EnvVar
Environment Variables
Details of some of the environment variables which affect an R session.
- Keywords
- utilities
Details
It is impossible to list all the environment variables which can affect an R session: some affect the OS system functions which R uses, 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
. Consulted at startup.MAKEINDEX
:The path to
makeindex
. If unset to a value determined when R was built. Used by the emulation mode oftexi2dvi
andtexi2pdf
.R_BATCH
:Optional -- set in a batch session, that is one started by
R CMD BATCH
. Most often set to""
, so test by something like!is.na(Sys.getenv("R_BATCH", NA))
.R_BROWSER
:The path to the default browser. Used to set the default value of
options("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
.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
,bitmap
andembedFonts
. Consulted when those functions are invoked. Since it will be treated as if passed tosystem
, 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. For the
readline
command-line interface it takes effect when the history is saved (bysavehistory
or at the end of a session). ForRgui
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: seeRconsole
.R_HOME
:The top-level directory of the R installation: see
R.home
. 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
.R_LIBS_SITE
:Optional. Used for initial setting of
.libPaths
.R_LIBS_USER
:Optional. Used for initial setting of
.libPaths
.R_PAPERSIZE
:Optional. Used to set the default for
options("papersize")
, e.g.used bypdf
andpostscript
.R_PCRE_JIT_STACK_MAXSIZE
:Optional. Consulted when PCRE's JIT pattern compiler is first used. See
grep
.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
, seeR.Version
.R_PROFILE
:Optional. The path to the site profile file: see Startup. Consulted at startup.
R_RD4PDF
:Options for
pdflatex
processing ofRd
files. Used byR 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 ofTEXI2DVI
, and if that is unset to a value determined when R was built. Consulted at startup to set the default foroptions("texi2dvi")
, used bytexi2dvi
andtexi2pdf
in package tools.R_UNZIPCMD
:The path to
unzip
. Sets the initial value foroptions("unzip")
on a Unix-alike when namespace utils is loaded.R_ZIPCMD
:The path to
zip
. Used byzip
and byR CMD INSTALL --build
on Windows.TMPDIR
,TMP
,TEMP
:Consulted (in that order) when setting the temporary directory for the session: see
tempdir
.TMPDIR
is also used by some of the utilities see the help forbuild
.TZ
:Optional. The current time zone. See
Sys.timezone
for the system-specific formats. Consulted as needed.no_proxy
,http_proxy
,ftp_proxy
:(and more). Optional. Settings for
download.file
: see its help for further details.
Unix-specific
Some variables set on Unix-alikes, and not (in general) on Windows.
DISPLAY
:Optional: used by
X11
, Tk (in package tcltk), the data editor and various packages.EDITOR
:The path to the default editor: sets the default for
options("editor")
when namespace utils is loaded.PAGER
:The path to the pager with the default setting of
options("pager")
. The default value is chosen at configuration, usually as the path toless
.R_PRINTCMD
:Sets the default for
options("printcmd")
, which sets the default print command to be used bypostscript
.R_SUPPORT_OLD_TARS
logical. Sets the default for the
support_old_tars
argument ofuntar
. Should be set toTRUE
if an old systemtar
command is used which does not support eitherxz
compression or automagically detecting compression type.
Windows-specific
Some Windows-specific variables are
GSC
:Optional: the path to Ghostscript, used if
R_GSCMD
is not set.R_USER
:The user's ‘home’ directory. Set by R. (
HOME
will be set to the same value if not already set.)TZDIR
:Optional. The top-level directory of the time-zone database. See
Sys.timezone
.
See Also
Sys.getenv
and Sys.setenv
to read and set
environmental variables in an R session.
gctorture
for environment variables controlling garbage
collection.