No available formula for “pdfunite” in Homebrew?

To have pdfunite working on OSX, you need to install poppler—which is described as “…a PDF rendering library and command line tools used to manipulate PDF files.”—instead:

brew install poppler

The procedure seems to work a little differently for me. Here's what I've got and hope it would help:

brew install poppler
gem install pdfunite

Then I double checked to see if pdfunite is installed.

gem search ^pdfunite
## *** REMOTE GEMS ***
## pdfunite (0.3.0)

Initially, I was confused whether to use it over Ruby (irb) or just command line. It turns out that you use it in the command line, which is great. For example, to merge my 2 files in the Downloads folder:

cd ~/Downloads/
pdfunite -h #check how to type the syntax
## Usage: pdfunite [options] <PDF-sourcefile-1>..<PDF-sourcefile-n> <PDF-destfile>
pdfunite file1.pdf file2.pdf compiled.pdf #tab-completion is supported