Why can my command line not recognize Rmarkdown?

Question

I am brand new to R and RMarkdown. I don't have any interest in actually using RStudio, I just want to run my RMarkdown commands on command line to generate PDF's. I have R, RStudio, and Mactex downloaded.I have the following file in my home directory:

DataAnalytics.Rmd

---
 title: "Data Analytics in RMarkdown"
 author: "Jennetta George"
 output:
   pdf_document: default
---

On the command line, I try running in my home directory

Rscript -e "rmarkdown::render('DataAnalytics.Rmd')"

which gives the error

zsh: no matches found: "rmarkdown::render('DataAnalytics.Rmd')"

or I try running

echo "rmarkdown::render('DataAnalytics.Rmd', clean=TRUE)" | R --slave

and get the error

 Error in loadNamespace(name) : there is no package called ‘rmarkdown’
 Calls: :: ... loadNamespace -> withRestarts -> withOneRestart -> doWithOneRestart
 Execution halted

I have googled endlessly for a solution but there is not a lot out there on RMarkdown CLI. Would really appreciate some help troubleshooting this.

Answer 1

Fixed! In RStudio, I ran:

install.packages('knitr', dependencies = TRUE)

and

install.packages('markdown', dependencies = TRUE)

and now it works.