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<!DOCTYPE html>
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<title>Filer</title>
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<a id="forkme_banner" href="https://github.com/filerjs/filer">View on GitHub</a>
<h1 id="project_title">Filer</h1>
<h2 id="project_tagline">Node-like file system for browsers</h2>
<section id="downloads">
<a class="zip_download_link" href="https://github.com/filerjs/filer/zipball/master">Download this project as a .zip file</a>
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<p><a href="https://nodei.co/npm/filer/"><img src="https://nodei.co/npm/filer.png?downloads=true&amp;stars=true" alt="NPM"></a></p>
<p><a href="http://travis-ci.org/filerjs/filer"><img src="https://secure.travis-ci.org/filerjs/filer.png?branch=develop" alt="Build Status"></a></p>
<h3>
<a id="filer" class="anchor" href="#filer" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer</h3>
<p>Filer is a POSIX-like file system interface for node.js and browser-based JavaScript.</p>
<h3>
<a id="compatibility" class="anchor" href="#compatibility" aria-hidden="true"><span class="octicon octicon-link"></span></a>Compatibility</h3>
<p>Filer is known to work in the following browsers/versions, with the specified <a href="#providers">Storage Providers</a>:</p>
<ul>
<li>node.js: v0.10.*+</li>
<li>IE: 10+ (IndexedDB)</li>
<li>Firefox: 26+ (IndexedDB)</li>
<li>Chrome: 31+ (IndexedDB, WebSQL)</li>
<li>Safari: 7.0+ (WebSQL)</li>
<li>Opera: 19+ (IndexedDB, WebSQL)</li>
<li>iOS: 3.2+ (WebSQL)</li>
<li>Android Browser: 2.1-4.4 (WebSQL), 4.4+ (IndexedDB)</li>
</ul>
<p>NOTE: if you're interested in maximum compatibility, use the <code>Fallback</code> provider instead of <code>Default</code>.
See the section on <a href="#providers">Storage Providers</a>.</p>
<h3>
<a id="contributing" class="anchor" href="#contributing" aria-hidden="true"><span class="octicon octicon-link"></span></a>Contributing</h3>
<p>Want to join the fun? We'd love to have you! See <a href="https://github.com/filerjs/filer/blob/develop/CONTRIBUTING.md">CONTRIBUTING</a>.</p>
<h3>
<a id="how-to-get-it" class="anchor" href="#how-to-get-it" aria-hidden="true"><span class="octicon octicon-link"></span></a>How to Get It</h3>
<p>Filer can be obtained in a number of ways:</p>
<ol>
<li>npm - <code>npm install filer</code>
</li>
<li>bower - <code>bower install filer</code>
</li>
<li>download pre-built versions: <a href="https://raw.github.com/filerjs/filer/develop/dist/filer.js">filer.js</a>, <a href="https://raw.github.com/filerjs/filer/develop/dist/filer.min.js">filer.min.js</a>
</li>
</ol>
<h3>
<a id="loading-and-usage" class="anchor" href="#loading-and-usage" aria-hidden="true"><span class="octicon octicon-link"></span></a>Loading and Usage</h3>
<p>Filer is built as a UMD module and can therefore be loaded as a CommonJS or AMD module, or used via the global.</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Option 1: Filer loaded via require() in node/browserify</span>
<span class="pl-s">var</span> Filer <span class="pl-k">=</span> <span class="pl-s3">require</span>(<span class="pl-s1"><span class="pl-pds">'</span>filer<span class="pl-pds">'</span></span>);
<span class="pl-c">// Option 2: Filer loaded via RequireJS</span>
requirejs.config({
baseUrl<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>/<span class="pl-pds">'</span></span>,
paths<span class="pl-k">:</span> {
<span class="pl-s1"><span class="pl-pds">'</span>filer<span class="pl-pds">'</span></span><span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>filer/dist/filer<span class="pl-pds">'</span></span>
}
});
requirejs([<span class="pl-s1"><span class="pl-pds">'</span>filer<span class="pl-pds">'</span></span>], <span class="pl-st">function</span>(<span class="pl-vpf">Filer</span>) {...}
<span class="pl-c">// Option 3: Filer on global</span>
<span class="pl-s">var</span> Filer <span class="pl-k">=</span> <span class="pl-s3">window</span>.Filer;</pre></div>
<h3>
<a id="getting-started" class="anchor" href="#getting-started" aria-hidden="true"><span class="octicon octicon-link"></span></a>Getting Started</h3>
<p>Filer is as close to the node.js <a href="http://nodejs.org/api/fs.html">fs module</a> as possible,
with the following differences:</p>
<ul>
<li>No synchronous versions of methods (e.g., <code>mkdir()</code> but not <code>mkdirSync()</code>).</li>
<li>No permissions (e.g., no <code>chown()</code>, <code>chmod()</code>, etc.).</li>
<li>No support for stream-based operations (e.g., <code>fs.ReadStream</code>, <code>fs.WriteStream</code>).</li>
</ul>
<p>Filer has other features lacking in node.js (e.g., swappable backend
storage providers, extended attributes, etc).</p>
<p>Like node.js, the API is asynchronous and most methods expect the caller to provide
a callback function (note: like node.js, Filer will supply one if it's missing).
Errors are passed to callbacks through the first parameter. As with node.js,
there is no guarantee that file system operations will be executed in the order
they are invoked. Ensure proper ordering by chaining operations in callbacks.</p>
<h3>
<a id="overview" class="anchor" href="#overview" aria-hidden="true"><span class="octicon octicon-link"></span></a>Overview</h3>
<p>To create a new file system or open an existing one, create a new <code>FileSystem</code>
instance. By default, a new <a href="https://developer.mozilla.org/en/docs/IndexedDB">IndexedDB</a>
database is created for each file system. The file system can also use other
backend storage providers, for example <a href="http://en.wikipedia.org/wiki/Web_SQL_Database">WebSQL</a>
or even RAM (i.e., for temporary storage). See the section on <a href="#providers">Storage Providers</a>.</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w+<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
fs.<span class="pl-s3">close</span>(fd, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
fs.stat(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
<span class="pl-en">console</span><span class="pl-s3">.log</span>(<span class="pl-s1"><span class="pl-pds">'</span>stats: <span class="pl-pds">'</span></span> <span class="pl-k">+</span> JSON.stringify(stats));
});
});
});</pre></div>
<p>For a complete list of <code>FileSystem</code> methods and examples, see the <a href="#FileSystemMethods">FileSystem Instance Methods</a>
section below.</p>
<p>Filer also supports node's Path module. See the <a href="#FilerPath">Filer.Path</a> section below.</p>
<p>In addition, common shell operations (e.g., rm, touch, cat, etc.) are supported via the
<code>FileSystemShell</code> object, which can be obtained from, and used with a <code>FileSystem</code>.
See the<a href="#FileSystemShell">FileSystemShell</a> section below.</p>
<h3>
<a id="api-reference" class="anchor" href="#api-reference" aria-hidden="true"><span class="octicon octicon-link"></span></a>API Reference</h3>
<p>Like node.js, callbacks for methods that accept them are optional but suggested (i.e., if
you omit the callback, errors will be thrown as exceptions). The first callback parameter is
reserved for passing errors. It will be <code>null</code> if no errors occurred and should always be checked.</p>
<h4>
<a id="filerfilesystemoptions-callback-constructor" class="anchor" href="#filerfilesystemoptions-callback-constructor" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer.FileSystem(options, callback) constructor</h4>
<p>File system constructor, invoked to open an existing file system or create a new one.
