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, 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, ``$R_HOME/etc/Renviron.site`' is used. 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`'. 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 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 to a Unix shell. In particular quotes are stripped, and backslashes are removed except inside quotes.

### Note

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.

### See Also

`.Last` for final actions before termination.

### Examples

    ## Some examples with a Unix flavour
    # ~/.Renviron
    R_LIBS=~/R/library
    PAGER=/usr/local/bin/less

    # .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")

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

    ## then we get
    > cat(Sys.getenv("FOOBAR"), "\n")
    coo\bardoh\exabc"def'

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