

   IInnvvookkee aa SSyysstteemm CCoommmmaanndd

        system(command, intern=FALSE)

   AArrgguummeennttss::

    command: the system command to be invoked, as a string.

     intern: a logical, indicates whether to make the output of
             the command an object.

   DDeessccrriippttiioonn::

        `system' invokes the system command specified by `com-
        mand'.  If `intern' is `TRUE' then popen is used to
        invoke the command and the output collected, line by
        line, into an string vector which is returned as the
        value of `system'.  If `intern' is `FALSE' then the C
        function `system' is used to invoke the command and the
        value returned by `system' is the exit status of this
        function.  This function provides users with the abil-
        ity to invoke system commands on whatever platform they
        are using.

   EExxaammpplleess::

        # list all files in the current directory
        # using the -F flag
        system("ls -F")

        # t1 contains a vector of strings, each one
        # representing a separate line of output from who
        t1 <- system("who", TRUE)

