Get Environment Variables

Sys.getenv obtains the values of the environment variables.

utilities, environment
Sys.getenv(x = NULL, unset = "", names = NA)
a character vector, or NULL.
a character string.
logical: should the result be named? If NA (the default) single-element results are not named whereas multi-element results are.

Both arguments will be coerced to character if necessary.

Setting unset = NA will enable unset variables and those set to the value "" to be distinguished, if the OS does. POSIX requires the OS to distinguish, and all known current R platforms do.


A vector of the same length as x, with (if names == TRUE) the variable names as its names attribute. Each element holds the value of the environment variable named by the corresponding component of x (or the value of unset if no environment variable with that name was found).On most platforms Sys.getenv() will return a named vector giving the values of all the environment variables, sorted in the current locale. It may be confused by names containing = which some platforms allow but POSIX does not. (Windows is such a platform: there names including = are truncated just before the first =.)

See Also

Sys.setenv, Sys.getlocale for the locale in use, getwd for the working directory.

The help for ‘environment variables’ lists many of the environment variables used by R.

  • Sys.getenv
library(base) ## whether HOST is set will be shell-dependent e.g. Solaris' csh does not. Sys.getenv(c("R_HOME", "R_PAPERSIZE", "R_PRINTCMD", "HOST")) names(s <- Sys.getenv()) # all settings (the values could be very long) ## Language and Locale settings -- but rather use Sys.getlocale() s[grep("^L(C|ANG)", names(s))]
Documentation reproduced from package base, version 3.1.3, License: Part of R 3.1.3

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