EnvVar                 package:base                 R Documentation

Environment Variables

Description:

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

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.

     'R_BATCH': Optional - set in a batch session.

     'R_COMPLETION': Optional.  If set to 'FALSE', comand-line
          completion is not used.  (Not used by Mac OS GUI.)

     'R_DEFAULT_PACKAGES': A comma-separated list of packages which are
          to be loaded in every session.  See 'options'.

     'R_DOC_DIR': The location of the R 'doc' directory.  Set by R.

     'R_DVIPSCMD': The path to 'dvips'.  Defaults to the value of
          'DVIPS', and if that is unset to a value determined when R
          was built. Used by 'R CMD Rd2dvi', and at startup to set the
          default for 'options("latexcmd")', used by 'help(offline =
          TRUE'.

     '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'.

     '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 (by 'savehistory' or at the end of
          a session).

     '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_LATEXCMD': The path to 'latex'. Defaults to the value of
          'LATEX', and if that is unset to a value determined when R
          was built. Used by 'R CMD Rd2dvi', and at startup to set the
          default for 'options("latexcmd")', used by 'help(offline =
          TRUE'.

     '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_MAKEINDEXCMD': The path to 'makeindex'.  Defaults at startup to
          the value of 'MAKEINDEX', and if that is unset to a value
          determined when R was built.  Used by 'R CMD Rd2dvi'.

     'R_PAPERSIZE': Optional.  Use to set the default for
          'options("papersize")', e.g. used by 'pdf', 'postscript' and
          'help(offline = TRUE)'.

     'R_PDFLATEXCMD': The path to 'pdflatex'.  Defaults at startup to
          the value of 'PDFLATEX', and if that is unset to a value
          determined when R was built.  Used by 'R CMD Rd2dvi'.

     'R_PDFVIEWER': The path to the default PDF viewer.  Used by 'R CMD
          Rd2dvi'.

     'R_PLATFORM': The platform - a string of the form 'cpu-vendor-os',
          see 'R.Version'.

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

     'R_RD4DVI': Options for 'latex' processing of 'Rd' files.  Used by
          'R CMD Rd2dvi' and 'help(offline = TRUE)'.

     'R_RD4PDF': Options for 'pdflatex' processing of 'Rd' files.  Used
          by 'R CMD Rd2dvi'.

     'R_SHARE_DIR': The location of the R 'share' directory.  Set by R. 

     'R_UNZIPCMD': The path to 'unzip'.  Sets the default value for
          'options("unzip")'.

     'R_ZIPCMD': The path to 'zip'.

     'TMPDIR', 'TMP', 'TEMP': Consulted (in that order) when setting
          the temporary directory.  See 'tempdir'.

     'TZ': Optional. The current timezone.  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.

     'PAGER': The path to the default pager.

     'R_BROWSER': The path to the default browser.  Used to set the
          default value of 'options("browser")'.

     'R_PDFVIEWER': The path to the default PDF viewer.  Used by 'R CMD
          Rd2dvi'.

     'R_PRINTCMD': Sets the default for 'options("printcmd")', which
          sets the default print command to be used by 'postscript'.

See Also:

     'Sys.getenv' and 'Sys.setenv' to read and set environmental
     variables in an R session.

