The R Project SVN R

\name{update.packages}
\alias{update.packages}
\alias{installed.packages}
\alias{CRAN.packages}
\alias{download.file}
\alias{download.packages}
\alias{install.packages}
\alias{parse.description}
\title{Download packages from CRAN}}
\usage{
update.packages(lib.loc=.lib.loc, CRAN=options("CRAN"),
                method="auto", instlib=NULL)

installed.packages(lib.loc = .lib.loc)
CRAN.packages(CRAN=options("CRAN"), method="auto")

download.file(url, destfile, method="auto")
download.packages(pkgs, destdir, available=NULL,
                  CRAN=options("CRAN"), method="auto")
install.packages(pkgs, lib, available=NULL,
                  CRAN=options("CRAN"), method="auto")

parse.description <- function(desc)
}
\arguments{ 
 \item{lib.loc}{A character vector describing the location of R
     library trees to search through (and update packages therein).}
 \item{CRAN}{Base URL of the CRAN mirror to use, i.e., URL of a CRAN
     root such as \code{"http://www.ci.tuwien.ac.at/R"} or
     \code{"http://lib.stat.cmu.edu/R/CRAN"}.}
 \item{method}{Tool to be used for downloading files. Currently download
     methods \code{"auto"}, \code{"wget"} and \code{"lynx"} are available. The
     respective program of the same name must be installed on your
     system and be in the PATH.}
 \item{url}{A character string with the URL of a file to be downloaded.}
 \item{destfile}{A character string with the name where the downloaded
     file is saved.}
 \item{pkgs}{A character vector of package names that shall be
     downloaded from CRAN.}
 \item{destdir}{Directory where downloaded packages are stored.}
 \item{available}{List of packages available at CRAN as returned by
     \code{CRAN.packages()}.}
 \item{desc}{A character vector with each element containing one line of
   a package description file.}
 \item{lib, instlib}{A character string giving the library directory where to
     install the packages.}
}
\description{
  These functions can be used to automatically compare the version
  numbers of installed packages with the newest available version on
  CRAN and update outdated packages on the fly.}
}
\details{
    \code{installed.packages()} scans the DESCRIPTION files of each
    package found along \code{lib.loc} and returns a list of package
    names, library paths and version numbers.
    \code{CRAN.packages()} returns a similar list, but corresponding to
    packages currently available in the contrib section of CRAN, the
    comprehensive R archive network. The current list of packages is
    downloaded over the internet (or copied from a local CRAN
    mirror). Both functions use
    \code{parse.description()} for parsing the description files.

    The function \code{download.file()} can be used to download a single
    file as described by \code{url} from the internet and store it in
    \code{destfile}. It makes a system call to the tool given by
    \code{method}, the respective program must be installed on your
    system and be in the search path for executables. Method
    \code{"auto"} (the default) searches for available tools at runtime.

    \code{download.packages()} takes a list of package names and a
    destination directory, downloads the newest versions of the package
    sources and saves the in \code{destdir}. If the list of available
    packages is not given as argument, it is also directly
    obtained from CRAN. If CRAN is local, i.e., the URL starts with
    \code{"file:"}, then the packages are not downloaded but used directly.
    
    The main function of the bundle is \code{update.packages()}. First a
    list of all packages found in \code{lib.loc} is created and compared
    with the pre-compiled packages available on CRAN. Outdated packages
    are reported and for each outdated package the user can specify if
    it should be automatically updated. If so, the pre-compiled packages are
    downloaded from CRAN and installed in the respective library path (or
    \code{instlib} if specified).

    \code{install.packages()} can be used to install new packages, it
    takes a vector of package names and a destination directory,
    downloads the packages from CRAN and installs them.
}
\seealso{
    \code{\link{library}}, \code{\link{.packages}}
}
\keyword{utilities}