Chapter 5 Running R

How to start R and what command-line options are available is discussed in Invoking R in An Introduction to R.

You should ensure that the shell has set adequate resource limits: R expects a stack size of at least 8MB and to be able to open at least 256 file descriptors. (Any modern OS should have default limits at least as large as these, but apparently NetBSD may not. Use the shell command ulimit (sh/bash) or limit (csh/tcsh) to check.)

R makes use of a number of environment variables, the default values of many of which are set in file R_HOME/etc/Renviron (there are none set by default on Windows and hence no such file). These are set at configure time, and you would not normally want to change them – a possible exception is R_PAPERSIZE (see Setting paper size). The paper size will be deduced from the ‘LC_PAPER’ locale category if it exists and R_PAPERSIZE is unset, and this will normally produce the right choice from ‘a4’ and ‘letter’ on modern Unix-alikes (but can always be overridden by setting R_PAPERSIZE).

Various environment variables can be set to determine where R creates its per-session temporary directory. The environment variables TMPDIR, TMP and TEMP are searched in turn and the first one which is set and points to a writable area is used. If none do, the final default is /tmp on Unix-alikes and the value of R_USER on Windows. The path should be an absolute path not containing spaces (and it is best to avoid non-alphanumeric characters such as +).

Some Unix-alike systems are set up to remove files and directories periodically from /tmp, for example by a cron job running tmpwatch. Set TMPDIR to another directory before starting long-running jobs on such a system.

Note that TMPDIR will be used to execute configure scripts when installing packages, so if /tmp has been mounted as ‘noexec’, TMPDIR needs to be set to a directory from which execution is allowed.