argument will apply to all of the specified install targets. If a
tag with the given name exists, the tagged version is preferred over newer
versions.</p>
<p>The <code>--force</code> argument will force npm to fetch remote resources even if a
local copy exists on disk.</p>
<pre><code>npm install sax --force
</code></pre><p>The <code>--global</code> argument will cause npm to install the package globally
rather than locally. See <code><a href="../files/npm-folders.html"><a href="../files/npm-folders.html">npm-folders(5)</a></a></code>.</p>
<p>The <code>--link</code> argument will cause npm to link global installs into the
local space in some cases.</p>
<p>The <code>--no-bin-links</code> argument will prevent npm from creating symlinks for
any binaries the package might contain.</p>
<p>The <code>--no-optional</code> argument will prevent optional dependencies from
being installed.</p>
<p>The <code>--no-shrinkwrap</code> argument, which will ignore an available
shrinkwrap file and use the package.json instead.</p>
<p>The <code>--nodedir=/path/to/node/source</code> argument will allow npm to find the
node source code so that npm can compile native modules.</p>
<p>See <code><a href="../misc/npm-config.html"><a href="../misc/npm-config.html">npm-config(7)</a></a></code>. Many of the configuration params have some
effect on installation, since that's most of what npm does.</p>
<h2 id="algorithm">ALGORITHM</h2>
<p>To install a package, npm uses the following algorithm:</p>
<pre><code>install(where, what, family, ancestors)
fetch what, unpack to <where>/node_modules/<what>
for each dep in what.dependencies
resolve dep to precise version
for each dep@version in what.dependencies
not in <where>/node_modules/<what>/node_modules/*
and not in <family>
add precise version deps to <family>
install(<where>/node_modules/<what>, dep, family)
</code></pre><p>For this <code>package{dep}</code> structure: <code>A{B,C}, B{C}, C{D}</code>,
this algorithm produces:</p>
<pre><code>A
+-- B
`-- C
`-- D
</code></pre><p>That is, the dependency from B to C is satisfied by the fact that A
already caused C to be installed at a higher level.</p>
<p>See <a href="../files/npm-folders.html"><a href="../files/npm-folders.html">npm-folders(5)</a></a> for a more detailed description of the specific
folder structures that npm creates.</p>
<h3 id="limitations-of-npm-s-install-algorithm">Limitations of npm's Install Algorithm</h3>
<p>There are some very rare and pathological edge-cases where a cycle can
cause npm to try to install a never-ending tree of packages. Here is
the simplest case:</p>
<pre><code>A -> B -> A' -> B' -> A -> B -> A' -> B' -> A -> ...
</code></pre><p>where <code>A</code> is some version of a package, and <code>A'</code> is a different version
of the same package. Because <code>B</code> depends on a different version of <code>A</code>
than the one that is already in the tree, it must install a separate
copy. The same is true of <code>A'</code>, which must install <code>B'</code>. Because <code>B'</code>
depends on the original version of <code>A</code>, which has been overridden, the
cycle falls into infinite regress.</p>
<p>To avoid this situation, npm flat-out refuses to install any
<code>name@version</code> that is already present anywhere in the tree of package
folder ancestors. A more correct, but more complex, solution would be
to symlink the existing version into the new location. If this ever
affects a real use-case, it will be investigated.</p>
<h2 id="see-also">SEE ALSO</h2>
<ul>
<li><a href="../files/npm-folders.html"><a href="../files/npm-folders.html">npm-folders(5)</a></a></li>
<li><a href="../cli/npm-update.html"><a href="../cli/npm-update.html">npm-update(1)</a></a></li>
<li><a href="../cli/npm-link.html"><a href="../cli/npm-link.html">npm-link(1)</a></a></li>
<li><a href="../cli/npm-rebuild.html"><a href="../cli/npm-rebuild.html">npm-rebuild(1)</a></a></li>
<li><a href="../misc/npm-scripts.html"><a href="../misc/npm-scripts.html">npm-scripts(7)</a></a></li>
<li><a href="../cli/npm-build.html"><a href="../cli/npm-build.html">npm-build(1)</a></a></li>
<li><a href="../cli/npm-config.html"><a href="../cli/npm-config.html">npm-config(1)</a></a></li>
<li><a href="../misc/npm-config.html"><a href="../misc/npm-config.html">npm-config(7)</a></a></li>
<li><a href="../files/npmrc.html"><a href="../files/npmrc.html">npmrc(5)</a></a></li>
<li><a href="../misc/npm-registry.html"><a href="../misc/npm-registry.html">npm-registry(7)</a></a></li>
<li><a href="../cli/npm-tag.html"><a href="../cli/npm-tag.html">npm-tag(1)</a></a></li>
<li><a href="../cli/npm-rm.html"><a href="../cli/npm-rm.html">npm-rm(1)</a></a></li>
<li><a href="../cli/npm-shrinkwrap.html"><a href="../cli/npm-shrinkwrap.html">npm-shrinkwrap(1)</a></a></li>
</ul>
</div>
<table border=0 cellspacing=0 cellpadding=0 id=npmlogo>
<tr><td style="width:180px;height:10px;background:rgb(237,127,127)" colspan=18> </td></tr>
<tr><td rowspan=4 style="width:10px;height:10px;background:rgb(237,127,127)"> </td><td style="width:40px;height:10px;background:#fff" colspan=4> </td><td style="width:10px;height:10px;background:rgb(237,127,127)" rowspan=4> </td><td style="width:40px;height:10px;background:#fff" colspan=4> </td><td rowspan=4 style="width:10px;height:10px;background:rgb(237,127,127)"> </td><td colspan=6 style="width:60px;height:10px;background:#fff"> </td><td style="width:10px;height:10px;background:rgb(237,127,127)" rowspan=4> </td></tr>
<tr><td colspan=2 style="width:20px;height:30px;background:#fff" rowspan=3> </td><td style="width:10px;height:10px;background:rgb(237,127,127)" rowspan=3> </td><td style="width:10px;height:10px;background:#fff" rowspan=3> </td><td style="width:20px;height:10px;background:#fff" rowspan=4 colspan=2> </td><td style="width:10px;height:20px;background:rgb(237,127,127)" rowspan=2> </td><td style="width:10px;height:10px;background:#fff" rowspan=3> </td><td style="width:20px;height:10px;background:#fff" rowspan=3 colspan=2> </td><td style="width:10px;height:10px;background:rgb(237,127,127)" rowspan=3> </td><td style="width:10px;height:10px;background:#fff" rowspan=3> </td><td style="width:10px;height:10px;background:rgb(237,127,127)" rowspan=3> </td></tr>
<tr><td style="width:10px;height:10px;background:#fff" rowspan=2> </td></tr>
<tr><td style="width:10px;height:10px;background:#fff"> </td></tr>
<tr><td style="width:60px;height:10px;background:rgb(237,127,127)" colspan=6> </td><td colspan=10 style="width:10px;height:10px;background:rgb(237,127,127)"> </td></tr>
<tr><td colspan=5 style="width:50px;height:10px;background:#fff"> </td><td style="width:40px;height:10px;background:rgb(237,127,127)" colspan=4> </td><td style="width:90px;height:10px;background:#fff" colspan=9> </td></tr>
</table>
<p id="footer">npm-install — npm@2.11.3</p>