Sys.getenv: Get Environment Variables
In robertzk/monadicbase: The R Base Package

Description Usage Arguments Details Value See Also Examples

Sys.getenv obtains the values of the environment variables.

1	Sys.getenv(x = NULL, unset = "", names = NA)

`x`	a character vector, or `NULL`.
`unset`	a character string.
`names`	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 =.)

When x is missing and names is not false, the result is of class "Dlist" in order to get a nice print method.

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.

## 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)
head(s, 12)# using the Dlist print() method

## Language and Locale settings -- but rather use Sys.getlocale()
s[grep("^L(C|ANG)", names(s))]