.libPaths gets/sets the library trees within which packages are
looked for.
.libPaths(new).Library
.Library.site
a character vector with the locations of R library
trees. Tilde expansion (path.expand) is done, and if
any element contains one of *?[, globbing is done where
supported by the platform: see Sys.glob.
A character vector of file paths.
.Library is a character string giving the location of the
default library, the library subdirectory of R_HOME.
.Library.site is a (possibly empty) character vector giving the
locations of the site libraries, by default the site-library
subdirectory of R_HOME (which may not exist).
.libPaths is used for getting or setting the library trees that
R knows about (and hence uses when looking for packages). If called
with argument new, the library search path is set to
the existing directories in unique(c(new, .Library.site, .Library))
and this is returned. If given no argument, a character vector with
the currently active library trees is returned.
How paths new 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 R/R.version$platform-library/x.y
of the home directory (or Library/R/x.y/library for
CRAN macOS builds), for R x.y.z.
.Library.site can be set via the environment variable
R_LIBS_SITE (as a non-empty colon-separated list of library trees).
The library search path is initialized at startup from the environment
variable R_LIBS (which should be a semicolon-separated list of
directories at which R library trees are rooted) followed by those in
environment variable R_LIBS_USER. Only directories which exist
at the time will be included.
By default R_LIBS is unset, and R_LIBS_USER is set to
subdirectory R/win-library/x.y of the home directory,
for R x.y.z.
.Library.site can be set via the environment variable
R_LIBS_SITE (as a non-empty semicolon-separated list of library trees).
Both R_LIBS_USER and R_LIBS_SITE feature possible
expansion of specifiers for R version specific information as part of
the startup process. The possible conversion specifiers all start
with a % and are followed by a single letter (use %%
to obtain %), with currently available conversion
specifications as follows:
R version number including the patchlevel (e.g., 2.5.0).
R version number excluding the patchlevel (e.g., 2.5).
the platform for which R was built, the value of
R.version$platform.
the underlying operating system, the value of
R.version$os.
the architecture (CPU) R was built on/for, the
value of R.version$arch.
(See version for details on R version information.)
Function .libPaths always uses the values of .Library
and .Library.site in the base namespace. .Library.site
can be set by the site in Rprofile.site, which should be
followed by a call to .libPaths(.libPaths()) to make use of the
updated value.
For consistency, the paths are always normalized by
normalizePath(winslash = "/").
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.
.libPaths() # all library trees R knows about
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