build_one = function(io) {
  # if output is not older than input, skip the compilation
  if (!blogdown:::require_rebuild(io[2], io[1])) return()
  
  message('* knitting ', io[1])
  if (blogdown:::Rscript(shQuote(c('R/build_one.R', io))) != 0) {
    unlink(io[2])
    stop('Failed to compile ', io[1], ' to ', io[2])
  }
}

# Rmd files under the root directory
rmds = list.files('.', '[.]Rmd$', recursive = TRUE, full.names = TRUE)
files = cbind(rmds, blogdown:::with_ext(rmds, '.md'))

for (i in seq_len(nrow(files))) build_one(files[i, ])

#system2('bundle','install')
#system2('bundle','exec jekyll clean')
system2('bundle','exec jekyll build')
#system2('jekyll', 'clean')
#system2('jekyll', 'build')