Accepts two arguments: an <code>options</code> object, and an optional <code>callback</code>. The <code>options</code>
object can specify a number of optional arguments, including:</p>
<ul>
<li>
<code>name</code>: the name of the file system, defaults to <code>'"local'</code>
</li>
<li>
<code>flags</code>: an Array of one or more flags to use when creating/opening the file system:
<ul>
<li>
<code>'FORMAT'</code> to force Filer to format (i.e., erase) the file system</li>
<li>
<code>'NOCTIME'</code> to force Filer to not update <code>ctime</code> on nodes when metadata changes (i.e., for better performance)</li>
<li>
<code>'NOMTIME'</code> to force Filer to not update <code>mtime</code> on nodes when data changes (i.e., for better performance)</li>
</ul>
</li>
<li>
<code>provider</code>: an explicit storage provider to use for the file system's database context provider. See the section on <a href="#providers">Storage Providers</a>.</li>
</ul>
<p>The <code>callback</code> function indicates when the file system is ready for use. Depending on the storage provider used, this might
be right away, or could take some time. The callback should expect two arguments: first, an <code>error</code> argument, which will be
null if everything worked; second, an instance, such that you can access the newly ready FileSystem instance. Also users
should check the file system's <code>readyState</code> and <code>error</code> properties to make sure it is usable.</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs;
<span class="pl-st">function</span> <span class="pl-en">fsReady</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fs</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Safe to use fs now...</span>
}
fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>({
name<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">"</span>my-filesystem<span class="pl-pds">"</span></span>,
flags<span class="pl-k">:</span> [ <span class="pl-s1"><span class="pl-pds">'</span>FORMAT<span class="pl-pds">'</span></span> ],
provider<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>.providers.Memory()
}, fsReady);</pre></div>
<p>NOTE: if the optional callback argument is not passed to the <code>FileSystem</code> constructor,
operations done on the resulting file system will be queued and run in sequence when
it becomes ready.</p>
<h4>
<a id="filerfilesystemproviders---storage-providers" class="anchor" href="#filerfilesystemproviders---storage-providers" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer.FileSystem.providers - Storage Providers<a name="providers"></a>
</h4>
<p>Filer can be configured to use a number of different storage providers. The provider object encapsulates all aspects
of data access, making it possible to swap in different backend storage options. There are currently 4 different
providers to choose from:</p>
<ul>
<li>
<code>FileSystem.providers.IndexedDB()</code> - uses IndexedDB</li>
<li>
<code>FileSystem.providers.WebSQL()</code> - uses WebSQL</li>
<li>
<code>FileSystem.providers.Fallback()</code> - attempts to use IndexedDB if possible, falling-back to WebSQL if necessary</li>
<li>
<code>FileSystem.providers.Memory()</code> - uses memory (not suitable for data that needs to survive the current session)</li>
</ul>
<p>You can choose your provider when creating a <code>FileSystem</code>:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> FileSystem <span class="pl-k">=</span> Filer.FileSystem;
<span class="pl-s">var</span> providers <span class="pl-k">=</span> FileSystem.providers;
<span class="pl-c">// Example 1: Use the default provider (currently IndexedDB)</span>
<span class="pl-s">var</span> fs1 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">FileSystem</span>();
<span class="pl-c">// Example 2: Explicitly use IndexedDB</span>
<span class="pl-s">var</span> fs2 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">FileSystem</span>({ provider<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-en">providers.IndexedDB</span>() });
<span class="pl-c">// Example 3: Use one of IndexedDB or WebSQL, whichever is supported</span>
<span class="pl-s">var</span> fs3 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">FileSystem</span>({ provider<span class="pl-k">:</span> <span class="pl-k">new</span> <span class="pl-en">providers.Fallback</span>() });</pre></div>
<p>Every provider has an <code>isSupported()</code> method, which returns <code>true</code> if the browser supports this provider:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-k">if</span>( Filer.FileSystem.providers.WebSQL.isSupported() ) {
<span class="pl-c">// WebSQL provider will work in current environment...</span>
}</pre></div>
<p>You can also write your own provider if you need a different backend. See the code in <code>src/providers</code> for details.</p>
<p>A number of other providers have been written, including:</p>
<ul>
<li>node.js fs provider: <a href="https://github.com/humphd/filer-fs">https://github.com/humphd/filer-fs</a>
</li>
<li>node.js Amazon S3 provider: <a href="https://github.com/alicoding/filer-s3">https://github.com/alicoding/filer-s3</a>
</li>
</ul>
<h4>
<a id="filerbuffer" class="anchor" href="#filerbuffer" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer.Buffer<a name="FilerBuffer"></a>
</h4>
<p>When reading and writing data, Filer follows node.js and uses <a href="http://nodejs.org/api/buffer.html"><code>Buffer</code></a>.
When in a node.js environment, native <code>Buffer</code>s can be used, or Filer.Buffer, which is a shortcut
to node's <code>Buffer</code>. In a browser, you can use also use <code>Filer.Buffer</code>.</p>
<p>NOTE: a <code>Filer.Buffer</code> in a browser is really an augmented <code>Uint8Array</code> (i.e., the node <code>Buffer</code> api
methods are added to the instance). See <a href="https://github.com/feross/buffer">https://github.com/feross/buffer</a> for more details. Additionally, unlike native <code>Buffer</code>, <code>Filer.Buffer</code>'s constructor can accept <code>ArrayBuffer</code> objects, which will be interpreted as <code>Uint8Array</code>s.</p>
<h4>
<a id="filerpath" class="anchor" href="#filerpath" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer.Path<a name="FilerPath"></a>
</h4>
<p>The node.js <a href="http://nodejs.org/api/path.html">path module</a> is available via the <code>Filer.Path</code> object. It is
identical to the node.js version with the following differences:</p>
<ul>
<li>No notion of a current working directory in <code>resolve</code> (the root dir is used instead)</li>
</ul>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> path <span class="pl-k">=</span> Filer.Path;
<span class="pl-s">var</span> dir <span class="pl-k">=</span> path.dirname(<span class="pl-s1"><span class="pl-pds">'</span>/foo/bar/baz/asdf/quux<span class="pl-pds">'</span></span>);
<span class="pl-c">// dir is now '/foo/bar/baz/asdf'</span>
<span class="pl-s">var</span> base <span class="pl-k">=</span> path.basename(<span class="pl-s1"><span class="pl-pds">'</span>/foo/bar/baz/asdf/quux.html<span class="pl-pds">'</span></span>);
<span class="pl-c">// base is now 'quux.html'</span>
<span class="pl-s">var</span> ext <span class="pl-k">=</span> path.extname(<span class="pl-s1"><span class="pl-pds">'</span>index.html<span class="pl-pds">'</span></span>);
<span class="pl-c">// ext is now '.html'</span>
<span class="pl-s">var</span> newpath <span class="pl-k">=</span> path.<span class="pl-s3">join</span>(<span class="pl-s1"><span class="pl-pds">'</span>/foo<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>bar<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>baz/asdf<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>quux<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>..<span class="pl-pds">'</span></span>);
<span class="pl-c">// new path is now '/foo/bar/baz/asdf'</span></pre></div>
<p>For more info see the docs in the <a href="http://nodejs.org/api/path.html">path module</a> for a particular method:</p>
<ul>
<li><code>path.normalize(p)</code></li>
<li><code>path.join([path1], [path2], [...])</code></li>
<li><code>path.resolve([from ...], to)</code></li>
<li><code>path.relative(from, to)</code></li>
<li><code>path.dirname(p)</code></li>
<li><code>path.basename(p, [ext])</code></li>
<li><code>path.extname(p)</code></li>
<li><code>path.sep</code></li>
<li><code>path.delimiter</code></li>
</ul>
<h4>
<a id="filererrors" class="anchor" href="#filererrors" aria-hidden="true"><span class="octicon octicon-link"></span></a>Filer.Errors<a name="Errors"></a>
</h4>
<p>The error objects used internally by Filer are also exposed via the <code>Filer.Errors</code> object. As much as possible
these match their node.js counterparts, with a few Filer-specifc additions.
See <a href="https://github.com/filerjs/filer/blob/develop/src/errors.js">src/errors.js</a> for the complete
list. Errors can be used, or compared, like so:</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Example 1: create an EExist error</span>
<span class="pl-s">var</span> err1 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Errors</span>.EEXIST();
<span class="pl-s">var</span> err2 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Errors</span>[<span class="pl-c1">47</span>];
<span class="pl-c">// Example 2: compare an error to see if it is EInvalid</span>
<span class="pl-st">function</span> <span class="pl-en">callback</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err <span class="pl-k">instanceof</span> Filer.Errors.EINVAL){
...
}
<span class="pl-c">// Or compare the error's code</span>
<span class="pl-k">if</span>(err.<span class="pl-sc">code</span> <span class="pl-k">===</span> <span class="pl-s1"><span class="pl-pds">'</span>EINVAL<span class="pl-pds">'</span></span>) {
...
}
}
<span class="pl-c">// Example 4: compare an error using errno</span>
<span class="pl-st">function</span> <span class="pl-en">callback</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err.errno <span class="pl-k">===</span> <span class="pl-c1">47</span>){
...
}
<span class="pl-c">// Example 5: display the error message</span>
<span class="pl-en">console</span><span class="pl-s3">.log</span>(err.message);</pre></div>
<h3>
<a id="filesystem-instance-methods" class="anchor" href="#filesystem-instance-methods" aria-hidden="true"><span class="octicon octicon-link"></span></a>FileSystem Instance Methods<a name="FileSystemMethods"></a>
</h3>
<p>Once a <code>FileSystem</code> is created, it has the following methods. NOTE: code examples below assume
a <code>FileSystem</code> instance named <code>fs</code> has been created like so:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();</pre></div>
<ul>
<li><a href="#rename">fs.rename(oldPath, newPath, callback)</a></li>
<li><a href="#ftruncate">fs.ftruncate(fd, len, callback)</a></li>
<li><a href="#truncate">fs.truncate(path, len, callback)</a></li>
<li><a href="#stat">fs.stat(path, callback)</a></li>
<li><a href="#fstat">fs.fstat(fd, callback)</a></li>
<li><a href="#lstat">fs.lstat(path, callback)</a></li>
<li><a href="#exists">fs.exists(path, callback)</a></li>
<li><a href="#link">fs.link(srcpath, dstpath, callback)</a></li>
<li><a href="#symlink">fs.symlink(srcpath, dstpath, [type], callback)</a></li>
<li><a href="#readlink">fs.readlink(path, callback)</a></li>
<li><a href="#realpath">fs.realpath(path, [cache], callback)</a></li>
<li><a href="#unlink">fs.unlink(path, callback)</a></li>
<li><a href="#mknod">fs.mknod(path, mode, callback)</a></li>
<li><a href="#rmdir">fs.rmdir(path, callback)</a></li>
<li><a href="#mkdir">fs.mkdir(path, [mode], callback)</a></li>
<li><a href="#readdir">fs.readdir(path, callback)</a></li>
<li><a href="#close">fs.close(fd, callback)</a></li>
<li><a href="#open">fs.open(path, flags, [mode], callback)</a></li>
<li><a href="#utimes">fs.utimes(path, atime, mtime, callback)</a></li>
<li><a href="#fsutimes">fs.futimes(fd, atime, mtime, callback)</a></li>
<li><a href="#fsync">fs.fsync(fd, callback)</a></li>
<li><a href="#write">fs.write(fd, buffer, offset, length, position, callback)</a></li>
<li><a href="#read">fs.read(fd, buffer, offset, length, position, callback)</a></li>
<li><a href="#readFile">fs.readFile(filename, [options], callback)</a></li>
<li><a href="#writeFile">fs.writeFile(filename, data, [options], callback)</a></li>
<li><a href="#appendFile">fs.appendFile(filename, data, [options], callback)</a></li>
<li><a href="#setxattr">fs.setxattr(path, name, value, [flag], callback)</a></li>
<li><a href="#fsetxattr">fs.fsetxattr(fd, name, value, [flag], callback)</a></li>
<li><a href="#getxattr">fs.getxattr(path, name, callback)</a></li>
<li><a href="#fgetxattr">fs.fgetxattr(fd, name, callback)</a></li>
<li><a href="#removexattr">fs.removexattr(path, name, callback)</a></li>
<li><a href="#fremovexattr">fs.fremovexattr(fd, name, callback)</a></li>
<li><a href="#watch">fs.watch(filename, [options], [listener])</a></li>
</ul>
<h4>
<a id="fsrenameoldpath-newpath-callback" class="anchor" href="#fsrenameoldpath-newpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.rename(oldPath, newPath, callback)<a name="rename"></a>
</h4>
<p>Renames the file at <code>oldPath</code> to <code>newPath</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/rename.html">rename(2)</a>.
Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Rename myfile.txt to myfile.bak</span>
fs.rename(<span class="pl-s1"><span class="pl-pds">"</span>/myfile.txt<span class="pl-pds">"</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>/myfile.bak<span class="pl-pds">"</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// myfile.txt is now myfile.bak</span>
});</pre></div>
<h4>
<a id="fsftruncatefd-len-callback" class="anchor" href="#fsftruncatefd-len-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.ftruncate(fd, len, callback)<a name="ftruncate"></a>
</h4>
<p>Change the size of the file represented by the open file descriptor <code>fd</code> to be length
<code>len</code> bytes. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/ftruncate.html">ftruncate(2)</a>.
If the file is larger than <code>len</code>, the extra bytes will be discarded; if smaller, its size will
be increased, and the extended area will appear as if it were zero-filled. See also <a href="#truncate">fs.truncate()</a>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create a file, shrink it, expand it.</span>
<span class="pl-s">var</span> buffer <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>, <span class="pl-c1">4</span>, <span class="pl-c1">5</span>, <span class="pl-c1">6</span>, <span class="pl-c1">7</span>, <span class="pl-c1">8</span>]);
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
fs.<span class="pl-s3">write</span>(fd, buffer, <span class="pl-c1">0</span>, buffer.<span class="pl-sc">length</span>, <span class="pl-c1">0</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">result</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
fs.ftruncate(fd, <span class="pl-c1">3</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// /myfile is now 3 bytes in length, rest of data discarded</span>
fs.ftruncate(fd, <span class="pl-c1">50</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// /myfile is now 50 bytes in length, with zero padding at end</span>
fs.<span class="pl-s3">close</span>(fd);
});
});
});
});
});</pre></div>
<h4>
<a id="fstruncatepath-len-callback" class="anchor" href="#fstruncatepath-len-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.truncate(path, len, callback)<a name="truncate"></a>
</h4>
<p>Change the size of the file at <code>path</code> to be length <code>len</code> bytes. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/truncate.html">truncate(2)</a>. If the file is larger than <code>len</code>, the extra bytes will be discarded; if smaller, its size will
be increased, and the extended area will appear as if it were zero-filled. See also <a href="#ftruncate">fs.ftruncate()</a>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create a file, shrink it, expand it.</span>
<span class="pl-s">var</span> buffer <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>, <span class="pl-c1">4</span>, <span class="pl-c1">5</span>, <span class="pl-c1">6</span>, <span class="pl-c1">7</span>, <span class="pl-c1">8</span>]);
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
fs.<span class="pl-s3">write</span>(fd, buffer, <span class="pl-c1">0</span>, buffer.<span class="pl-sc">length</span>, <span class="pl-c1">0</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">result</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
fs.<span class="pl-s3">close</span>(fd, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
fs.truncate(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-c1">3</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// /myfile is now 3 bytes in length, rest of data discarded</span>
fs.truncate(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-c1">50</span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// /myfile is now 50 bytes in length, with zero padding at end</span>
});
});
});
});
});</pre></div>
<h4>
<a id="fsstatpath-callback" class="anchor" href="#fsstatpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.stat(path, callback)<a name="stat"></a>
</h4>
<p>Obtain file status about the file at <code>path</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/stat.html">stat(2)</a>.
Callback gets <code>(error, stats)</code>, where <code>stats</code> is an object with the following properties:</p>
<pre><code>{
node: &lt;string&gt; // internal node id (unique)
dev: &lt;string&gt; // file system name
size: &lt;number&gt; // file size in bytes
nlinks: &lt;number&gt; // number of links
atime: &lt;number&gt; // last access time
mtime: &lt;number&gt; // last modified time
ctime: &lt;number&gt; // creation time
type: &lt;string&gt; // file type (FILE, DIRECTORY, SYMLINK)
}
</code></pre>
<p>The following convenience methods are also present on the callback's <code>stats</code>:</p>
<pre><code>isFile(): Returns true if the node is a file.
isDirectory(): Returns true if the node is a directory.
isBlockDevice(): Not implemented, returns false.
isCharacterDevice(): Not implemented, returns false.
isSymbolicLink(): Returns true if the node is a symbolic link.
isFIFO(): Not implemented, returns false.
isSocket(): Not implemented, returns false.
</code></pre>
<p>If the file at <code>path</code> is a symbolic link, the file to which it links will be used instead.
To get the status of a symbolic link file, use <a href="#lstat">fs.lstat()</a> instead.</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Check if a directory exists</span>
<span class="pl-st">function</span> <span class="pl-en">dirExists</span>(<span class="pl-vpf">path</span>, <span class="pl-vpf">callback</span>) {
fs.stat(path, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">return</span> callback(err);
<span class="pl-s">var</span> exists <span class="pl-k">=</span> stats.<span class="pl-sc">type</span> <span class="pl-k">===</span> <span class="pl-s1"><span class="pl-pds">"</span>DIRECTORY<span class="pl-pds">"</span></span>;
callback(<span class="pl-c1">null</span>, exists);
});
};
<span class="pl-c">// Get the size of a file in KB</span>
<span class="pl-st">function</span> <span class="pl-en">fileSize</span>(<span class="pl-vpf">path</span>, <span class="pl-vpf">callback</span>) {
fs.stat(path, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">return</span> callback(err);
<span class="pl-s">var</span> kb <span class="pl-k">=</span> stats.<span class="pl-sc">size</span> / <span class="pl-c1">1000</span>;
callback(<span class="pl-c1">null</span>, kb);
});
}</pre></div>
<h4>
<a id="fsfstatfd-callback" class="anchor" href="#fsfstatfd-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.fstat(fd, callback)<a name="fstat"></a>
</h4>
<p>Obtain information about the open file known by the file descriptor <code>fd</code>.
Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/fstat.html">fstat(2)</a>.
Callback gets <code>(error, stats)</code>. <code>fstat()</code> is identical to <code>stat()</code>, except that the file to be stat-ed is
specified by the open file descriptor <code>fd</code> instead of a path. See also <a href="#stat">fs.stat</a></p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">"</span>/file.txt<span class="pl-pds">"</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>r<span class="pl-pds">"</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.fstat(fd, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// do something with stats object</span>
<span class="pl-c">// ...</span>
fs.<span class="pl-s3">close</span>(fd);
});
});</pre></div>
<h4>
<a id="fslstatpath-callback" class="anchor" href="#fslstatpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.lstat(path, callback)<a name="lstat"></a>
</h4>
<p>Obtain information about the file at <code>path</code> (i.e., the symbolic link file itself) vs.
the destination file to which it links. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/lstat.html">lstat(2)</a>.
Callback gets <code>(error, stats)</code>. See also <a href="#stat">fs.stat</a>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create a symbolic link, /data/logs/current to /data/logs/august</span>
<span class="pl-c">// and get info about the symbolic link file, and linked file.</span>
fs.<span class="pl-s3">link</span>(<span class="pl-s1"><span class="pl-pds">"</span>/data/logs/august<span class="pl-pds">"</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>/data/logs/current<span class="pl-pds">"</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Get status of linked file, /data/logs/august</span>
fs.stat(<span class="pl-s1"><span class="pl-pds">"</span>/data/logs/current<span class="pl-pds">"</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Size of /data/logs/august</span>
<span class="pl-s">var</span> size <span class="pl-k">=</span> stats.<span class="pl-sc">size</span>;
});
<span class="pl-c">// Get status of symbolic link file itself</span>
fs.lstat(<span class="pl-s1"><span class="pl-pds">"</span>/data/logs/current<span class="pl-pds">"</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Size of /data/logs/current</span>
<span class="pl-s">var</span> size <span class="pl-k">=</span> stats.<span class="pl-sc">size</span>;
});
});</pre></div>
<h4>
<a id="fsexistspath-callback" class="anchor" href="#fsexistspath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.exists(path, callback)<a name="exists"></a>
</h4>
<p>Test whether or not the given path exists by checking with the file system.
