Install https://github.com/asciinema/asciicast2gif on MacOS

install.sh

# the --recursive is important, this has a submodule!
git clone --recursive https://github.com/asciinema/asciicast2gif.git
cd asciicast2gif

# If you forget to use --recursive you can do
git submodule init
git submodule  update

# install npm dependencies
npm install

# install leiningen
brew install leiningen
brew install imagemagick

# build scripts
lein cljsbuild once main && lein cljsbuild once page

# Thats it!
./asciicast2gif

line 7 has a typo; should be submodule. I also needed ImageMagick as well: brew install ImageMagick

Thanks!