gum style can do this using the tail command:

brew upgrade | tail -n 10 | gum style --faint --italic

@4Ply thanks but that doesn't stream the results, it just shows the last 10 lines of the brew upgrade

Docker's build command is a great example of what I'm after. Consider:

cat <<-DOCKERFILE | docker build -
FROM debian
RUN apt-get update && apt-get install -y ruby
DOCKERFILE

When Docker build gets to the RUN statement it streams the output as its running

I looked around a bit for this, maybe it would fit as added functionality to gum pager? Sort of like how less does it with F since a few versions now.

I've been thinking of trying to implement this functionality for gum pager over christmas.

1. Are you open to merge requests from general public?
2. is this a good place to start?
   (the idea is to add another function for consuming the stdin as a stream, maybe via a channel)
3. Would you think it's best for this to be a command line argument, a command within the pager interface, both ?

Dang, what @ZOrfeas mentioned would be so appreciated! Been testing different ways to try and stream stdout logs from a running api and was sad gum isn't able to handle it.

For what it's worth, I was able to achieve what I wanted in pure bash: https://github.com/amancevice/spin