Then call the callback argument with either true or false.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">//Test if the file exists</span>
fs.exists(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">exists</span>) {
<span class="pl-en">console</span><span class="pl-s3">.log</span>(exists <span class="pl-k">?</span> <span class="pl-s1"><span class="pl-pds">"</span>file exists<span class="pl-pds">"</span></span> <span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">"</span>file not found<span class="pl-pds">"</span></span>);
});</pre></div>
<p>fs.exists() is an anachronism and exists only for historical reasons. There should almost never be a reason to use it in your own code.</p>
<p>In particular, checking if a file exists before opening it is an anti-pattern that leaves you vulnerable to race conditions: another process may remove the file between the calls to fs.exists() and fs.open(). Just open the file and handle the error when it's not there.</p>
<h4>
<a id="fslinksrcpath-dstpath-callback" class="anchor" href="#fslinksrcpath-dstpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.link(srcPath, dstPath, callback)<a name="link"></a>
</h4>
<p>Create a (hard) link to the file at <code>srcPath</code> named <code>dstPath</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/link.html">link(2)</a>. Callback gets no additional arguments. Links are directory entries that point to the same file node.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">link</span>(<span class="pl-s1"><span class="pl-pds">'</span>/logs/august.log<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.readFile(<span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>utf8<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">data</span>) {
<span class="pl-c">// data is the contents of /logs/august.log</span>
<span class="pl-s">var</span> currentLog <span class="pl-k">=</span> data;
});
});</pre></div>
<h4>
<a id="fssymlinksrcpath-dstpath-type-callback" class="anchor" href="#fssymlinksrcpath-dstpath-type-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.symlink(srcPath, dstPath, [type], callback)<a name="symlink"></a>
</h4>
<p>Create a symbolic link to the file at <code>dstPath</code> containing the path <code>srcPath</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/symlink.html">symlink(2)</a>. Callback gets no additional arguments.
Symbolic links are files that point to other paths.</p>
<p>NOTE: Filer allows for, but ignores the optional <code>type</code> parameter used in node.js.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.symlink(<span class="pl-s1"><span class="pl-pds">'</span>/logs/august.log<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.readFile(<span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>utf8<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">data</span>) {
<span class="pl-c">// data is the contents of /logs/august.log</span>
<span class="pl-s">var</span> currentLog <span class="pl-k">=</span> data;
});
});</pre></div>
<h4>
<a id="fsreadlinkpath-callback" class="anchor" href="#fsreadlinkpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.readlink(path, callback)<a name="readlink"></a>
</h4>
<p>Reads the contents of a symbolic link. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/readlink.html">readlink(2)</a>. Callback gets <code>(error, linkContents)</code>, where <code>linkContents</code> is a string containing the symbolic link's link path.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.symlink(<span class="pl-s1"><span class="pl-pds">'</span>/logs/august.log<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">error</span>) {
<span class="pl-k">if</span>(error) <span class="pl-k">throw</span> error;
fs.readlink(<span class="pl-s1"><span class="pl-pds">'</span>/logs/current<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">error</span>, <span class="pl-vpf">linkContents</span>) {
<span class="pl-c">// linkContents is now '/logs/august.log'</span>
});
});</pre></div>
<h4>
<a id="fsrealpathpath-cache-callback" class="anchor" href="#fsrealpathpath-cache-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.realpath(path, [cache], callback)<a name="realpath"></a>
</h4>
<p>NOTE: Not implemented, see <a href="https://github.com/filerjs/filer/issues/85">https://github.com/filerjs/filer/issues/85</a></p>
<h4>
<a id="fsunlinkpath-callback" class="anchor" href="#fsunlinkpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.unlink(path, callback)<a name="unlink"></a>
</h4>
<p>Removes the directory entry located at <code>path</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/unlink.html">unlink(2)</a>.
Callback gets no additional arguments. If <code>path</code> names a symbolic link, the symbolic link will be removed
(i.e., not the linked file). Otherwise, the filed named by <code>path</code> will be removed (i.e., deleted).</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Delete regular file /backup.old</span>
fs.unlink(<span class="pl-s1"><span class="pl-pds">'</span>/backup.old<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /backup.old is now removed</span>
});</pre></div>
<h4>
<a id="fsmknodpath-mode-callback" class="anchor" href="#fsmknodpath-mode-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.mknod(path, mode, callback)<a name="mknod"></a>
</h4>
<p>Creates a node at <code>path</code> based on the mode passed which is either <code>FILE</code> or <code>DIRECTORY</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/mknod.html">mknod(2)</a>. Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create a /dir directory</span>
fs.mknod(<span class="pl-s1"><span class="pl-pds">'</span>/dir<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>DIRECTORY<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /dir is now created</span>
<span class="pl-c">// Create a file inside /dir</span>
fs.mknod(<span class="pl-s1"><span class="pl-pds">'</span>/dir/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>FILE<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /dir/myfile now exists</span>
});
});</pre></div>
<h4>
<a id="fsrmdirpath-callback" class="anchor" href="#fsrmdirpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.rmdir(path, callback)<a name="rmdir"></a>
</h4>
<p>Removes the directory at <code>path</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/rmdir.html">rmdir(2)</a>.
Callback gets no additional arguments. The operation will fail if the directory at <code>path</code> is not empty.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">/**</span>
<span class="pl-c"> * Given the following dir structure, remove docs/</span>
<span class="pl-c"> * /docs</span>
<span class="pl-c"> * a.txt</span>
<span class="pl-c"> */</span>
<span class="pl-c">// Start by deleting the files in docs/, then remove docs/</span>
fs.unlink(<span class="pl-s1"><span class="pl-pds">'</span>/docs/a.txt<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.rmdir(<span class="pl-s1"><span class="pl-pds">'</span>/docs<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
});
});</pre></div>
<h4>
<a id="fsmkdirpath-mode-callback" class="anchor" href="#fsmkdirpath-mode-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.mkdir(path, [mode], callback)<a name="mkdir"></a>
</h4>
<p>Makes a directory with name supplied in <code>path</code> argument. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/mkdir.html">mkdir(2)</a>. Callback gets no additional arguments.</p>
<p>NOTE: Filer allows for, but ignores the optional <code>mode</code> argument used in node.js.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create /home and then /home/carl directories</span>
fs.mkdir(<span class="pl-s1"><span class="pl-pds">'</span>/home<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.mkdir(<span class="pl-s1"><span class="pl-pds">'</span>/home/carl<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// directory /home/carl now exists</span>
});
});</pre></div>
<h4>
<a id="fsreaddirpath-callback" class="anchor" href="#fsreaddirpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.readdir(path, callback)<a name="readdir"></a>
</h4>
<p>Reads the contents of a directory. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/readdir.html">readdir(3)</a>.
Callback gets <code>(error, files)</code>, where <code>files</code> is an array containing the names of each directory entry (i.e., file, directory, link) in the directory, excluding <code>.</code> and <code>..</code>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">/**</span>
<span class="pl-c"> * Given the following dir structure:</span>
<span class="pl-c"> * /docs</span>
<span class="pl-c"> * a.txt</span>
<span class="pl-c"> * b.txt</span>
<span class="pl-c"> * c/</span>
<span class="pl-c"> */</span>
fs.readdir(<span class="pl-s1"><span class="pl-pds">'</span>/docs<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">files</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// files now contains ['a.txt', 'b.txt', 'c']</span>
});</pre></div>
<h4>
<a id="fsclosefd-callback" class="anchor" href="#fsclosefd-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.close(fd, callback)<a name="close"></a>
</h4>
<p>Closes a file descriptor. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/close.html">close(2)</a>.
Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// Do something with open file descriptor `fd`</span>
<span class="pl-c">// Close file descriptor when done</span>
fs.<span class="pl-s3">close</span>(fd);
});</pre></div>
<h4>
<a id="fsopenpath-flags-mode-callback" class="anchor" href="#fsopenpath-flags-mode-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.open(path, flags, [mode], callback)<a name="open"></a>
</h4>
<p>Opens a file. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/open.html">open(2)</a>.
