Startup                 package:base                 R Documentation

_I_n_i_t_i_a_l_i_z_a_t_i_o_n _a_t _S_t_a_r_t _o_f _a_n _R _S_e_s_s_i_o_n

_D_e_s_c_r_i_p_t_i_o_n:

     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'.

_U_s_a_g_e:

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

     .Rprofile <startup file>

_D_e_t_a_i_l_s:

     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.

_N_o_t_e:

     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.

_S_e_e _A_l_s_o:

     `.Last' for final actions before termination.

_E_x_a_m_p_l_e_s:

     ## 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'

