Sys.getenv {base}

R Documentation

Get Environment Variables

Description

Sys.getenv obtains the values of the environment variables.

Usage

Sys.getenv(x = NULL, unset = "")

Arguments

x	a character vector, or NULL.
unset	a character string.

Details

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.

Value

A vector of the same length as x, with 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.

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.

Examples

## 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))]

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