Callback gets <code>(error, fd)</code>, where <code>fd</code> is the file descriptor. The <code>flags</code> argument can be:</p>
<ul>
<li>
<code>'r'</code>: Open file for reading. An exception occurs if the file does not exist.</li>
<li>
<code>'r+'</code>: Open file for reading and writing. An exception occurs if the file does not exist.</li>
<li>
<code>'w'</code>: Open file for writing. The file is created (if it does not exist) or truncated (if it exists).</li>
<li>
<code>'w+'</code>: Open file for reading and writing. The file is created (if it does not exist) or truncated (if it exists).</li>
<li>
<code>'a'</code>: Open file for appending. The file is created if it does not exist.</li>
<li>
<code>'a+'</code>: Open file for reading and appending. The file is created if it does not exist.</li>
</ul>
<p>NOTE: Filer allows for, but ignores the optional <code>mode</code> argument used in node.js.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// Do something with open file descriptor `fd`</span>
<span class="pl-c">// Close file descriptor when done</span>
fs.<span class="pl-s3">close</span>(fd);
});</pre></div>
<h4>
<a id="fsutimespath-atime-mtime-callback" class="anchor" href="#fsutimespath-atime-mtime-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.utimes(path, atime, mtime, callback)<a name="utimes"></a>
</h4>
<p>Changes the file timestamps for the file given at path <code>path</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.html">utimes(2)</a>. Callback gets no additional arguments. Both <code>atime</code> (access time) and <code>mtime</code> (modified time) arguments should be a JavaScript Date.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> now <span class="pl-k">=</span> <span class="pl-s3">Date</span>.now();
fs.utimes(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, now, now, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Access Time and Modified Time for /myfile.txt are now updated</span>
});</pre></div>
<h4>
<a id="fsfutimesfd-atime-mtime-callback" class="anchor" href="#fsfutimesfd-atime-mtime-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.futimes(fd, atime, mtime, callback)<a name="futimes"></a>
</h4>
<p>Changes the file timestamps for the open file represented by the file descriptor <code>fd</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/utimes.html">utimes(2)</a>. Callback gets no additional arguments. Both <code>atime</code> (access time) and <code>mtime</code> (modified time) arguments should be a JavaScript Date.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-s">var</span> now <span class="pl-k">=</span> <span class="pl-s3">Date</span>.now();
fs.futimes(fd, now, now, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Access Time and Modified Time for /myfile.txt are now updated</span>
fs.<span class="pl-s3">close</span>(fd);
});
});</pre></div>
<h4>
<a id="fsfsyncfd-callback" class="anchor" href="#fsfsyncfd-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.fsync(fd, callback)<a name="fsync"></a>
</h4>
<p>NOTE: Not yet implemented, see <a href="https://github.com/filerjs/filer/issues/87">https://github.com/filerjs/filer/issues/87</a></p>
<h4>
<a id="fswritefd-buffer-offset-length-position-callback" class="anchor" href="#fswritefd-buffer-offset-length-position-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.write(fd, buffer, offset, length, position, callback)<a name="write"></a>
</h4>
<p>Writes bytes from <code>buffer</code> to the file specified by <code>fd</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/write.html">write(2), pwrite(2)</a>. The <code>offset</code> and <code>length</code> arguments describe the part of the buffer to be written. The <code>position</code> refers to the offset from the beginning of the file where this data should be written. If <code>position</code> is <code>null</code>, the data will be written at the current position. The callback gets <code>(error, nbytes)</code>, where <code>nbytes</code> is the number of bytes written.</p>
<p>NOTE: Filer currently writes the entire buffer in a single operation. However, future versions may do it in chunks.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Create a file with the following bytes.</span>
<span class="pl-s">var</span> buffer <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>, <span class="pl-c1">4</span>, <span class="pl-c1">5</span>, <span class="pl-c1">6</span>, <span class="pl-c1">7</span>, <span class="pl-c1">8</span>]);
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-s">var</span> expected <span class="pl-k">=</span> buffer.<span class="pl-sc">length</span>, written <span class="pl-k">=</span> <span class="pl-c1">0</span>;
<span class="pl-st">function</span> <span class="pl-en">writeBytes</span>(<span class="pl-vpf">offset</span>, <span class="pl-vpf">position</span>, <span class="pl-vpf">length</span>) {
length <span class="pl-k">=</span> length <span class="pl-k">||</span> buffer.<span class="pl-sc">length</span> <span class="pl-k">-</span> written;
fs.<span class="pl-s3">write</span>(fd, buffer, offset, length, position, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">nbytes</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// nbytes is now the number of bytes written, between 0 and buffer.length.</span>
<span class="pl-c">// See if we still have more bytes to write.</span>
written <span class="pl-k">+=</span> nbytes;
<span class="pl-k">if</span>(written <span class="pl-k">&lt;</span> expected)
writeBytes(written, <span class="pl-c1">null</span>);
<span class="pl-k">else</span>
fs.<span class="pl-s3">close</span>(fd);
});
}
writeBytes(<span class="pl-c1">0</span>, <span class="pl-c1">0</span>);
});</pre></div>
<h4>
<a id="fsreadfd-buffer-offset-length-position-callback" class="anchor" href="#fsreadfd-buffer-offset-length-position-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.read(fd, buffer, offset, length, position, callback)<a name="read"></a>
</h4>
<p>Read bytes from the file specified by <code>fd</code> into <code>buffer</code>. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/009695399/functions/read.html">read(2), pread(2)</a>. The <code>offset</code> and <code>length</code> arguments describe the part of the buffer to be used. The <code>position</code> refers to the offset from the beginning of the file where this data should be read. If <code>position</code> is <code>null</code>, the data will be written at the current position. The callback gets <code>(error, nbytes)</code>, where <code>nbytes</code> is the number of bytes read.</p>
<p>NOTE: Filer currently reads into the buffer in a single operation. However, future versions may do it in chunks.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>r<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// Determine size of file</span>
fs.fstat(fd, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">stats</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// Create a buffer large enough to hold the file's contents</span>
<span class="pl-s">var</span> nbytes <span class="pl-k">=</span> expected <span class="pl-k">=</span> stats.<span class="pl-sc">size</span>;
<span class="pl-s">var</span> buffer <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>(nbytes);
<span class="pl-s">var</span> read <span class="pl-k">=</span> <span class="pl-c1">0</span>;
<span class="pl-st">function</span> <span class="pl-en">readBytes</span>(<span class="pl-vpf">offset</span>, <span class="pl-vpf">position</span>, <span class="pl-vpf">length</span>) {
length <span class="pl-k">=</span> length <span class="pl-k">||</span> buffer.<span class="pl-sc">length</span> <span class="pl-k">-</span> read;
fs.read(fd, buffer, offset, length, position, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">nbytes</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> error;
<span class="pl-c">// nbytes is now the number of bytes read, between 0 and buffer.length.</span>
<span class="pl-c">// See if we still have more bytes to read.</span>
read <span class="pl-k">+=</span> nbytes;
<span class="pl-k">if</span>(read <span class="pl-k">&lt;</span> expected)
readBytes(read, <span class="pl-c1">null</span>);
<span class="pl-k">else</span>
fs.<span class="pl-s3">close</span>(fd);
});
}
readBytes(<span class="pl-c1">0</span>, <span class="pl-c1">0</span>);
});
});</pre></div>
<h4>
<a id="fsreadfilefilename-options-callback" class="anchor" href="#fsreadfilefilename-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.readFile(filename, [options], callback)<a name="readFile"></a>
</h4>
<p>Reads the entire contents of a file. The <code>options</code> argument is optional, and can take the form <code>"utf8"</code> (i.e., an encoding) or be an object literal: <code>{ encoding: "utf8", flag: "r" }</code>. If no encoding is specified, the raw binary buffer is returned via the callback. The callback gets <code>(error, data)</code>, where data is the contents of the file.</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Read UTF8 text file</span>
fs.readFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>utf8<span class="pl-pds">'</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>, <span class="pl-vpf">data</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
<span class="pl-c">// data is now the contents of /myfile.txt (i.e., a String)</span>
});
<span class="pl-c">// Read binary file</span>
fs.readFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>, <span class="pl-vpf">data</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
<span class="pl-c">// data is now the contents of /myfile.txt (i.e., a Buffer with the bytes)</span>
});</pre></div>
<h4>
<a id="fswritefilefilename-data-options-callback" class="anchor" href="#fswritefilefilename-data-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.writeFile(filename, data, [options], callback)<a name="writeFile"></a>
</h4>
<p>Writes data to a file. <code>data</code> can be a string or <code>Buffer</code>, in which case any encoding option is ignored. The <code>options</code> argument is optional, and can take the form <code>"utf8"</code> (i.e., an encoding) or be an object literal: <code>{ encoding: "utf8", flag: "w" }</code>. If no encoding is specified, and <code>data</code> is a string, the encoding defaults to <code>'utf8'</code>. The callback gets <code>(error)</code>.</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Write UTF8 text file</span>
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>...data...<span class="pl-pds">"</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
});
<span class="pl-c">// Write binary file</span>
<span class="pl-s">var</span> buffer <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>, <span class="pl-c1">4</span>, <span class="pl-c1">5</span>, <span class="pl-c1">6</span>, <span class="pl-c1">7</span>, <span class="pl-c1">8</span>]);
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, buffer, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
});</pre></div>
<h4>
<a id="fsappendfilefilename-data-options-callback" class="anchor" href="#fsappendfilefilename-data-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.appendFile(filename, data, [options], callback)<a name="appendFile"></a>
</h4>
<p>Writes data to the end of a file. <code>data</code> can be a string or a <code>Buffer</code>, in which case any encoding option is ignored. The <code>options</code> argument is optional, and can take the form <code>"utf8"</code> (i.e., an encoding) or be an object literal: <code>{ encoding: "utf8", flag: "w" }</code>. If no encoding is specified, and <code>data</code> is a string, the encoding defaults to <code>'utf8'</code>. The callback gets <code>(error)</code>.</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Append UTF8 text file</span>
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>More...<span class="pl-pds">"</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
});
fs.appendFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile.txt<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">"</span>Data...<span class="pl-pds">"</span></span>, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
});
<span class="pl-c">// '/myfile.txt' would now read out 'More...Data...'</span>
<span class="pl-c">// Append binary file</span>
<span class="pl-s">var</span> data <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">1</span>, <span class="pl-c1">2</span>, <span class="pl-c1">3</span>, <span class="pl-c1">4</span>]);
<span class="pl-s">var</span> more <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.Buffer</span>([<span class="pl-c1">5</span>, <span class="pl-c1">6</span>, <span class="pl-c1">7</span>, <span class="pl-c1">8</span>]);
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, data, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
fs.appendFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, more, <span class="pl-st">function</span> (<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span> (err) <span class="pl-k">throw</span> err;
<span class="pl-c">// '/myfile' would now contain [1, 2, 3, 4, 5, 6, 7, 8]</span>
});
});</pre></div>
<h4>
<a id="fssetxattrpath-name-value-flag-callback" class="anchor" href="#fssetxattrpath-name-value-flag-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.setxattr(path, name, value, [flag], callback)<a name="setxattr"></a>
</h4>
<p>Sets an extended attribute of a file or directory named <code>path</code>. Asynchronous <a href="http://man7.org/linux/man-pages/man2/setxattr.2.html">setxattr(2)</a>.
