Startup {base} | R Documentation

## Initialization at Start of an R Session

### Description

In R, the startup mechanism is as follows.

Unless `--no-environ` was given on the command line, R searches for user and site files to process for setting environment variables. The name of the site file is the one pointed to by the environment variable `R_ENVIRON`; if this is unset or empty, ‘`$R_HOME/etc/Renviron.site`’ is used (if it exists, which it does not in a “factory-fresh” installation). The user files searched for are ‘`.Renviron`’ in the current or in the user's home directory (in that order). See Details for how the files are 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.site`’, which is used if it exists (which it does not in a “factory-fresh” installation). This code is loaded into package base. Users need to be careful not to unintentionally overwrite objects in base, and it is normally advisable to use `local` if code needs to be executed: see the examples.

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`, on the command line).

Next, if a function `.First` is found on the search path, it is executed as `.First()`. Finally, function `.First.sys()` in the base package is run. This calls `require` to attach the default packages specified by `options("defaultPackages")`.

A function `.First` (and `.Last`) can be defined in appropriate ‘`.Rprofile`’ or ‘`Rprofile.site`’ files or have been saved in ‘`.RData`’. If you want a different set of packages than the default ones when you start, insert a call to `options` in the ‘`.Rprofile`’ or ‘`Rprofile.site`’ file. For example, `options(defaultPackages = character())` will attach no extra packages on startup. Alternatively, set `R_DEFAULT_PACKAGES=NULL` as an environment variable before running R. Using `options(defaultPackages = "")` or `R_DEFAULT_PACKAGES=""` enforces the R system default.

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-site-file`, `--no-init-file`, `--no-restore` and `--no-environ`.

### Usage

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

    .Rprofile <startup file>

### Details

Note that there are two sorts of files used in startup: environment files which contain lists of environment variables to be set, and profile files which contain R code.

Lines in a site or user environment 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. `value` is processed in a similar way to a Unix shell. In particular quotes are stripped, and backslashes are removed except inside quotes.

### Historical notes

Prior to R version 1.4.0, the environment files searched were ‘`.Renviron`’ in the current directory, the file pointed to by `R_ENVIRON` if set, and ‘`.Renviron`’ in the user's home directory.

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

The format for site and user environment 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.

Values in environment files were not processed prior to version 1.4.0.

### Note

The file ‘`$R_HOME/etc/Renviron`’ is always read very early in the start-up processing. It contains environment variables set by R in the configure process. Values in that file can be overriden in site or user environment files: do not change ‘`$R_HOME/etc/Renviron`’ itself.

### See Also

`.Last` for final actions before termination.

For profiling code, see `Rprof`.

### Examples

    ## Not run:
    # Example ~/.Renviron on Unix
    R_LIBS=~/R/library
    PAGER=/usr/local/bin/less

    # Example .Renviron on Windows
    R_LIBS=C:/R/library
    MY_TCLTK=yes
    TCL_LIBRARY=c:/packages/Tcl/lib/tcl8.4

    # Example of .Rprofile
    options(width=65, digits=5)
    options(show.signif.stars=FALSE)
    ps.options(horizontal=FALSE)
    set.seed(1234)
    .First <- function() cat("\n   Welcome to R!\n\n")
    .Last <- function()  cat("\n   Goodbye!\n\n")

    # Example of Rprofile.site
    local({
      old <- getOption("defaultPackages")
      options(defaultPackages = c(old, "MASS"))
    })

    ## if .Renviron contains
    FOOBAR="coo\bar"doh\ex"abc\"def'"

    ## then we get
    > cat(Sys.getenv("FOOBAR"), "\n")
    coo\bardoh\exabc"def'
    ## End(Not run)

[Package base version 2.0.1 Index]