Sys.setenv               package:base               R Documentation

Set or Unset Environment Variables

Description:

     'Sys.setenv' sets environment variables (for other processes
     called from within R or future calls to 'Sys.getenv' from this R
     process).

     'Sys.unsetenv' removes environment variables.

Usage:

     Sys.setenv(...)

     Sys.unsetenv(x)

Arguments:

     ...: named arguments with values coercible to a character string.

       x: a character vector, or an object coercible to character.

Details:

     The names 'setenv' and 'putenv' come from different Unix
     traditions: R also has 'Sys.putenv', but this is now deprecated.
     The internal code uses 'setenv' if available, otherwise 'putenv'.

     Non-standard R names must be quoted in 'Sys.setenv': see the
     examples.  Most platforms (and POSIX) do not allow names
     containing '"="'.

     There may be system-specific limits on the maximum length of the
     values of individual environment variables or of all environment
     variables.

Value:

     A logical vector, with elements being true if (un)setting the
     corresponding variable succeeded.  (For 'Sys.unsetenv' this
     includes attempting to remove a non-existent variable.)

Note:

     Not all systems need support 'Sys.setenv' (although all known
     current platforms do) nor 'Sys.unsetenv'. If 'Sys.unsetenv' is not
     supported, it will at least try to set the value of the
     environment variable to '""', with a  warning.

See Also:

     'Sys.getenv', Startup for ways to set environment variables for
     the R session.

     'setwd' for the working directory.

     The help for 'environment variables' lists many of the environment
     variables used by R.

Examples:

     print(Sys.setenv(R_TEST="testit", "A+C"=123))  # `A+C` could also be used
     Sys.getenv("R_TEST")
     Sys.unsetenv("R_TEST")  # may warn and not succeed
     Sys.getenv("R_TEST", unset=NA)