The optional <code>flag</code> parameter can be set to the following:</p>
<ul>
<li>
<code>XATTR_CREATE</code>: ensures that the extended attribute with the given name will be new and not previously set. If an attribute with the given name already exists, it will return an <code>EExists</code> error to the callback.</li>
<li>
<code>XATTR_REPLACE</code>: ensures that an extended attribute with the given name already exists. If an attribute with the given name does not exist, it will return an <code>ENoAttr</code> error to the callback.</li>
</ul>
<p>Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>data<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Set a simple extended attribute on /myfile</span>
fs.setxattr(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>some-information<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /myfile now has an added attribute of extra='some-information'</span>
});
<span class="pl-c">// Set a complex object attribute on /myfile</span>
fs.setxattr(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>extra-complex<span class="pl-pds">'</span></span>, { key1<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>value1<span class="pl-pds">'</span></span>, key2<span class="pl-k">:</span> <span class="pl-c1">103</span> }, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /myfile now has an added attribute of extra={ key1: 'value1', key2: 103 }</span>
});
});</pre></div>
<h4>
<a id="fsfsetxattrfd-name-value-flag-callback" class="anchor" href="#fsfsetxattrfd-name-value-flag-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.fsetxattr(fd, name, value, [flag], callback)<a name="fsetxattr"></a>
</h4>
<p>Sets an extended attribute of the file represented by the open file descriptor <code>fd</code>. Asynchronous <a href="http://man7.org/linux/man-pages/man2/setxattr.2.html">setxattr(2)</a>. See <code>fs.setxattr</code> for more details. Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>w<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Set a simple extended attribute on fd for /myfile</span>
fs.fsetxattr(fd, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>some-information<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /myfile now has an added attribute of extra='some-information'</span>
});
<span class="pl-c">// Set a complex object attribute on fd for /myfile</span>
fs.fsetxattr(fd, <span class="pl-s1"><span class="pl-pds">'</span>extra-complex<span class="pl-pds">'</span></span>, { key1<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>value1<span class="pl-pds">'</span></span>, key2<span class="pl-k">:</span> <span class="pl-c1">103</span> }, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /myfile now has an added attribute of extra={ key1: 'value1', key2: 103 }</span>
});
fs.<span class="pl-s3">close</span>(fd);
});</pre></div>
<h4>
<a id="fsgetxattrpath-name-callback" class="anchor" href="#fsgetxattrpath-name-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.getxattr(path, name, callback)<a name="getxattr"></a>
</h4>
<p>Gets an extended attribute value for a file or directory. Asynchronous <a href="http://man7.org/linux/man-pages/man2/getxattr.2.html">getxattr(2)</a>.
Callback gets <code>(error, value)</code>, where <code>value</code> is the value for the extended attribute named <code>name</code>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Get the value of the extended attribute on /myfile named `extra`</span>
fs.getxattr(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">value</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// `value` is now the value of the extended attribute named `extra` for /myfile</span>
});</pre></div>
<h4>
<a id="fsfgetxattrfd-name-callback" class="anchor" href="#fsfgetxattrfd-name-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.fgetxattr(fd, name, callback)<a name="fgetxattr"></a>
</h4>
<p>Gets an extended attribute value for the file represented by the open file descriptor <code>fd</code>.
Asynchronous <a href="http://man7.org/linux/man-pages/man2/getxattr.2.html">getxattr(2)</a>.
See <code>fs.getxattr</code> for more details. Callback gets <code>(error, value)</code>, where <code>value</code> is the value for the extended attribute named <code>name</code>.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Get the value of the extended attribute on /myfile named `extra`</span>
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>r<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.fgetxattr(fd, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">value</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// `value` is now the value of the extended attribute named `extra` for /myfile</span>
});
fs.<span class="pl-s3">close</span>(fd);
});</pre></div>
<h4>
<a id="fsremovexattrpath-name-callback" class="anchor" href="#fsremovexattrpath-name-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.removexattr(path, name, callback)<a name="removexattr"></a>
</h4>
<p>Removes the extended attribute identified by <code>name</code> for the file given at <code>path</code>. Asynchronous <a href="http://man7.org/linux/man-pages/man2/removexattr.2.html">removexattr(2)</a>. Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Remove an extended attribute on /myfile</span>
fs.removexattr(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// The `extra` extended attribute on /myfile is now gone</span>
});</pre></div>
<h4>
<a id="fsfremovexattrfd-name-callback" class="anchor" href="#fsfremovexattrfd-name-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.fremovexattr(fd, name, callback)<a name="fremovexattr"></a>
</h4>
<p>Removes the extended attribute identified by <code>name</code> for the file represented by the open file descriptor <code>fd</code>.
Asynchronous <a href="http://man7.org/linux/man-pages/man2/removexattr.2.html">removexattr(2)</a>. See <code>fs.removexattr</code> for more details.
Callback gets no additional arguments.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Remove an extended attribute on /myfile</span>
fs.<span class="pl-s3">open</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>r<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">fd</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.fremovexattr(fd, <span class="pl-s1"><span class="pl-pds">'</span>extra<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// The `extra` extended attribute on /myfile is now gone</span>
});
fs.<span class="pl-s3">close</span>(fd);
});</pre></div>
<h4>
<a id="fswatchfilename-options-listener" class="anchor" href="#fswatchfilename-options-listener" aria-hidden="true"><span class="octicon octicon-link"></span></a>fs.watch(filename, [options], [listener])<a name="watch"></a>
</h4>
<p>Watch for changes to a file or directory at <code>filename</code>. The object returned is an <code>FSWatcher</code>,
which is an <a href="http://nodejs.org/api/events.html"><code>EventEmitter</code></a> with the following additional method:</p>
<ul>
<li>
<code>close()</code> - stops listening for changes, and removes all listeners from this instance. Use this
to stop watching a file or directory after calling <code>fs.watch()</code>.</li>
</ul>
<p>The only supported option is <code>recursive</code>, which if <code>true</code> will cause a watch to be placed
on a directory, and all sub-directories and files beneath it.</p>
<p>The <code>listener</code> callback gets two arguments <code>(event, filename)</code>. <code>event</code> is either <code>'rename'</code> or <code>'change'</code>,
(currenty only <code>'rename'</code> is supported) and <code>filename</code> is the name of the file/dir which triggered the event.</p>
<p>Unlike node.js, all watch events return a path. Also, all returned paths are absolute from the root
vs. just a relative filename.</p>
<p>Examples:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Example 1: create a watcher to see when a file is created</span>
<span class="pl-s">var</span> watcher <span class="pl-k">=</span> fs.<span class="pl-s3">watch</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">event</span>, <span class="pl-vpf">filename</span>) {
<span class="pl-c">// event could be 'change' or 'rename' and filename will be '/myfile'</span>
<span class="pl-c">// Stop watching for changes</span>
watcher.<span class="pl-s3">close</span>();
});
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>data<span class="pl-pds">'</span></span>);
<span class="pl-c">// Example 2: add the listener via watcher.on()</span>
<span class="pl-s">var</span> watcher <span class="pl-k">=</span> fs.<span class="pl-s3">watch</span>(<span class="pl-s1"><span class="pl-pds">'</span>/myfile2<span class="pl-pds">'</span></span>);
watcher.on(<span class="pl-s1"><span class="pl-pds">'</span>change<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">event</span>, <span class="pl-vpf">filename</span>) {
<span class="pl-c">// event will be 'change' and filename will be '/myfile2'</span>
<span class="pl-c">// Stop watching for changes</span>
watcher.<span class="pl-s3">close</span>();
});
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/myfile2<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>data2<span class="pl-pds">'</span></span>);
<span class="pl-c">// Example 3: recursive watch on /data dir</span>
<span class="pl-s">var</span> watcher <span class="pl-k">=</span> fs.<span class="pl-s3">watch</span>(<span class="pl-s1"><span class="pl-pds">'</span>/data<span class="pl-pds">'</span></span>, { recursive<span class="pl-k">:</span> <span class="pl-c1">true</span> }, <span class="pl-st">function</span>(<span class="pl-vpf">event</span>, <span class="pl-vpf">filename</span>) {
<span class="pl-c">// event could be 'change' or 'rename' and filename will be '/data/subdir/file'</span>
<span class="pl-c">// Stop watching for changes</span>
watcher.<span class="pl-s3">close</span>();
});
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/data/subdir/file<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>data<span class="pl-pds">'</span></span>);</pre></div>
<h3>
<a id="filesystemshell" class="anchor" href="#filesystemshell" aria-hidden="true"><span class="octicon octicon-link"></span></a>FileSystemShell<a name="FileSystemShell"></a>
</h3>
<p>Many common file system shell operations are available by using a <code>FileSystemShell</code> object.
