Modified to run on Linux; original from Will Lowe http://conjugateprior.org/2013/01/no-more-ascii-art/

as_pdf.R

as_pdf <- function(x){
  require(tools)

  fname <- tempfile(pattern = "texview-", tmpdir = tempdir(),
                    fileext = ".tex")

  header <- "\\documentclass{article}
             \\usepackage[margin=10pt,font=small,labelformat=empty,
                          labelsep=none]{caption}
             \\usepackage{dcolumn}
             \\thispagestyle{empty}
             \\begin{document}"
  footer <- "\\end{document}"

  cat(header, file=fname, sep='\n')
  cat(x, file=fname, append=TRUE)
  cat(footer, file=fname, append=TRUE, sep='\n')

  newfile <- paste0(file_path_sans_ext(fname), ".pdf")
  cropfile <- paste0(file_path_sans_ext(fname), "-crop.pdf")

  origdir <- getwd()
  tryCatch({
      setwd(tempdir()) ## next to the tex file
      texi2pdf(fname, clean=TRUE)
      system2("pdfcrop", args=c("--margins", "10", newfile, cropfile),
              stdout=FALSE)
    }, finally=setwd(origdir))

  system2("evince", args=c(cropfile))
  ## shell.exec(file_path_as_absolute(cropfile)) ## for Windows, probably
}