Error(s) in re-building vignettes:
  ...
--- re-building ‘concepts.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
--- finished re-building ‘concepts.Rmd’

--- re-building ‘convenience-features.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
--- finished re-building ‘convenience-features.Rmd’

Warning: elapsed-time limit of 1 hours reached for sub-process
--- re-building ‘data-table-syntax.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
grep: can't open "/proc/meminfo"

Execution halted
--- re-building ‘glm.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
grep: can't open "/proc/meminfo"
grep: can't open "/proc/meminfo"
--- finished re-building ‘glm.Rmd’

--- re-building ‘ingesting-data.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
--- finished re-building ‘ingesting-data.Rmd’

--- re-building ‘intro-disk-frame.Rmd’ using rmarkdown
Warning in engine$weave(file, quiet = quiet, encoding = enc) :
  Pandoc (>= 1.12.3) and/or pandoc-citeproc not available. Falling back to R Markdown v1.
grep: can't open "/proc/meminfo"
grep: can't open "/proc/meminfo"
grep: can't open "/proc/meminfo"
Quitting from lines 155-156 (intro-disk-frame.Rmd) 
Error: processing vignette 'intro-disk-frame.Rmd' failed with diagnostics:
Failed to retrieve the value of MultisessionFuture (<none>) from cluster SOCKnode #1 (PID 18034 on localhost 'localhost'). The reason reported was 'error reading from connection'. Post-mortem diagnostic: A process with this PID exists, which suggests that the localhost worker is still alive.
--- failed re-building ‘intro-disk-frame.Rmd’

SUMMARY: processing the following files failed:
  ‘data-table-syntax.Rmd’ ‘intro-disk-frame.Rmd’

Error: Vignette re-building failed.
Execution halted