The <code>FileSystemShell</code> is used in conjuction with a <code>FileSystem</code>,
and provides augmented features. Many separate <code>FileSystemShell</code> objects can exist per
<code>FileSystem</code>, but each <code>FileSystemShell</code> is bound to a single instance of a <code>FileSystem</code>
for its lifetime.</p>
<p>A <code>FileSystemShell</code> is created by instantiating <code>Filer.FileSystem().Shell</code>:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
<span class="pl-s">var</span> sh <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>(options);
<span class="pl-s">var</span> sh2 <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>(options);
<span class="pl-c">// sh and sh2 are two separate shells, each bound to fs</span></pre></div>
<p>In addition, the constructor function can be accessed through <code>Filer</code>:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
<span class="pl-s">var</span> sh <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>();
<span class="pl-s3">Filer.Shell</span>.<span class="pl-sc">prototype</span>.<span class="pl-en">newFunction</span> <span class="pl-k">=</span> ...;
sh.newFunction();</pre></div>
<p>The <code>FileSystemShell</code> can take an optional <code>options</code> object. The <code>options</code> object
can include <code>env</code>, which is a set of environment variables. Currently supported variables
include <code>TMP</code> (the path to the temporary directory), and <code>PATH</code> (the list of known paths) and
others may be added in the future. You can also add your own, or update existing variables.</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
<span class="pl-s">var</span> sh <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>({
env<span class="pl-k">:</span> {
TMP<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>/tempdir<span class="pl-pds">'</span></span>,
PATH<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>/one:/two<span class="pl-pds">'</span></span>
}
});
<span class="pl-s">var</span> tempPath <span class="pl-k">=</span> sh.env.get(<span class="pl-s1"><span class="pl-pds">'</span>TMP<span class="pl-pds">'</span></span>);
sh.env.set(<span class="pl-s1"><span class="pl-pds">'</span>TMP<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>/newtempdir<span class="pl-pds">'</span></span>);</pre></div>
<p>NOTE: unless otherwise stated, all <code>FileSystemShell</code> methods can take relative or absolute
paths. Relative paths are resolved relative to the shell's current working directory (<code>sh.cwd</code>).
This is different from the <code>FileSystem</code>, which requires absolute paths, and has no notion
of a current working directory.</p>
<h4>
<a id="filesystemshell-properties" class="anchor" href="#filesystemshell-properties" aria-hidden="true"><span class="octicon octicon-link"></span></a>FileSystemShell Properties</h4>
<p>A <code>FileSystemShell</code> has a number of properties, including:</p>
<ul>
<li>
<code>fs</code> - (readonly) a reference to the bound <code>FileSystem</code>
</li>
<li>
<code>env</code> - (readonly) the shell's environment. The shell's environemnt <code>env</code> object has <code>get(name)</code>
and <code>set(name, value)</code> methods.</li>
</ul>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
<span class="pl-s">var</span> sh <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>();
<span class="pl-s">var</span> p <span class="pl-k">=</span> sh.env.get(<span class="pl-s1"><span class="pl-pds">'</span>PATH<span class="pl-pds">'</span></span>);
<span class="pl-c">// Store the current location</span>
<span class="pl-s">var</span> before <span class="pl-k">=</span> sh.pwd();
<span class="pl-s">var</span> after;
sh.cd(<span class="pl-s1"><span class="pl-pds">'</span>/newdir<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Get the new location</span>
after <span class="pl-k">=</span> sh.pwd();
});</pre></div>
<h4>
<a id="filesystemshell-instance-methods" class="anchor" href="#filesystemshell-instance-methods" aria-hidden="true"><span class="octicon octicon-link"></span></a>FileSystemShell Instance Methods</h4>
<p>Once a <code>FileSystemShell</code> object is created, it has the following methods. NOTE: code
examples below assume a <code>FileSystemShell</code> instance named <code>sh</code> has been created like so:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-s">var</span> fs <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">Filer.FileSystem</span>();
<span class="pl-s">var</span> sh <span class="pl-k">=</span> <span class="pl-k">new</span> <span class="pl-en">fs.Shell</span>();</pre></div>
<ul>
<li><a href="#cd">sh.cd(path, callback)</a></li>
<li><a href="#pwd">sh.pwd()</a></li>
<li><a href="#find">sh.find(dir, [options], callback)</a></li>
<li><a href="#ls">sh.ls(dir, [options], callback)</a></li>
<li><a href="#exec">sh.exec(path, [args], callback)</a></li>
<li><a href="#touch">sh.touch(path, [options], callback)</a></li>
<li><a href="#cat">sh.cat(files, callback)</a></li>
<li><a href="#rm">sh.rm(path, [options], callback)</a></li>
<li><a href="#tempDir">sh.tempDir(callback)</a></li>
<li><a href="#mkdirp">sh.mkdirp(path, callback)</a></li>
</ul>
<h4>
<a id="shcdpath-callback" class="anchor" href="#shcdpath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.cd(path, callback)<a name="cd"></a>
</h4>
<p>Changes the current working directory to the directory at <code>path</code>. The callback returns
an error if <code>path</code> does not exist, or is not a directory. Once the callback occurs
the shell's cwd is updated to the new path (you can access it via <code>sh.pwd()</code>).</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>sh.cd(<span class="pl-s1"><span class="pl-pds">'</span>/dir1<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// sh.pwd() is now '/dir1'</span>
});</pre></div>
<h4>
<a id="shpwd" class="anchor" href="#shpwd" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.pwd()<a name="pwd"></a>
</h4>
<p>Returns the shell's current working directory. See <a href="#cd">sh.cd()</a>.</p>
<h4>
<a id="shfinddir-options-callback" class="anchor" href="#shfinddir-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.find(dir, [options], callback)<a name="find"></a>
</h4>
<p>Recursively walk a directory tree, reporting back all paths that were
found along the way. Asynchronous <a href="http://pubs.opengroup.org/onlinepubs/9699919799/utilities/find.html">find(1)</a>
If given no options, <code>find</code> walks the given dir path
and the callback gives <code>function(err, found)</code>, where <code>found</code> is an array of
all paths discovered during a depth-first walk.</p>
<p>Valid options include a <code>regex</code> for pattern matching paths, allowing paths
to be ignored (e.g., <code>regex: /\.bak$/</code> to find all <code>.bak</code> files). You can
also use <code>name</code> and <code>path</code> to provide a <a href="https://github.com/isaacs/minimatch">match pattern</a> for the basename and
dirname respectively (e.g., <code>{name: '*.js'}</code> to find all JavaScript files or
<code>{path: '*-modules'}</code> to only look in folders named <code>base-modules</code>, <code>foo-modules</code>, etc.).
