Sys.getenv
From base v3.3
by R-core R-core@R-project.org
Get Environment Variables
Sys.getenv
obtains the values of the environment variables.
- Keywords
- utilities, environment
Usage
Sys.getenv(x = NULL, unset = "", names = NA)
Arguments
- 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.
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.
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 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.
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
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)
head(s, 12)# using the Dlist print() method
## Language and Locale settings -- but rather use Sys.getlocale()
s[grep("^L(C|ANG)", names(s))]
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