What text editor is available in Heroku bash shell?

there's ed if you're a masochist.

If you don't want to mess around with plugins and just want a copy of nano in your one-off dyno, just run

mkdir /app/nano
curl https://github.com/Ehryk/heroku-nano/raw/master/heroku-nano-2.5.1/nano.tar.gz --location --silent | tar xz -C /app/nano
export PATH=$PATH:/app/nano

This will download a copy of nano from this plugin and put it in your PATH.

I recently turned the original gist into a heroku cli plugin.

Just install:

heroku plugins:install https://github.com/naaman/heroku-vim

And use:

heroku vim

The heroku vim command will drop you into a bash shell with vim installed on your $PATH. All you have to do is retrain your fingers to type heroku vim instead of heroku run bash.