rmarkdown not working due to pandoc

Question

Hi I just updated my version of RStudio and now I cannot create markdown files. I upgraded RStudio to verion: 1.0.136

My version of R is 3.2.5. 

Version of these packages:
knitr: 1.15.1
rmarkdown: 1.4

Note I already installed MikTEX and it was working just fine. I was craeted markdown documents.

Now I Simply create a new r markdown pdf file and click knit and I get this error:

pandoc version 1.12.3 or higher is required and was not found

What do I need to do to get knit to run?

when I run

> pandoc_available(version = NULL, error = FALSE)
[1] FALSE
> 
> pandoc_version()
NULL

Answer 1

If you are on a windows machine this is the simplest way install pandoc.

install.packages("installr")
library(installr) 

install.pandoc()

Answer 2

I had this issue when using a server. I was able to run .Rmd files after installing pandoc through the terminal.

sudo apt-get install pandoc

Then for html output calling the .Rmd with

R -e rmarkdown::render('/path/to/file.Rmd',output_file='/path/to/output.html')