\HeaderA{Sys.getenv}{Get Environment Variables}{Sys.getenv}
\keyword{environment}{Sys.getenv}
\keyword{utilities}{Sys.getenv}
\begin{Description}\relax
\code{Sys.getenv} obtains the values of the environment variables named by
\code{x}.
\end{Description}
\begin{Usage}
\begin{verbatim}
Sys.getenv(x)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] a character vector, or missing
\end{ldescription}
\end{Arguments}
\begin{Value}
A vector of the same length as \code{x}, with the variable names as
its \code{names} attribute.  Each element holds the value of the
environment variable named by the corresponding component of \code{x}
(or \code{""} if no environment variable with that name was found).

On most platforms \code{Sys.getenv()} will return a named vector giving
the values of all the environment variables.
\end{Value}
\begin{SeeAlso}\relax
\code{\LinkA{Sys.putenv}{Sys.putenv}},
\code{\LinkA{Sys.getlocale}{Sys.getlocale}} for the locale \dQuote{environment},
\code{\LinkA{getwd}{getwd}} for the working directory.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
## whether HOST is set will be shell-dependent e.g. Solaris' csh does not.
Sys.getenv(c("R_HOME", "R_PAPERSIZE", "R_PRINTCMD", "HOST"))

str(s <- Sys.getenv()) # all settings (rather do not print)

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

