pstamp <- if(.R.) function(txt, pwd=FALSE, time.=TRUE)
{
  stamp <- function(string = Sys.time(), print = TRUE, plot = TRUE)
  {
    opar <- par(yaxt='s',xaxt='s',xpd=NA)
    on.exit(par(opar))
    plt <- par('plt')
    usr <- par('usr')

    ## when a logrithmic scale is in use (i.e. par('xlog') is true),
    ## then the x-limits would be 10^par('usr')[1:2].  Similarly for
    ## the y axis
    xcoord <- usr[2] + (usr[2] - usr[1])/(plt[2] - plt[1]) *
      (1-plt[2]) - .6*strwidth('m')
    ycoord <- usr[3] - diff(usr[3:4])/diff(plt[3:4])*(plt[3]) +
      0.6*strheight('m')
      
    if(par('xlog'))
      xcoord <- 10^(xcoord)
    if(par('ylog'))
      ycoord <- 10^(ycoord)

    ## Print the text on the current plot
    text(xcoord, ycoord, string, adj=1)
    invisible(string)
  }

  date.txt <- if(time.) format(Sys.time())
              else format(Sys.time(), '%Y-%m-%d')
  
  if(pwd)
    date.txt <- paste(getwd(), date.txt)

  oldpar <- par(mfrow=c(1,1), cex = 0.5)
  on.exit(par(oldpar))
  if(!missing(txt))
    date.txt <- paste(txt,'   ',date.txt, sep='')
  
  stamp(string=date.txt,print=FALSE,plot=TRUE)
  invisible()

} else function(txt, pwd=FALSE, time.=under.unix)
{

  date.txt <- if(time.) date() else {
    if(.SV4.)
      format(timeDate(date(), in.format='%w %m %d %H:%M:%S %Z %Y',
                      format='%Y-%m-%d'))
    else if(under.unix)
      unix('date +%Y-%m-%d')
    else
      stop('time.=T not supported')
  }
                 
  if(pwd)
    date.txt <- paste(getwd(), date.txt)
  
  oldpar <- par(mfrow = c(1,1), cex = 0.5)
  on.exit(par(oldpar))
  if(!missing(txt))
    date.txt <- paste(txt,'   ',date.txt, sep='')
  
  stamp(string=date.txt,print=FALSE,plot=TRUE)
  par(old)
  invisible()
}