\Header{save}{Save R Objects}
\methalias{save.image}{save}
\alias{sys.load.image}{save}
\alias{sys.save.image}{save}
\keyword{file}{save}
\begin{Description}\relax
\code{save} writes an external representation of \R{} objects to the
specified file.  The objects can be read back from the file at a later
date by using the function \code{load} (or \code{data} in some cases).

\code{save.image()} is just a short-cut for \dQuote{save my current
environment},
i.e., \code{save(list = ls(all=TRUE), file = ".RData")}.  It is what
also happens with \code{\Link{q}("yes")}.
\end{Description}
\begin{Usage}
\begin{verbatim}
save(..., list = character(0), file = stop("'file' must be specified"),
     ascii = FALSE, version = NULL, envir = parent.frame(), 
     compress = FALSE)
save.image(file = ".RData", version = NULL, ascii = FALSE,
           compress = FALSE, safe = TRUE)

sys.load.image(name, quiet)
sys.save.image(name)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{...}] the names of the objects to be saved.
\item[\code{list}] A character vector containing the names of objects to be
saved.
\item[\code{file}] a connection or the name of the file where the data will be
saved.  Must be a file name for workspace format version 1.
\item[\code{ascii}] if \code{TRUE}, an ASCII representation of the data is
written.  This is useful for transporting data between machines of
different types.  The default value of \code{ascii} is \code{FALSE}
which leads to a more compact binary file being written.
\item[\code{version}] the workspace format version to use.  \code{NULL}
specifies the current default format.  The version used from \R{}
0.99.0 to \R{} 1.3.1 was version 1.  The default format as from \R{}
1.4.0 is version 2.
\item[\code{envir}] environment to search for objects to be saved.
\item[\code{compress}] logical specifying whether saving to a named file is to
use compression. Ignored when \code{file} is a connection and for
workspace format version 1.
\item[\code{safe}] logical.  If \code{TRUE}, a temporary file is used for
creating the saved workspace.  The temporary file is renamed to
\code{file} if the save succeeds.  This preserves an existing
workspace \code{file} if the save fails, but at the cost of using
extra disk space during the save.
\item[\code{name}] name of image file to save or load.
\item[\code{quiet}] logical specifying whether a message should be printed.
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
All \R{} platforms use the XDR representation of binary objects in
binary save-d files, and these are portable across all \R{} platforms.

Default values for the \code{ascii}, \code{compress}, \code{safe} and
\code{version} arguments can be modified with
the \code{save.defaults} option (used both by \code{save} and
\code{save.image}). If a \code{save.image.defaults}
option is set it overrides \code{save.defaults} for function
\code{save.image} (which allows to have different defaults). This
mechanism is experimental and subject to change.

\code{sys.save.image} is a system function that is called by \code{q()}
and its GUI analogs; \code{sys.load.image} is called by the startup code.
These functions should not be called directly and are subject to change.

\code{sys.save.image} closes all connections first, to ensure that it
is able to open a connection to save the image.  This is appropriate
when called from \code{q()} and allies, but reinforces the warning
that it should not be called directly.
\end{Details}
\begin{Section}{Warning}
The \code{...} arguments only give the \emph{names} of the objects
to be saved: they are searched for in the environment given by the
\code{envir} argument, and the actual objects given as arguments need
not be those found.  

Saved \R{} objects are binary files, even those saved with
\code{ascii=TRUE}, so ensure that they are transferred without
conversion of end of line markers.  The lines are delimited by LF on
all platforms.
\end{Section}
\begin{SeeAlso}\relax
\code{\Link{dput}}, \code{\Link{dump}}, \code{\Link{load}},
\code{\Link{data}}.
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
x <- runif(20)
y <- list(a = 1, b = TRUE, c = "oops")
save(x, y, file = "xy.Rdata")
save.image()
unlink("xy.Rdata")
unlink(".RData")

# set save defaults using option:
options(save.defaults=list(ascii=TRUE, safe=FALSE))
save.image()
unlink(".RData")
\end{ExampleCode}
\end{Examples}

