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<table width="100%" summary="page for libPaths {base}"><tr><td>libPaths {base}</td><td style="text-align: right;">R Documentation</td></tr></table>

<h2>Search Paths for Packages</h2>

<h3>Description</h3>

<code>.libPaths</code> gets/sets the library trees within which packages are
looked for.

<h3>Usage</h3>

<pre>
.libPaths(new)

.Library
.Library.site
</pre>

<h3>Arguments</h3>

<table summary="R argblock">
<tr valign="top"><td><code>new</code></td>
<td>
a character vector with the locations of R library
trees. Tilde expansion (<code><a href="path.expand.html">path.expand</a></code>) is done, and if
any element contains one of <code>*?[</code>, globbing is done where
supported by the platform: see <code><a href="Sys.glob.html">Sys.glob</a></code>.
</td></tr>
</table>

<h3>Details</h3>

<code>.Library</code> is a character string giving the location of the
default library, the &lsquo;library&rsquo; subdirectory of R_HOME.

<code>.Library.site</code> is a (possibly empty) character vector giving the
locations of the site libraries, by default the &lsquo;site-library&rsquo;
subdirectory of R_HOME (which may not exist).

<code>.libPaths</code> is used for getting or setting the library trees that
R knows about (and hence uses when looking for packages). If called
with argument <code>new</code>, the library search path is set to
the existing directories in <code>unique(c(new, .Library.site, .Library))</code>
and this is returned. If given no argument, a character vector with
the currently active library trees is returned.

How paths <code>new</code> with a trailing slash are treated is
OS-dependent. On a POSIX filesystem existing directories can usually
be specified with a trailing slash: on Windows filepaths with a
trailing slash (or backslash) are invalid and so will never be added
to the library search path.

The library search path is initialized at startup from the environment
variable R_LIBS (which should be a colon-separated list of
directories at which R library trees are rooted) followed by those in
environment variable R_LIBS_USER. Only directories which exist
at the time will be included.

By default R_LIBS is unset, and R_LIBS_USER is set to
directory &lsquo;R/<var>R.version$platform</var>-library/<var>x.y</var>&rsquo;
of the home directory (or &lsquo;Library/R/<var>x.y</var>/library&rsquo; for
CRAN macOS builds), for R <var>x.y.z</var>.

<code>.Library.site</code> can be set via the environment variable
R_LIBS_SITE (as a non-empty colon-separated list of library trees).

Both R_LIBS_USER and R_LIBS_SITE feature possible
expansion of specifiers for R version specific information as part of
the startup process. The possible conversion specifiers all start
with a % and are followed by a single letter (use %%
to obtain %), with currently available conversion
specifications as follows:

<dl>
<dt>%V</dt><dd>R version number including the patchlevel (e.g.,
2.5.0).
</dd>
<dt>%v</dt><dd>R version number excluding the patchlevel (e.g.,
2.5).
</dd>
<dt>%p</dt><dd>the platform for which R was built, the value of
<code><a href="Version.html">R.version</a>$platform</code>.
</dd>
<dt>%o</dt><dd>the underlying operating system, the value of
<code><a href="Version.html">R.version</a>$os</code>.
</dd>
<dt>%a</dt><dd>the architecture (CPU) R was built on/for, the
value of <code><a href="Version.html">R.version</a>$arch</code>.
</dd>
</dl>

(See <code><a href="Version.html">version</a></code> for details on R version information.)

Function <code>.libPaths</code> always uses the values of <code>.Library</code>
and <code>.Library.site</code> in the base namespace. <code>.Library.site</code>
can be set by the site in &lsquo;Rprofile.site&rsquo;, which should be
followed by a call to <code>.libPaths(.libPaths())</code> to make use of the
updated value.

For consistency, the paths are always normalized by
<code><a href="normalizePath.html">normalizePath</a>(winslash = "/")</code>.

<h3>Value</h3>

A character vector of file paths.

<h3>References</h3>

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth &amp; Brooks/Cole.

<code><a href="library.html">library</a></code>

<h3>Examples</h3>

<pre>
.libPaths() # all library trees R knows about
</pre>

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