How To Procfile: Run Just a Single Process

February 2019

Reading time: 1 min

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Lets say you’ve got something like this in your Procfile:

web:          PORT=3000 RAILS_ENV=development bundle exec puma -C ./config/puma_development.rb -e development
devlog:       tail -f ./log/development.log
mailcatcher:  ruby -rbundler/setup -e "Bundler.clean_exec('mailcatcher', '--foreground')"%

And you want to run just the stuff in the web line.

Old Josh would have cated the procfile, and copy-pasted most of the top line into the terminal.

New Josh knows better.

$ foreman start web

If I wanted to see just the devlog, I could do:

foreman start devlog

I knew this was possible, I just kept getting the syntax wrong. For example, I tried foreman web, foreman devlog.

Now I know. And so do you.

Additional Reading #

I pieced this together from conversational snippets I heard at work, and Heroku docs on The Procfile