Sys.getenv

R Base 3.6.2

Sys.getenv obtains the values of the environment variables.

Syntax

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

Arguments

Parameter	Description
`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.

Return Value

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

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. POSIX requires the OS to distinguish, and all known current R platforms do.

Examples

Example

# NOT RUN {
## 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))]
# }