R: Environment Variables (original) (raw)

Details of some of the environment variables which affect an R session.

It is impossible to list all the environment variables which can affect an R session: some affect the OS system functions which Ruses, and others will affect add-on packages. But here are notes on some of the more important ones. Those that set the defaults for options are consulted only at startup (as are some of the others).

HOME:

The user's ‘home’ directory.

LANGUAGE:

Optional. The language(s) to be used for message translations. This is consulted when needed.

LC_ALL:

(etc) Optional. Use to set various aspects of the locale – see [Sys.getlocale](../../base/help/Sys.getlocale.html). Consulted at startup.

MAKEINDEX:

The path to makeindex. If unset to a value determined when R was built. Used by the emulation mode of [texi2dvi](../../tools/html/texi2dvi.html) and[texi2pdf](../../tools/html/texi2dvi.html).

R_BATCH:

Optional – set in a batch session, that is one started by R CMD [BATCH](../../utils/html/BATCH.html). Most often set to"", so test by something like!is.na([Sys.getenv](../../base/help/Sys.getenv.html)("R_BATCH", NA)).

R_BROWSER:

The path to the default browser. Used to set the default value of [options](../../base/help/options.html)("browser").

R_COMPLETION:

Optional. If set to FALSE, command-line completion is not used. (Not used by the macOS GUI.)

R_DEFAULT_PACKAGES:

A comma-separated list of packages which are to be attached in every session. See [options](../../base/help/options.html).

R_DOC_DIR:

The location of the R ‘doc’ directory. Set by R.

R_ENVIRON:

Optional. The path to the site environment file: see Startup. Consulted at startup.

R_GSCMD:

Optional. The path to Ghostscript, used by[dev2bitmap](../../grDevices/html/dev2bitmap.html), [bitmap](../../grDevices/html/dev2bitmap.html) and[embedFonts](../../grDevices/html/embedFonts.html). Consulted when those functions are invoked. Since it will be treated as if passed to[system](../../base/help/system.html), spaces and shell metacharacters should be escaped.

R_HISTFILE:

Optional. The path of the history file: see Startup. Consulted at startup and when the history is saved.

R_HISTSIZE:

Optional. The maximum size of the history file, in lines. Exactly how this is used depends on the interface.

On Unix-alikes,

for the readline command-line interface it takes effect when the history is saved (by [savehistory](../../utils/html/savehistory.html) or at the end of a session).

On Windows,

for Rgui it controls the number of lines saved to the history file: the size of the history used in the session is controlled by the console customization: see [Rconsole](../../utils/html/Rconsole.html).

R_HOME:

The top-level directory of the Rinstallation: see [R.home](../../base/help/R.home.html). Set by R.

R_INCLUDE_DIR:

The location of the R ‘include’ directory. Set by R.

R_LIBS:

Optional. Used for initial setting of[.libPaths](../../base/help/.libPaths.html).

R_LIBS_SITE:

Optional. Used for initial setting of[.libPaths](../../base/help/.libPaths.html).

R_LIBS_USER:

Optional. Used for initial setting of[.libPaths](../../base/help/.libPaths.html).

R_PAPERSIZE:

Optional. Used to set the default for[options](../../base/help/options.html)("papersize"), e.g. used by[pdf](../../grDevices/html/pdf.html) and [postscript](../../grDevices/html/postscript.html).

R_PCRE_JIT_STACK_MAXSIZE:

Optional. Consulted when PCRE's JIT pattern compiler is first used. See [grep](../../base/help/grep.html).

R_PDFVIEWER:

The path to the default PDF viewer. Used by R CMD Rd2pdf.

R_PLATFORM:

The platform – a string of the form"cpu-vendor-os", see [R.Version](../../base/help/R.Version.html).

R_PROFILE:

Optional. The path to the site profile file: see Startup. Consulted at startup.

R_RD4PDF:

Options for pdflatex processing ofRd files. Used by R CMD Rd2pdf.

R_SHARE_DIR:

The location of the R ‘share’ directory. Set by R.

R_TEXI2DVICMD:

The path to texi2dvi. Defaults to the value of TEXI2DVI, and if that is unset to a value determined when R was built.

Only on Unix-alikes:
Consulted at startup to set the default for[options](../../base/help/options.html)("texi2dvi"), used by[texi2dvi](../../tools/html/texi2dvi.html) and [texi2pdf](../../tools/html/texi2dvi.html) in package tools.

R_TIDYCMD:

The path to HTML tidy. Used byR CMD check if _R_CHECK_RD_VALIDATE_RD2HTML_ is set to a true value (as it is by --as-cran.

R_UNZIPCMD:

The path to unzip. Sets the initial value for [options](../../base/help/options.html)("unzip") on a Unix-alike when namespace utils is loaded.

R_ZIPCMD:

The path to zip. Used by[zip](../../utils/html/zip.html) and by R CMD INSTALL --build on Windows.

TMPDIR, TMP, TEMP:

Consulted (in that order) when setting the temporary directory for the session: see[tempdir](../../base/help/tempdir.html). TMPDIR is also used by some of the utilities: see the help for [build](../../utils/html/PkgUtils.html).

TZ:

Optional. The current time zone. See[Sys.timezone](../../base/help/Sys.timezone.html) for the system-specific formats. Consulted as needed.

TZDIR:

Optional. The top-level directory of the time-zone database. See [Sys.timezone](../../base/help/Sys.timezone.html).

no_proxy, http_proxy, ftp_proxy:

(and more). Optional. Settings for [download.file](../../utils/html/download.file.html): see its help for further details.

Some variables set on Unix-alikes, and not (in general) on Windows.

[Sys.getenv](../../base/help/Sys.getenv.html) and [Sys.setenv](../../base/help/Sys.setenv.html) to read and set environmental variables in an R session.