Startup {base}R Documentation

Initialization at Start of an R Session

Description

In R, the startup mechanism is as follows. If a file `.Renviron', or a file pointed to by R\_ENVIRON or `~/.Renviron', exists, it is processed to set environmental variables. (This is suppressed by the flag --no-environ.) See Details for how the file is read.

Then R searches for the site-wide startup profile unless the command line option --no-site-file was given. The name of this file is taken from the value of the R\_PROFILE environment variable. If this variable is unset, the default is `$R_HOME/etc/Rprofile'. This code is loaded into package base.

Then, unless --no-init-file was given, R searches for a file called `.Rprofile' in the current directory or in the user's home directory (in that order) and sources it into the user workspace.

It then loads a saved image of the user workspace from `.RData' if there is one (unless --no-restore-data was specified, or --no-restore).

Finally, if a function .First exists, it is executed as .First().

The functions .First and .Last can be defined in the appropriate startup profiles or reside in `.RData'.

The commands history is read from the file specified by the environment variable R_HISTFILE (default .Rhistory) unless --no-restore-history was specified (or --no-restore).

The command-line flag --vanilla implies --no-init-file, --no-restore and --no-environ.

Usage

.First <- function() { ...... }

.Rprofile <startup file>

Details

Lines in a `.Renviron' file should be either comment lines starting with #, or lines of the form name=value. The latter sets the environmental variable name to value, overriding an existing value. If value is of the form ${foo-bar}, the value is that of the environmental variable foo if that exists and is set to a non-empty value, otherwise bar. This construction can be nested, so bar can be of the same form (as in ${foo-${bar-blah}}).

Leading and trailing white space in value are stripped. No other interpretation of value is performed. In particular, if it is enclosed in quotes, the quotes form part of the value.

Note

Prior to R version 1.2.1, `.Rprofile' was sourced after `.RData' was loaded, although the documented order was as here.

The format for `.Renviron' files was changed in version 1.2.0. Older files are quite likely to work but may generate warnings on startup if they contained unnecessary export statements.

See Also

.Last for final actions before termination.