[WJW]

For things that take a known amount of time and/or provide updates on progress ("X out of Y items processed"), I'll often include a progress bar with some gem or npm module.

If you don't know how long something is going to take and it emits no intermediate steps, a progress bar won't be useful since it'll go from zero to 100% in one go. One trick I had success with is running the activity like `./myscript; send_push_message "task complete!". The send_push_message in my case pushes to a custom app I wrote some time ago but it could be as simple as sending an email.