Finally, you can also provide an <code>exec</code> function of the form <code>function(path, next)</code> where
<code>path</code> is the current path that was found and matches any provided <code>regex</code>
(NOTE: dir paths have an '/' appended), and <code>next</code> is a callback to call
when you are done processing the path.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-st">function</span> <span class="pl-en">processPath</span>(<span class="pl-vpf">path</span>, <span class="pl-vpf">next</span>) {
<span class="pl-c">// Process the path somehow, in this case we print it.</span>
<span class="pl-c">// Dir paths end with /</span>
<span class="pl-k">if</span>(path.endsWith(<span class="pl-s1"><span class="pl-pds">'</span>/<span class="pl-pds">'</span></span>)) {
<span class="pl-en">console</span><span class="pl-s3">.log</span>(<span class="pl-s1"><span class="pl-pds">'</span>Found dir: <span class="pl-pds">'</span></span> <span class="pl-k">+</span> path);
} <span class="pl-k">else</span> {
<span class="pl-en">console</span><span class="pl-s3">.log</span>(<span class="pl-s1"><span class="pl-pds">'</span>Found file: <span class="pl-pds">'</span></span> <span class="pl-k">+</span> path);
}
<span class="pl-c">// All done, let the process continue by invoking second arg:</span>
next();
}
<span class="pl-c">// Get every path (NOTE: no name or regex provided) below the root, depth first</span>
sh.<span class="pl-s3">find</span>(<span class="pl-s1"><span class="pl-pds">'</span>/<span class="pl-pds">'</span></span>, {exec<span class="pl-k">:</span> processPath}, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">found</span>) {
<span class="pl-c">/* find command is finished, `found` contains the flattened list as an Array */</span>
});
<span class="pl-c">// Find all files that look like map201.jpg, map202.jpg in the /data dir</span>
sh.<span class="pl-s3">find</span>(<span class="pl-s1"><span class="pl-pds">'</span>/data<span class="pl-pds">'</span></span>, {regex<span class="pl-k">:</span><span class="pl-sr"> <span class="pl-pds">/</span>map20<span class="pl-c1">\d</span><span class="pl-cce">\.</span>jpg<span class="pl-k">$</span><span class="pl-pds">/</span></span>, exec<span class="pl-k">:</span> processPath}, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-c">/* find command is finished */</span>
});
<span class="pl-c">// Find and delete all *.bak files under /app/user</span>
sh.<span class="pl-s3">find</span>(<span class="pl-s1"><span class="pl-pds">'</span>/app/user<span class="pl-pds">'</span></span>, {
name<span class="pl-k">:</span> <span class="pl-s1"><span class="pl-pds">'</span>*.bak<span class="pl-pds">'</span></span>,
<span class="pl-en">exec</span>: <span class="pl-st">function</span>(<span class="pl-vpf">path</span>, <span class="pl-vpf">next</span>) {
sh.rm(path, next);
}
}, <span class="pl-st">function</span> <span class="pl-en">callback</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">found</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-k">if</span>(found.<span class="pl-sc">length</span>) {
<span class="pl-en">console</span><span class="pl-s3">.log</span>(<span class="pl-s1"><span class="pl-pds">'</span>Deleted the following <span class="pl-pds">'</span></span> <span class="pl-k">+</span> found.<span class="pl-sc">length</span> <span class="pl-k">+</span> <span class="pl-s1"><span class="pl-pds">'</span> files: <span class="pl-pds">'</span></span>, found);
}
});</pre></div>
<h4>
<a id="shlsdir-options-callback" class="anchor" href="#shlsdir-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.ls(dir, [options], callback)<a name="ls"></a>
</h4>
<p>Get the listing of a directory, returning an array of directory entries
in the following form:</p>
<pre><code>{
path: &lt;String&gt; the basename of the directory entry
links: &lt;Number&gt; the number of links to the entry
size: &lt;Number&gt; the size in bytes of the entry
modified: &lt;Number&gt; the last modified date/time
type: &lt;String&gt; the type of the entry
contents: &lt;Array&gt; an optional array of child entries, if this entry is itself a directory
}
</code></pre>
<p>By default <code>sh.ls()</code> gives a shallow listing. If you want to follow
directories as they are encountered, use the <code>recursive=true</code> option. NOTE:
you should not count on the order of the returned entries always being the same.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">/**</span>
<span class="pl-c"> * Given a dir structure of:</span>
<span class="pl-c"> *</span>
<span class="pl-c"> * /dir</span>
<span class="pl-c"> * file1</span>
<span class="pl-c"> * file2</span>
<span class="pl-c"> * dir2/</span>
<span class="pl-c"> * file3</span>
<span class="pl-c"> */</span>
<span class="pl-c">// Shallow listing</span>
sh.ls(<span class="pl-s1"><span class="pl-pds">'</span>/dir<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">entries</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// entries is now an array of 3 file/dir entries under /dir</span>
});
<span class="pl-c">// Deep listing</span>
sh.ls(<span class="pl-s1"><span class="pl-pds">'</span>/dir<span class="pl-pds">'</span></span>, { recursive<span class="pl-k">:</span> <span class="pl-c1">true</span> }, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">entries</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// entries is now an array of 3 file/dir entries under /dir.</span>
<span class="pl-c">// The entry object for '/dir2' also includes a `contents` property,</span>
<span class="pl-c">// which is an array of 1 entry element for `file3`.</span>
});</pre></div>
<h4>
<a id="shexecpath-args-callback" class="anchor" href="#shexecpath-args-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.exec(path, [args], callback)<a name="exec"></a>
</h4>
<p>Attempts to execute the .js command located at <code>path</code>. The <code>sh.exec</code> method
enables apps to install larger programs into the file system and run them
later without having to re-download. Such commands should be written so as
to assume the existence of 3 global variables, which will be defined at runtime:</p>
<ul>
<li>
<code>fs</code> - [FileSystem] the <code>FileSystem</code> object bound to this shell.</li>
<li>
<code>args</code> - [Array] a list of any arguments for the command, or the empty list</li>
<li>
<code>callback</code> - [Function] a callback function of the form <code>function callback(error, result)</code>
to call when done.</li>
</ul>
<p>The .js command's contents should be the body of a function that
looks like this:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-st">function</span>(<span class="pl-vpf">fs</span>, <span class="pl-vpf">args</span>, <span class="pl-vpf">callback</span>) {
<span class="pl-c">//-------------------------commmand code here---------</span>
<span class="pl-c">// ...</span>
<span class="pl-c">//----------------------------------------------------</span>
}</pre></div>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Simple command to delete a file.</span>
<span class="pl-s">var</span> cmd <span class="pl-k">=</span> <span class="pl-s1"><span class="pl-pds">"</span>fs.unlink(args[0], callback);<span class="pl-pds">"</span></span>
<span class="pl-c">// Write the file to the filesystem</span>
fs.writeFile(<span class="pl-s1"><span class="pl-pds">'</span>/cmd.js<span class="pl-pds">'</span></span>, cmd, callback(err) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// Execute the command</span>
sh.<span class="pl-s3">exec</span>(<span class="pl-s1"><span class="pl-pds">'</span>/cmd.js<span class="pl-pds">'</span></span>, [ <span class="pl-s1"><span class="pl-pds">'</span>/file<span class="pl-pds">'</span></span> ], <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">result</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
});
});</pre></div>
<h4>
<a id="shtouchpath-options-callback" class="anchor" href="#shtouchpath-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.touch(path, [options], callback)<a name="touch"></a>
</h4>
<p>Create a file if it does not exist, or update the access and modified
times if it does. Valid options include:</p>
<ul>
<li>
<code>updateOnly</code> - <code>true</code> if the file's access/modified dates are to be updated
only (but missing file not to be)</li>
<li>
<code>date</code> - a date to use instead of the current date and time when updating
access and modified dates.</li>
</ul>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>sh.touch(<span class="pl-s1"><span class="pl-pds">'</span>/newfile<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
fs.exists(<span class="pl-s1"><span class="pl-pds">'</span>/newfile<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">exists</span>) {
<span class="pl-c">// exists is now true.</span>
}
});</pre></div>
<h4>
<a id="shcatfiles-callback" class="anchor" href="#shcatfiles-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.cat(files, callback)<a name="cat"></a>
</h4>
<p>Concatenates multiple files into a single string, with each file
separated by a newline character. The <code>files</code> argument should be
a String (i.e., path to a single file) or an Array of Strings (i.e.,
multiple paths for multiple files).</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>sh.cat([ <span class="pl-s1"><span class="pl-pds">'</span>./file1<span class="pl-pds">'</span></span>, <span class="pl-s1"><span class="pl-pds">'</span>../file2<span class="pl-pds">'</span></span> ], <span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">data</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// data is now the contents of file1 and file2 joined</span>
});</pre></div>
<h4>
<a id="shrmpath-options-callback" class="anchor" href="#shrmpath-options-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.rm(path, [options], callback)<a name="rm"></a>
</h4>
<p>Removes (deletes) the file or directory at <code>path</code>. If <code>path</code> is a file, it will
be removed. If <code>path</code> is a directory, it will be removed if it is empty, otherwise
the callback will receive an error. In order to remove non-empty directories,
use the <code>recursive=true</code> option.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre>sh.rm(<span class="pl-s1"><span class="pl-pds">'</span>./file<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// ./file is now removed</span>
});
sh.rm(<span class="pl-s1"><span class="pl-pds">'</span>/dir<span class="pl-pds">'</span></span>, { recursive<span class="pl-k">:</span> <span class="pl-c1">true</span> }, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// /dir and all its children are now removed</span>
});</pre></div>
<h4>
<a id="shtempdircallback" class="anchor" href="#shtempdircallback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.tempDir(callback)<a name="tempDir"></a>
</h4>
<p>Gets the path to the shell's temporary directory, creating it if it
does not already exist. The temp directory to use is specified in the
<code>env.TMP</code> environment variable. The callback receives an error
and the <code>tempDir</code> path. NOTE: it is safe to call this many times (i.e.,
the temp dir will only be created once). No effort is made to clean-up
the temp dir, and it is up to the caller to destroy it if desired.</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Default /tmp dir</span>
sh.tempDir(<span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">tmp</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// tmp is now '/tmp' by default, and /tmp exists</span>
});
<span class="pl-c">// Specify a tmp dir path</span>
sh.env.TMP <span class="pl-k">=</span> <span class="pl-s1"><span class="pl-pds">'</span>/temporary<span class="pl-pds">'</span></span>
sh.tempDir(<span class="pl-st">function</span>(<span class="pl-vpf">err</span>, <span class="pl-vpf">tmp</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// tmp is now '/temporary', and /temporary exists</span>
});</pre></div>
<h4>
<a id="shmkdirppath-callback" class="anchor" href="#shmkdirppath-callback" aria-hidden="true"><span class="octicon octicon-link"></span></a>sh.mkdirp(path, callback)<a name="mkdirp"></a>
</h4>
<p>Recursively creates the directory at the provided path. If the
directory already exists, no error is returned. All parents must
be valid directories (not files).</p>
<p>Example:</p>
<div class="highlight highlight-javascript"><pre><span class="pl-c">// Default empty filesystem</span>
sh.mkdirp(<span class="pl-s1"><span class="pl-pds">'</span>/test/mkdirp<span class="pl-pds">'</span></span>, <span class="pl-st">function</span>(<span class="pl-vpf">err</span>) {
<span class="pl-k">if</span>(err) <span class="pl-k">throw</span> err;
<span class="pl-c">// the root '/' now contains a directory 'test' containing the directory 'mkdirp'</span>
});</pre></div>
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