EnvVar {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.

`HOME`:
  The user's ‘home’ directory.
`LANGUAGE`:
  Optional. The language(s) to be used for message translations.
`LC_ALL`:
  (etc) Optional. Use to set various aspects of the locale – see `Sys.getlocale`.
`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_ENVIRON`:
  Optional. The path to the site environment file: see Startup.
`R_GSCMD`:
  Optional. The path to GhostScript.
`R_HISTFILE`:
  Optional. The path of the history file: see Startup.
`R_HISTSIZE`:
  Optional. The maximum size of the history file, in lines.
`R_HOME`:
  The top-level directory of the R installation. Set by R.
`R_LIBS`:
  Optional. Setting for `.libPaths`.
`R_LIBS_SITE`:
  Optional. Setting for `.libPaths`.
`R_LIBS_USER`:
  Optional. Setting for `.libPaths`.
`R_PAPERSIZE`:
  Optional. The default papersize, e.g. for `pdf` and `postscript`.
`R_PROFILE`:
  Optional. The path to the site profile file: see Startup.
`R_RD4DVI`:
  Options for `latex` processing of `Rd` files.
`R_RD4PDF`:
  Options for `pdflatex` processing of `Rd` files.
`TMPDIR`, `TMP`, `TEMP`:
  Consulted (in that order) when setting the temporary directory. See `tempdir`.
`TZ`:
  Optional. The current timezone. See `as.POSIXlt` for the system-specific formats.
`no_proxy`, `http_proxy`, `ftp_proxy`:
  (and more). Optional. Settings for `download.file`.

### 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 default editor.
`PAGER`:
  The path to default pager.
`R_BROWSER`:
  The path to default browser.
`R_DOC_DIR`:
  The location of the R ‘doc’ directory.
`R_DVIPSCMD`:
  The path to `dvips`.
`R_INCLUDE_DIR`:
  The location of the R ‘include’ directory.
`R_LATEXCMD`:
  The path to `latex`.
`R_MAKEINDEXCMD`:
  The path to `makeindex`.
`R_PDFVIEWER`:
  The path to default PDF viewer.
`R_PLATFORM`:
  The platform – a string of the form `cpu-vendor-os`, see `R.Version`.
`R_PRINTCMD`:
  Print command to be used by `postscript`.
`R_SHARE_DIR`:
  The location of the R ‘share’ directory.
`R_UNZIPCMD`:
  The path to `unzip`.
`R_ZIPCMD`:
  The path to `zip`.

### See Also

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

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